Journal of Prosthodontic Research
Online ISSN : 1883-9207
Print ISSN : 1883-1958
ISSN-L : 1883-1958
Advance online publication
Showing 1-50 articles out of 71 articles from Advance online publication
  • Moritz Waldecker, Wolfgang Bömicke, Rouven Behnisch, Peter Rammelsberg ...
    Type: Original article
    Article ID: JPR_D_21_00100
    Published: 2021
    [Advance publication] Released: December 07, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: This in-vitro study aimed to compare the accuracy of complete arch scans (CAS) of a fully dentate (FD) and a partially edentulous (PE) maxillary model. Three intraoral scanning systems were used: Omnicam AC (OC), TRIOS 4 (TR), and Primescan (PS).

    Methods: Each intraoral scanner was used to take 30 scans each of two clinical scenarios (FD and PE) simulated by a reference model. The PE model simulated a maxilla with six prepared teeth to accommodate a jaw-spanning fixed partial denture (FPD). The missing teeth were then added to create an FD model. Five ceramic precision balls (ball centers P1–P5) mounted on metal pins were welded to the metal base on the buccal side of the dental arch. These were later used to determine dimensional (given by each 2 ball centers) and angular changes (given by each 3 or 4 ball centers) between the reference model (digitized with high precision before the tests) and the intraoral scans. Data were statistically analyzed using a type II ANOVA.

    Results: The maximum mean absolute distance deviations were as follows. OC: 147 µm (FD) and 139 µm (PE). TR: 133 µm (FD) and 136 µm (PE). PS: 87 µm (FD) and 80 µm (PE). The scanning system used had a significant effect on distance deviations (p < 0.027) and CAS scanning time (p < 0.001). Dental status had no clear effect on distance deviations but did significantly affect angular changes (p < 0.001) and scanning time (p < 0.001).

    Conclusion: The manufacture of jaw-spanning FPDs based on a CAS cannot yet be recommended.

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  • Raquel Alonso-Pérez, José F. Bartolomé, Guillermo Pradíes
    Type: Original article
    Article ID: JPR_D_20_00066
    Published: 2021
    [Advance publication] Released: December 06, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: To assess the internal accuracy and mechanical behaviour under cyclic loading after artificial aging of implantsupported crowns restored with original stock abutments and two compatible non-original stock abutments.

    Methods: Forty-eight original internal hexagon connection implants were connected to different stock abutments. The samples were divided into three groups depending on the manufacturer of the abutment components (one original, two non-originals).

    Firstly, samples were cross-sectioned and observed by using Scanning Electron Microscope (SEM) to evaluate the internal accuracy in three different implant-abutment interface locations (platform, internal and screw). Further, cyclic fatigue loading was carried out according to the ISO Norm 14801 using dynamic testing machine under sinusoidal loads for 2,000,000 cycles at test frequencies of 2 Hz in air after thermocycling with 10,000 cycles at 5 °C and 55 °C in artificial saliva for aging simulation.

    Results: Original abutment components presented the highest percentage of surface with tight contact with the implant in the three implant-abutment interfaces studied. Additionally, original configuration showed highest fatigue limit value and fatigue strength exponent (280 N and -0.054) than non-original 1 (225 N and -0.109) and non-original 2 (200 N and -0.101).

    Conclusion: Original abutment components provide better fit and mechanical results under cyclic loading than nonoriginal configurations. The results obtained in this study seem to suggest that the use of the original stock abutments to implants leads to a more homogeneous load distribution between the components that can influence the long-term success of the restorations.

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  • Maher Eldafrawy, Sandrine Bekaert, Jean-François Nguyen, Michaël Sadou ...
    Type: Original article
    Article ID: JPR_D_21_00044
    Published: 2021
    [Advance publication] Released: December 02, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: To compare the interfacial fracture toughness (IFT) of two MDP-based composite cements and a resin-modified glass-ionomer cement (RMGIC) with third-generation zirconia CAD-CAM restorations using two different airborne-particle abrasion (AB) pressures.

    Methods: Blocks were cut into prisms (n=60), split and sintered to the desired equilateral half prisms. Half-prisms were divided into two groups for AB at 0.5 or 2.5 bar with 50 µm Al2O3 particles. Each group was then further divided into 3 subgroups, and half-prisms were bonded to their counterparts with Panavia V5 (V5), Panavia Self Adhesive Cement Plus (SA), or RMGIC Fuji Plus (n=10/group). The IFT was determined using the Notchless Triangular Prism test in a water bath at 36°C after thermocycling (10,000 cycles). Surface roughness and SEM analyses were performed for representative zirconia samples after AB, and composite cements were tested for flexural strength and wettability.

    Results: SA (2.5 bar) showed a significantly higher IFT. The 3 other groups with SA and V5 showed no significant difference in their IFT values regardless of the AB pressure (1-way ANOVA). Weibull analysis of SA was higher than V5. All RMGIC samples debonded while thermocycling, and were, therefore, not included in the statistical analysis. Surface roughness increased with increasing AB pressure, and both cements showed similar flexural strength values and good wettability.

    Conclusion: Contrary to RMGIC, composite cements show high performance with zirconia after AB. Increasing AB pressure enhances the micromechanical retention of composite cement. Future perspectives should include study of the effect of AB pressure on zirconia surface properties.

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  • Melissa David-Pérez, Juan P. Ramírez-Suárez, Federico Latorre-Correa, ...
    Type: Original article
    Article ID: JPR_D_20_00090
    Published: 2021
    [Advance publication] Released: December 01, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: This systematic review synthesized and analyzed the scientific evidence on the degree of conversion (DC) obtained by Fourier-transform infrared spectroscopy (FTIR) of light-cured and dual-cured resinous cements, photopolymerized under different thicknesses of vitreous ceramics.

    Study selection: The study protocol of this systematic review was registered at the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42017069319). A comprehensive search (PubMed/MEDLINE, Scopus, EMBASE, and LILACS) was performed for papers including an in vitro design and indexed from January 2007 to December 2020 according to the study purposes. A quality appraisal (specific instrument) and descriptive analysis of the articles that met the inclusion criteria were conducted.

    Results: Nine included studies were analyzed. Two of them used feldspathic ceramics, six used lithium disilicate, and one used both (comparing different types and opacities of ceramics). Three studies found a higher DC in dual cements, while one did not find any significant differences, and five studies found a higher DC in light-cured resin cements. Light-cured cements showed a better DC in relation to dual-cured cements in vitreous ceramic restorations with thicknesses up to 2 mm.

    Conclusion: According to the findings, the use of good photoactivation is the most relevant variable to achieve an adequate DC in light-cured and dual-cured resin cements. The use of vitreous ceramic restorations with a thickness of less than 2 mm (light-curing cements) shows a better DC. Standardized in vitro studies are required to generate accurate scientific evidence.

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  • Li-xian Zhang, Deng-wei Hong, Ming Zheng, Hao Yu
    Type: Original article
    Article ID: JPR_D_20_00112
    Published: 2021
    [Advance publication] Released: December 01, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: This study systematically reviewed the literature to compare the bond strength of resin composites with that of zirconia-reinforced lithium silicate (ZLS) and lithium disilicate (LD).

    Study selection: This review was structured based on the Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA 2020) statement. This study was registered at the International Prospective Register of Systematic Reviews (CRD42021256900). Studies were searched via PubMed, Web of Science, and Google Scholar databases without language or publication year limits. In vitro studies that evaluated the bond strength of the resin composites to ZLS and LD were included. The risk of bias in all the included articles was evaluated. Statistical analyses were performed using the Review Manager software (version 5.3, Cochrane Collaboration, Oxford, UK).

    Results: Of the 90 potentially related articles, the full texts of 16 articles were evaluated after screening. Finally, sevenstudies were included in the qualitative synthesis and meta-analysis. All the studies presented a medium risk of bias. The results showed no significant difference in bond strength between the ZLS and LD groups (P = 0.94, mean difference=0.08, and 95% confidence interval=-1.93 to 2.10). However, a significant difference was found in the subgroup analysis considering different types of aging treatments (P = 0.0008) and different types of bond strength tests (P < 0.00001).

    Conclusion: The bond strength of resin composites was found to be similar to that of ZLS and LD, but different aging treatments and bond strength tests exhibited varying effects on the bond strength.

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  • Adolfo Di Fiore, Roberto Meneghello, Paola Brun, Stefano Rosso, Albert ...
    Type: Original article
    Article ID: JPR_D_21_00116
    Published: 2021
    [Advance publication] Released: December 01, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: To compare the flexural properties and the adhesion of Lactobacillus salivarius (LS), Streptococcus mutans (SM), and Candida albicans (CA) on heat-polymerized (CV), CAD-CAM milled (CAD), or 3D-printed (3D) Poly (methylmethacrylate) (PMMA).

    Methods: Ultimate Flexural Strength (UFS), Flexural Strain (FS) (%) at Flexural Strength, and Flexural Modulus (FM) of specimens (65.0×10.0×3.3 mm) from each PMMA group (n=6) were calculated by using the 3-point bending test. The surface roughness profiles (R) were measured before and after polishing with a contact profilometer. LS, SM, and CA adhesion on PMMA specimens (n=18) (10 mm in diameter, 3 mm in height) was assessed after 90 minutes and 16 hours by using scanning electron microscopy. The Kruskal-Wallis test with post hoc analysis was performed to compare the groups (alpha=0.05).

    Results: Mean UFS values were 80.79±7.64 MPa for CV, 110.23±5.03 MPa for CAD, and 87.34±6.39 MPa for 3D. Mean FS values were 4.37±1.04% for CV, 4.71±0.62% for CAD, and 6.19±0.13 % for 3D. Mean FM values were 2542±301 MPa for CV, 3435±346 MPa for CAD, and 2371±197 MPa for 3D. CAD had the lowest average R value (0.29±0.16 µm) before polishing, and bacterial adhesion after 90 minutes of incubation. R value and microbial adhesion were not different amongst groups after polishing and 16 hours of incubation, respectively.

    Conclusion: The CAD group displayed the best flexural properties, except for FS, the lowest roughness before polishing and bacterial adhesion after 90 minutes of incubation. All tested PMMAs had similar surface roughness after polishing, and microbial adhesion after 16 hours of incubation.

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  • Eleni Siarampi, Katia Sarafidou, Lambrini Papadopoulou, Nikolaos Kanti ...
    Type: Original article
    Article ID: JPR_D_21_00067
    Published: 2021
    [Advance publication] Released: November 30, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: The investigation of zirconia core surface pretreatments on the flexural strength of bilayered zirconia ceramics before and after artificial accelerating aging.

    Methods: Ninety bar-shaped specimens were manufactured from Yttria Stabilized Tetragonal Zirconia Polycrystal (Y-TZP) and divided in three groups depending on zirconia surface pretreatment before veneering: layering with liner, pretreatment with silane-containing gas flame (SGF) with the Silano-Pen device and alumina air-abrasion. Half of the veneered specimens in each group (n=15) underwent artificial accelerating aging. A 4-point bending test was performed to determine flexural strength. Three specimens from each group were further analyzed using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) before veneering and after fracture (aged and non-aged subgroups).

    Results: Alumina air-abrasion was correlated to increased phase transformation from tetragonal to monoclinic zirconia phase. Qualitative analysis revealed that with the majority of the specimens pretreated with the silane-containing gas flame, areas of the veneering material remained firmly attached to the zirconia core after flexural strength testing. There was no statistically significant difference on the flexural strength among the groups before or after aging. Artificial accelerating aging resulted in statistically significant higher flexural strength of the specimens after aging.

    Conclusion: SGF pretreatment can be an acceptable and feasible alternative method before the veneering of Y-TZP zirconia as it presented slightly higher bond strength compared with alumina air-abrasion which was associated with higher tetragonal to monoclinic (tm) phase transformation. Accelerating aging leads to an increase of the mechanical properties under in vitro conditions.

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  • Hikaru Sugimoto, Yuki Tanaka, Naoki Kodama, Shogo Minagi
    Type: Original article
    Article ID: JPR_D_21_00069
    Published: 2021
    [Advance publication] Released: November 30, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: To examine how particle loss affects the evaluation of masticatory ability using the image analysis method.

    Methods: The subjects were divided into two groups:Y-group (healthy young adults: 10 male, 10 female; mean age 27.6 ± 1.9 years), and D-group (denture wearing older adults: 13 male, 9 female; mean age, 75.1 ± 5.3 years). Raw carrots, peanuts, and a combined test food from 5 daily food materials (mixed foods) were selected as test foods. Images of the boluses were captured and processed after the subjects freely masticated the test foods until the point of swallowing or completed half strokes of total chewing cycles. The median particle size (X50) was calculated from the data for each particle. We compared X50 calculated from all particles obtained from the masticatory bolus (as X50N) with the X50 of only selectively larger particles (as X50R).

    Results: Significant correlations were observed between X50N and X50R (p < 0.01) determined in almost all masticatory conditions. In particular, for particle sizes of 2 mm or more, the correlation coefficient between X50N and X50R was notably strong (r > 0.75).

    Conclusion: The method of analyzing only larger particles makes it possible to evaluate masticatory ability without losing the characteristics of the original particle size distribution of the entire bolus. This finding can be applied for the evaluation of masticatory ability, especially among older adults who have difficulty retrieving the total amount of test food due to decreased activities of daily living.

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  • Akinori Tasaka, Takahiro Shimizu, Shuichiro Yamashita
    Type: Original article
    Article ID: JPR_D_21_00127
    Published: 2021
    [Advance publication] Released: November 30, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Patient: This clinical report describes treatment with a double-crown-retained removable dental prosthesis fabricated using an intraoral scanner (IOS) and computer-aided design/manufacturing technology (CAD/CAM). A 68-year-old female patient presented with complaints of missing maxillary right first and left second premolars. CAD/CAM technology was applied to plan treatment with a double-crown-retained removable dental prosthesis. The patient consented to this treatment option but did not want orthodontic treatment for the anterior crossbite of the right side. After the definitive preparation of the abutment teeth, the shape of the provisional restoration was adjusted to match the definitive prosthesis. An IOS was used to obtain digital scans of the provisional restoration, occlusion, antagonist arch, and prepared surface of the abutment teeth. First, the primary crowns were milled from cobalt-chromium alloy. Next, using an intraoral scanner, a pickup impression of the primary crowns was performed, and the secondary crowns were designed, milled, and veneered. After delivery, the patient expressed satisfaction with the functionality, esthetics, and fit of the double-crown-retained removable dental prosthesis.

    Discussion: The surface of the primary crowns was coated with scan spray when the pick-up impression was made using the IOS. Practice is needed to achieve a thin and homogeneous coating with scan spray to improve reproducibility.

    Conclusion: Double-crown-retained removable dental prostheses can be successfully fabricated using an IOS and CAD/CAM technology, resulting in patient satisfaction.

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  • Leandro Passos, Sergio Meiga, Vinicius Brigagão, Marcus Neumann, Alexa ...
    Type: Original article
    Article ID: JPR_D_20_00089
    Published: 2021
    [Advance publication] Released: November 18, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: This technical procedure describes the accuracy of “cut-out–rescan” and “data exchange by over scanning” on cast areas using computer-aided design and computer-aided manufacturing software and two intraoral scanners (IOSs).

    Methods: A customized cast was used as a reference standard and scanned using an ATOS Triple Scan digitizer. Two IOS setups were used in three scanning groups, namely, the control, cut-out–rescan, and data exchange by over scanning groups. Sixty digital files (n = 10 per group) were obtained and converted into the standard tessellation language format. A metrology program was used to evaluate the difference in accuracy between the control group and the other groups using Welch’s unequal variances t-test.

    Conclusion: For trueness and precision of complete arch scans, the present technique provides statistical evidence that using data exchange by over scanning and a Primescan IOS results in higher accuracy scans compared to using cut-outrescan and a Primescan IOS. The cut-out–rescan procedure provides scans with higher accuracy when using an Omnicam IOS. This technique is simple and saves time in workflows using a Primescan IOS

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  • Yoko Kato, Takeshi Kikutani, Keiichiro Sagawa, Fumiyo Tamura
    Type: Original article
    Article ID: JPR_D_20_00285
    Published: 2021
    [Advance publication] Released: November 18, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This study examined the association between masticatory movement and oral and physical function in healthy older women using clinical assessments considering central motor control.
    Methods: A total of 107 independent older women (mean age, 74.37 ± 4.46 years; age range, 66–84 years) living in the community participated in this cross-sectional study. The subjects selected were those aged 65 years or older with at least 28 teeth and without oral dysfunction, temporomandibular joint (TMJ) disease, cerebrovascular disease, or neuromuscular disease. The following items of oral and physical function were measured: masticatory path pattern, masticatory perfor-mance, oral diadochokinesis (ODK), tongue pressure, single-leg stance with eyes open (SLS), stepping test, and grip strength. Logistic regression analysis adjusting for age was performed to investigate the association between masticatory movement and other items.
    Results: In total, 30.8% of subjects were classified into the abnormal group regarding masticatory path pattern, having a significantly lower value than that of the normal group in masticatory performance (unadjusted p = 0.021). After adjusting for age, the masticatory path pattern was significantly associated with masticatory performance ( p = 0.032); ODK /pa/ ( p < 0.001), /ta/ ( p = 0.022), and /ka/ ( p = 0.016); and stepping test ( p = 0.018). Tongue pressure, SLS, and grip strength were not significantly associated with masticatory path pattern.
    Conclusion: Masticatory movement in older women was associated with masticatory performance, tongue and lip motor skills, and physical agility, which might be influenced by central motor control.
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  • Keigo Nagashima, Takeshi Kikutani, Noriaki Takahashi, Yoko Kato, Keiic ...
    Type: Original article
    Article ID: JPR_D_20_00290
    Published: 2021
    [Advance publication] Released: November 18, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This study aimed to develop a simple screening test for mastication, “the Sakiika (squid jerky) transport test (STT), which evaluates the vertical jaw movement coordinated with the lateral tongue movement during stage I transport, and investigate the possibility of its clinical application.
    Methods: The study included 73 people with dysphagia (mean age, 78.5 ± 7.8 years; median age, 79.0 years; interquartile range, 75.0–84.0). The STT evaluated the ability of a participant to transport a piece of squid jerky placed on the midline of the tongue to the molar region. The STT score was defined as the number of vertical jaw movements occurring as the tongue transported food to the molars. A cutoff value was set by comparing the STT scores with masticatory function evaluated via a videofluoroscopic swallowing study and with food texture evaluated using the Food Intake LEVEL Scale (FILS).
    Results: The STT scores counted by the two examiners had a κ coefficient of 0.79, indicating good reliability. The STT score was significantly associated with both the presence of masticatory movement ( p = 0.019) and food texture classified by FILS ( p = 0.032) at cutoff value of “3” (3 vertical movements). The STT showed 62% sensitivity and 75% specificity for masticatory movements.
    Conclusion: The STT could be a useful screening test to assess the presence or absence of food transportation to the molars for mastication in older patients with dysphagia. In addition, the STT could be useful in identifying the need to modify food texture to meet functions.
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  • Hirofumi Uchida, Junichiro Wada, Chie Watanabe, Tomiharu Nagayama, Koj ...
    Article ID: JPR_D_21_00230
    Published: 2021
    [Advance publication] Released: November 16, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: The purpose of this study was to investigate the inhibitory effect of night denture (ND) placement on abutment tooth mobility in removable partial denture (RPD) wearers with sleep bruxism (SB).

    Methods: The participants were selected from RPD wearers diagnosed with SB using BiteStrip® and randomly allocated to one of the following groups: with ND placement or without ND placement (intervention or control group, respectively). The mobility of the RPD abutment tooth was measured using Periotest® at baseline (T0) and at 1 (T1), 3 (T3), and 6 months (T6). BiteStrip® scores were recorded at T0 and T6. Intragroup comparisons of the Periotest® value (PTV) were performed using analysis of covariance. Intergroup comparisons of PTV and BiteStrip® scores were performed using the linear mixed model and Wilcoxon signed-rank test, respectively. Intragroup comparisons of BiteStrip® scores were performed using the Mann–Whitney U test.

    Results: At T6, the PTV in the intervention group was significantly lower than that in the control group (p=0.004). PTV was significantly lower at T6 than that at T0 in the intervention group (p=0.030), while PTV was significantly higher at T6 than that at T0 in the control group (p=0.007). There was no significant difference in the BiteStrip® score between the two groups. The BiteStrip® score at T6 was significantly lower than that at T0 only in the intervention group (p=0.011).

    Conclusion: ND placement might inhibit the increase in mobility of RPD abutment teeth and be effective in protecting them in RPD wearers with SB.

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  • Bor-Shiunn Lee, Kuo-Chung Cheng, Bo-Han Zeng, Po-Chih Wang, Tsung-Chie ...
    Article ID: JPR_D_21_00088
    Published: 2021
    [Advance publication] Released: November 09, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: To develop a novel resin for provisional prostheses using hyperbranched polyurethane acrylate (HBPUA) and triethylene glycol dimethacrylate (TEGDMA) with promising mechanical properties and low volumetric shrinkage.

    Methods: Four groups including TIH3-0 (100 wt% TEGDMA), TIH3-30 (30 wt% HBPUA + 70 wt% TEGDMA), TIH3-60 (60 wt% HBPUA + 40 wt% TEGDMA), and TB-60 (60 wt% bisphenol A-glycidyl dimethacrylate + 40 wt% TEGDMA) were prepared and commercial Luxatemp (DMG) was used for comparison. Fourier transform infrared spectroscopy and gel permeation chromatography were used for material characterization. Mechanical properties including microhardness, flexural strength, flexural modulus, and load energy were measured before and after water immersion. Physical properties measurement included weight changes, solubility, water absorption, surface hydrophobicity, and volumetric shrinkage. Finally, biocompatibility was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay.

    Results: The number- and weight-average molecular weights of the HBPUA were approximately 870 and 1480, respectively. The addition of HBPUA to TEGDMA increased the mechanical strength considerably. Although the weight changes and water absorption of TIH3-60 were higher than those of Luxatemp, the microhardness, flexural strength, flexural modulus, load energy, solubility, shrinkage, and biocompatibility of TIH3-60 were either comparable or superior to those of Luxatemp.

    Conclusion: Based on the findings of the present study, TIH3-60 has potential for development as a new provisional material.

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  • Yoshiteru Furuya, Suguru Kimoto, Nobuhiko Furuse, So Furokawa, Kentaro ...
    Article ID: JPR_D_21_00159
    Published: 2021
    [Advance publication] Released: October 30, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: This randomized controlled trial (RCT) aimed to elucidate the effectiveness of silicone-based resilient denture liners on perceived chewing ability.

    Methods: The RCT included completely edentulous patients on both the maxilla and mandible, who were willing to fabricate a new set of complete dentures. A random permuted block method (block size: 4) was used to assign groups to receive maxilla conventional complete denture and mandibular with either a conventional complete denture (CD) or complete demure relined with silicone-based resilient denture liner (RD). The patient-reported chewing ability of six foods, soybean curd, fish sausage, soybean sprout, cubic rice cracker, hard rice cracker, and dry squid, on a 100-mm visual analog scale was measured and reported at the final adjustment and three months after the final adjustment. Mann-Whitney U test was used to analyze the differences between the CD and RD (p < 0.05).

    Results: Edentulous patients wearing mandibular complete denture with RD had a higher patient-reported chewing ability than those wearing a CD, but the fish sausage did not in the RD three months after the final adjustment. It also took three months for the patient-reported masticatory ability to improve for cubic rice crackers, hard rice crackers, and dry squid and to show a difference between the RD and CD groups.

    Conclusion: Although limited to some food types, mandibular complete dentures relined with silicone-based liners improved patient-reported chewing ability.

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  • Kazumichi Yonenaga, Shunsuke Itai, Kazuto Hoshi
    Article ID: JPR_D_21_00064
    Published: 2021
    [Advance publication] Released: October 26, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: It is over a year since the first case of coronavirus disease (COVID-19) was confirmed in China. This paper reviews and summarizes the characteristics of COVID-19, as understood of December 2020, from a dental perspective.

    Study Selection: The PubMed and Scopus online databases were searched using a combination of free words and Medical Subject Headings terms: “dentist” OR “oral care” AND “COVID-19” OR “SARS-CoV-2.”

    Results: Older people and those with underlying medical conditions have an increased risk of serious illness due to COVID-19. The virus enters the body by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. It is common for people with COVID-19 to have mild or no symptoms. Moreover, the disease is not contagious in most infected people; it is only highly contagious in some infected people, thereby forming clusters. Due to the large number of virus particles that are shed prior to the onset of symptoms of the disease, retrospective surveys are important. Appropriate personal protective equipment against corona vortices is also important in clinical practice. Although polymerase chain reaction tests are useful for confirming infection in suspected individuals, their reliability is questionable. In addition, concerns regarding long-term sequelae have been reported.

    Conclusions: There are few high-quality reports on the implications of COVID-19 in dental practice. However, reports suggest that insufficient oral hygiene may be a risk factor for infection. Reports that ACE2 receptors are abundant in the oral cavity also suggest the importance of oral care.

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  • Harini Padmanabhan, Siddharth S. Vijayakumar, Parthasarathy N, V. Anan ...
    Article ID: JPR_D_21_00099
    Published: 2021
    [Advance publication] Released: October 15, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: This study aims to evaluate the effect of rehabilitation with complete dentures versus implant-retained overdenture on activity in various parts of the brain cognition in a geriatric edentulous population via Functional MRI (fMRI) studies and the Mini-Mental State Examination (MMSE).

    Methods: Ten completely edentulous patients were rehabilitated with both complete dentures and two-implant retained overdentures for three months each. fMRI studies were performed for each modality during chewing and recall tasks at three time periods: T0: Completely Edentulous(CE) T1: after three months of wearing Conventional Complete Dentures(CD) and T2: after three months of wearing Implant-retained Overdentures (IOD). The Z scores obtained from the fMRI at these phases of examination were tabulated and correlated with MMSE scores obtained at the corresponding time periods.

    Results: Z scores obtained during the memory recall tasks at T2 were the greatest (Prefrontal Cortex (p=0.059) and Hippocampus (p=0.036). The MMSE scores obtained were significantly higher for the IODs when compared to the CDs and Baseline values (p < 0.05)

    Conclusion: IODs may potentially result in superior sensory feedback in edentulous patients and lead to improved cognitive performance when compared to conventional complete dentures.

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  • Mai Murase, Hiroko Tani, Yuka I Sumita, Shuichi Ino, Hisashi Taniguchi
    Article ID: JPR_D_20_00250
    Published: 2021
    [Advance publication] Released: October 14, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Patient: A 69-year-old Japanese male with squamous cell carcinoma of the right maxilla (T4M0N0) was referred to our department for a preoperative examination. An immediate surgical obturator was fabricated before surgery. He underwent surgical treatment, which included right subtotal maxillectomy and reconstruction with a split skin graft. One week postoperatively, the immediate surgical obturator was modified to expand the nasal cavity for obturator prosthesis. Oral intake was started 12 days postoperatively with an immediate surgical obturator in situ. The definitive obturator was fabricated after the wound surface had healed 8 months postoperatively. Assessment of the nutritional status included body mass index, serum albumin level, resting energy expenditure (REE) measured using indirect calorimetry, and predicted REE using the Harris-Benedict equation. These assessments were performed several times, from the time of admission until the definitive obturator was applied.

    Discussion: Malnutrition occurs frequently in patients with head and neck cancer because this region is vital for swallowing and mastication. Maxillectomy patients require a maxillofacial prosthesis to improve their nutritional status from the preoperative period to recovery. This case report describes maxillofacial prosthetic treatment from the perspective of nutrition. The patient wore the immediate surgical obturator postoperatively, which was followed by marked weight loss after restoration, and then weight gain returned to the normal range when wearing the definitive obturator.

    Conclusion: Maxillofacial prosthetic treatments should make efforts to maintain nutritional status and achieve optimal function and quality of life in patients with head and neck cancers.

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  • Marietta Taylor, Mohd Masood, George Mnatzaganian
    Article ID: JPR_D_20_00323
    Published: 2021
    [Advance publication] Released: October 14, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: There is little evidence as to what is the appropriate replacement interval for complete dentures. The aim of this study was to determine the longevity of complete dentures in a population of publicly insured adults across a 20 year observation period.

    Methods: The records of 187,227 Australian adults who accessed complete denture treatment through public clinics between 2000-2019 were assessed. Time to denture replacement was modelled using a Weibull regression and a competing risk regression to adjust for the competing risk of mortality.

    Results: Over a 20-year period, 27.7% of dentures were replaced, with a mean longevity of 6.06 (SD: 3.93) years. Pairs of complete dentures had greater mean longevity than single dentures (p<0.001). Approximately 4.6% of dentures provided were replaced within 2 years; 18.4% were replaced between 2 and 10 years and 4.6% of replacements occurred after 10 years.

    Over 70% of adults who received a complete denture did not replace it during the observation period. Dentures provided by denturists had higher levels of replacement than those made by dentists. Participants over 80 years of age had lower rates of denture replacement. Low socio-economic status and living outside a major city were associated with reduced rates of replacement for dentures under 10 years of age.

    Conclusion: Complete dentures were commonly replaced after 6 years of service. Pairs of dentures lasted longer than single dentures.

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  • Manman Zhang, Ning Gan, Haixin Qian, Ting Jiao
    Article ID: JPR_D_21_00017
    Published: 2021
    [Advance publication] Released: October 06, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: Evaluating the fitness accuracy and retentive force of cobalt-chrome (Co-Cr) alloy clasps fabricated using the selective laser melting (SLM) technique.

    Methods: Premolar and molar abutment models with a 0.5-mm undercut depth, 1.5-mm-thick occlusal rest seats, and guiding planes were designed and fabricated using a milling machine. On these models, Akers clasps with 0.25- and 0.5-mm undercut depths were designed and fabricated with SLM and a traditional lost wax casting method. Based on the manufacturing methods, abutment types, and undercut depths, the clasps were divided into eight groups (10 per group). The fitness accuracy of the clasps was evaluated by measuring the gap distance between the clasps and abutments using a silicone film method. The initial retentive force and changes in retention up to 7,200 insertion/removal cycles of the clasps were also measured. The data were analyzed using multiple linear regression, paired t-tests, and one-way ANOVA (α=0.05).

    Results: For both the SLM and cast clasps, the fitness accuracy of the rest was greater than that of the clasp tip and shoulder. No significant difference was found in the fitness accuracy between the SLM and cast clasps, regardless of the abutment type and undercut depth before or after insertion/removal cycles (p>0.05). There was also no significant difference in the initial retentive force between the SLM and cast clasps (p>0.05). After 7,200 insertion/removal cycles, the SLM clasp exhibited a greater residual retentive force (p<0.05).

    Conclusion: The SLM technique for manufacturing the clasps of removable partial dentures has promising clinical applications.

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  • Celina Inês Miranda Brito Leitão, Gustavo Vicentis de Oliveira Fernand ...
    Article ID: JPR_D_21_00081
    Published: 2021
    [Advance publication] Released: October 06, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: The purpose of this systematic review was to evaluate the survival rate, biological complications, technical complications, and clinical behavior of single crowns supported by teeth made up in monolithic zirconia with CAD/CAM technology.

    Study selection: An extensive electronic search was conducted through Medline/PubMed, Embase, and Cochrane Library databases. Additional manual search was performed on the references of included articles to identify relevant publications. Two reviewers independently performed the selection and electronic and manual search.

    Results: From nine articles included, there was a total of 594 participants and 1657 single-tooth restorations with a mean exposure time of 1.07 years, and follow-up period between 0.3 and 2.1 years. All studies showed a moderate level of quality, with a consequent moderate possibility of associated bias, using the Newcastle-Ottawa Scale (NOS), with survival rate (SR) ranging between 91% to 100%. Bleeding on probing (BOP) were reported with an average value of 29.12%. Marginal integrity showed high success rate values for the observation periods, except for one that included patients with bruxism which obtained a SR of 31.60%. Failures and/or fractures, mostly total and requiring replacement, were observed in three studies. Linear regression showed that there was no statistical correlation between survival rate and type of cementation and the average years of follow-up (p=0.730 e p=0.454). There was high heterogeneity between studies (I2 = 93.74% and Q = 79.672).

    Conclusions: Within the limitation of this study, monolithic zirconia might be considered as a possible option for restoring single crowns, especially in the posterior zone.

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  • Jing Wang, Peng Wu, Hai-lin Liu, Ling Zhang, Li-peng Liu, Chu-fan Ma, ...
    Article ID: JPR_D_20_00142
    Published: 2021
    [Advance publication] Released: September 30, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: To evaluate the performance of polyetheretherketone (PEEK) versus titanium computer-aided designed and manufactured (CAD-CAM) framework for implant-supported fixed complete dentures (ISFCDs) with a follow-up for a duration of up to 5 years.

    Methods: Consecutively edentulous patients who underwent ISFCDs with a PEEK framework or titanium framework at one dental specialist center were included in this retrospective study. Implant/prosthesis survival rates, mechanical/biological complications, and bone and soft tissue parameters were analyzed. Overall survival was analyzed using Kaplan-Meier survival curves and the log-rank test.

    Results: Sixty ISFCDs (29 PEEK, 31 titanium) performed on 43 edentulous patients (331 implants) were included. An implant survival rate of 100% was obtained. There was no significant difference in the cumulative prosthesis survival rate between the PEEK (93.1%) and titanium groups (93.5%). The most common mechanical complications were fracture of the artificial veneer in both the PEEK (13.8%) and titanium (16.7%) groups. Bruxers had a higher prevalence of mechanical complications than non-bruxers (p<0.05). The biological complications included bleeding upon probing (13.8% for the PEEK group; 16.1% for the titanium group), soft tissue inflammation (3.4% for the PEEK group; 3.2% for the titanium group), and temporomandibular disorders (6.5% for the titanium group). The vertical bone loss was significantly lower in the PEEK group (0.70 mm) than in the titanium group (0.96 mm). Smokers had a significantly higher prevalence of biological complications than non-smokers.

    Conclusions: Within the limitations of this study, ISFCDs with PEEK frameworks can provide good prognosis for edentulous patients, still requiring longer-term validation.

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  • Yurina Takaoka, Yosuke Akiba, Masako Nagasawa, Akiko Ito, Yukiko Masui ...
    Article ID: JPR_D_20_00307
    Published: 2021
    [Advance publication] Released: September 30, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: This study aimed to investigate the relationship between dental metal allergy, periodontitis, and palmoplantar pustulosis among patients from a dental metal allergy clinic over a period of 8 years.

    Methods: This study included 436 patients who visited our dental metal allergy clinic between April 1, 2009 and March 31, 2016. Diagnoses of skin diseases, periodontal records, dental metal series patch test results, and electron probe microanalysis (EPMA) data were obtained from medical records. Relative risk (RR) values were estimated from these data.

    Results: Of the 359 patients who underwent the patch test, 241 showed a positive reaction. Of the 187 patients who underwent EPMA, 113 had allergenic metals in their dental prostheses. These patients were suspected to have a dental metal allergy. Furthermore, 150 of the 436 patients were diagnosed with palmoplantar pustulosis (PPP). The RR of metal allergy between patients with PPP and healthy subjects was 3.88. The RR of periodontal disease between patients with PPP and PPP-negative patients in the national average was 2.54.

    Conclusions: In this study, both dental metal allergy and periodontitis showed a high RR for PPP.

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  • Ye Bi, Taghrid Aldhohrah, Mubarak Ahmed Mashrah, Yucheng Su, Zhe Yang, ...
    Article ID: JPR_D_21_00073
    Published: 2021
    [Advance publication] Released: September 30, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: To evaluate the effect of overdenture (OD) attachment type and the number of implants supporting mandibular ODs on peri-implant health.

    Study selection: From inception to October 2020, electronic databases (Medline/PubMed, Embase, Cochrane Library, and Scopus) were systematically searched. The outcomes of interest were marginal bone loss (MBL), pocket probing depth (PPD), plaque index, bleeding index, and implant survival rate. Bayesian network meta-analysis was performed using the GeMTC package supported by R. The weighted mean difference and 95% credible interval were estimated.

    Results: Twenty-eight studies with a total of 1166 participants who received 2666 dental implants were included. Except for 4 bar and 4 telescopic, which showed a statistically lower MBL than the 2 locator, all other interventions showed insignificant differences in MBL (P > 0.05). The difference in periodontal probing depth was not statistically significant when comparing the different groups. The pooled implant survival rates of the different interventions ranged from 88.9% to 100%. The rank probability test showed that 4 bar and 4 telescopic had the lowest MBL, 2 magnet and 2 bar had the highest PI, whereas 4 locator showed the least PPD.

    Conclusions: Except for 4 implants+bar, or telescopic, and 4 locator that, respectively, showed less MBL and PPD compared to some interventions, it seemed that different attachment types and number of implants supporting mandibular ODs have no clear superiority over the other in terms of peri-implant health outcomes.

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  • Tomoshige Kabetani, Shintaro Ban, Atsushi Mine, Takuma Ishihara, Hayak ...
    Type: original article
    Article ID: JPR_D_20_00287
    Published: 2021
    [Advance publication] Released: September 25, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: To analyze the causes of debonding of computer-aided design/computer-aided manufacturing (CAD/CAM) indirect resin composite premolar crowns with a focus on the morphological factors of the crown and abutment teeth.
    Methods: The clinical courses of 109 CAD/CAM indirect resin composite crowns were observed, and the patients’ background characteristics, crown locations, luting methods, types of abutments, distal-most/non-distal-most molars, and types of resin blocks were confirmed. To investigate the influence of the morphology of the crown and abutment teeth, the 1) vertical dimension of the abutment teeth, 2) taper, and 3) thickness of the crown occlusal surface during events were measured from the three-dimensional digital data. The Kaplan–Meier method and multivariable Cox proportional hazard model were used for the statistical analyses. The nonlinearity of the effect of each comparison factor was included in the model.
    Results: Complications included 21 debonding cases, two crown fractures, five root fractures, and two core debondings. The cumulative no-debonding and no-crown-fracture rate over 1423 days (3 years and 11 months) was 77.4%. The multivariable Cox regression analysis revealed that the abutment teeth type of tooth (first or second premolar) (P = 0.02) and luting materials (P < 0.01) significantly influenced the debonding frequency. All morphological factors (1–3) significantly influenced the debonding. The hazard ratios and nonlinear graph indicated that the crown thickness was less effective than the vertical dimension and taper.
    Conclusions: The combination analysis of clinical outcomes and 3D digital data revealed that preparation of the abutment is important for avoiding crown debonding.
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  • Zhongyi Li, Hongqiang Ye, Hefei Bai, Yijiao Zhao, Yong Wang, Yuchun Su ...
    Article ID: JPR_D_20_00320
    Published: 2021
    [Advance publication] Released: September 28, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: Although mock-ups have been widely used in dental esthetic rehabilitation, their accuracy has not been quantitatively evaluated, and the methods of fabricating mock-ups are various. This in vitro study investigated the thickness accuracy of mock-ups fabricated with different silicone matrices.

    Methods: Mock-ups of maxillary anterior teeth were respectively fabricated by 72 silicone matrices that were equally divided into four groups (n=18 for each group) according to two variables of the silicone matrices: labial margin position (equigingival or cover labial gingiva for 1−2 mm) and palatal notches (with or without notches on the palatal side of silicone matrices). The thickness accuracy of the mock-ups was analyzed using 3D scanning and 3D deviation analysis techniques compared with diagnostic waxing. The thickness change ratios of the mock-ups were compared using a two-way analysis of variance (ANOVA). One-way ANOVA and Kruskal-Wallis tests were used to compare differences in thickness change ratios between different teeth in each group.

    Results: The thickness accuracy of the mock-ups was significantly affected by the labial margin position and the palatal notches of the silicone matrices, respectively, in the labial area and the incisal area. The most accurate mock-ups were made using silicone matrices with equigingival labial margins and palatal notches. The thickness accuracy of the mock-ups was also inconsistent on different teeth.

    Conclusions: The mock-ups fabricated by silicone matrices were thicker than the diagnostic waxing. The application of silicone matrices to equigingival labial margins and palatal notches was beneficial to the thickness accuracy of mock-ups.

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  • Moritz Waldecker, Rouven Behnisch, Peter Rammelsberg, Wolfgang Bömicke
    Type: Original article
    Article ID: JPR_D_21_00024
    Published: 2021
    [Advance publication] Released: September 23, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: The purpose of this study was to prospectively evaluate the medium-term clinical performance and esthetics of monolithic and partially (i.e., facially) veneered zirconia single crowns (MZ-SC and PZ-SC, respectively).
    Methods: Between September 2011 and June 2013, 68 participants received 90 MZ-SC and 72 PZ-SC. Clinical study documentation was performed at crown cementation (baseline), at 6-month follow-up, and then yearly thereafter using standardized report forms. Three participants with four MZ-SC dropped out during clinical follow-up. Thus, 65 participants (n = 31, 47.7% men) fitted with 158 restorations (86 MZ-SC, 72 PZ-SC) were evaluated. The mean observation period of the restorations was 5.8 ±2.5 years; 6.3 ±2.2 for MZ-SC and 5.2 ±2.6 for PZ-SC.
    Results: The 5-year rate of complication-free survival (success) was 87.0% for MZ-SC and 95.8% for PZ-SC (log-rank test, p = 0.026). The 5-year failure-free survival rate was 93.1% for MZ-SC and 96.2% for PZ-SC (log-rank test, p = 0.111), and the 5-year ceramic fracture-free survival rate was 100% for MZ-SC and 98.6% for PZ-SC (log-rank test, p = 0.274). Crowns of both designs were awarded excellent scores for esthetics by participants and dentists.
    Conclusions: Monolithic and partially veneered zirconia crowns can be used clinically with high medium-term survival and success and uncompromised esthetic results.
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  • Sebastian Spintzyk, Sophia Brinkmeier, Fabian Huettig, Alexey Unkovski ...
    Article ID: JPR_D_21_00019
    Published: 2021
    [Advance publication] Released: September 18, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Purpose: To assess the bonding between conventional and additively manufactured silicone elastomers and cylindrical retention titanium magnets for anchorage of facial prostheses.

    Methods: The customized titanium retention magnets were embedded in conventional and additively produced silicone blocks without primer application (n = 20) and with two commercially available primers G611 (n = 20) and A304 (n = 20) applied onto the magnet surface. The pull out test was performed in the universal testing machine using 45° and 90° angulation and the pull out strength was measured for each group. Additionally the SEM images of the pulled out magnets’ surface were obtained and the amount of residual silicone onto the magnet surface was quantified.

    Results: Significantly higher pull out strength values (p < 0.05) were revealed for 90° specimens (0.11 – 0.17 ± 0.01 N/mm2) compared to the 45° group (0.03 ± 0.02 N/mm2). The pull out test with primer revealed no significant differences between the G 611 and A 304 primers in the additive group. However, significantly (p < 0,05) higher values were observed for conventional specimens in the A304 group (1.10 ± 0.21 N/mm2) compared to the G611 group (0.59 ± 0.27 N/mm2).

    Conclusion: The application of both used primers may be an acceptable technical option for the anchorage of retention titanium magnets in silicone facial prostheses, produced additively in a fully digital workflow.

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  • Koji Mizutani, Risako Mikami, Akira Tsukui, Shigeyuki Nagai, Verica Pa ...
    Type: Technical report
    Article ID: JPR_D_21_00045
    Published: 2021
    [Advance publication] Released: September 18, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This article describes a novel, minimally invasive procedure called Er:YAG laser micro-keyhole surgery (EL-MIKS) that removes metal or amalgam tattoos in the gingiva adjacent to prosthetic teeth without gingival deformity and recession. We aimed to evaluate the clinical efficacy of EL-MIKS for removing metal tattoos and present its long-term treatment outcomes.
    Methods: The EL-MIKS procedure consists of several steps that are all performed under a microscope. First, a micro-keyhole (1-2 mm diameter) was prepared using an Er:YAG laser in the center of the metal pigmentation. The connective tissue was evaporated in the deep layer, where metal debris was deposited. Second, within the accessible range, the irradiation angle was changed in various directions to ablate the metal pieces and discolored connective tissue without enlarging the keyhole. Finally, after blood filled the space created by the tissue evaporation, the surface of the blood clot at the entrance of the micro-keyhole was thermally coagulated with defocus laser irradiation. Pigmentation that could not be successfully removed from a single micro-keyhole was treated by forming new micro-keyholes at a distance of 3 mm or more from each previously created hole. Depigmentation over an extended area was completed over a few sessions every 4 weeks without gingival recession after surgery.
    Conclusions: EL-MIKS, a novel depigmentation technique, was able to successfully remove an extended area of metal tattoos in the gingiva using a simpler, easier, and less invasive procedure than conventional periodontal plastic surgery. Esthetic restoration was successfully achieved without postoperative alteration of the gingival contour.
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  • Jin Kitani, Futoshi Komine, Kosuke Kusaba, Daishi Nakase, Keigo Ito, H ...
    Type: Original article
    Article ID: JPR_D_21_00055
    Published: 2021
    [Advance publication] Released: September 17, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This study evaluated the influence of firing procedures and layering thickness of porcelain on internal adaptation of maxillary anterior cantilever zirconia resin-bonded fixed dental prostheses (RBFDPs).
    Methods: The maxillary right central incisor on a model was prepared for a single-retainer zirconia RBFDP. A total of 36 frameworks of cantilever zirconia RBFDPs were classified into three groups (CB0.5, CB1.0, and CB2.0 groups) based on the thickness of the cut-back on the facial surface (0.5 mm, 1.0 mm, and 2.0 mm, respectively). Feldspathic porcelain was layered onto the facial surface of the zirconia RBFDP frameworks. Internal space widths between the abutment tooth and the framework were measured before and after porcelain firing by a replica technique. The internal space values before and after porcelain firings were compared using the paired t-test within the same group (α = 0.05). Differences in internal space values (distortion) between before and after porcelain firing were compared using one-way analysis of varianc e and Tukey multiple comparison tests.
    Results: For all framework designs, internal space values after porcelain firing were significantly higher than those before firing. Among all groups, the CB0.5 group showed the lowest internal distortion values for the whole measured area. The CB2.0 group showed higher distortion values than the CB1.0 group.
    Conclusions: Porcelain firing procedures negatively impacted the internal space in cantilever zirconia RBFDPs. In addition, the increased volume of layering porcelain had a negative effect on the internal distortion of ma xillary anterior cantilever zirconia RBFDPs.
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  • Xi Lin, Yan Gao, Xianglong Ding, Xianghuai Zheng
    Type: Review
    Article ID: JPR_D_20_00262
    Published: 2021
    [Advance publication] Released: September 16, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: The aim of the present study was to evaluate the clinical feasibility of the socket shield technique (SST).
    Study selection: An electronic search of the PubMed, Cochrane Central Register of Controlled Trials, and Wiley Online Library databases, and a manual reference search for articles published up to September 2020 was conducted. Meta-analysis was performed to estimate marginal bone loss (MBL), changes in buccal bone width (cBBW), pink esthetic score (PES), implant stability quotient (ISQ), implant failure rate, and complication rate between SST and conventional immediate implant placement (IIP). All pooled analyses were based on random effects models.
    Results: Sixteen relevant studies were ultimately selected by two independent reviewers: four randomized clinical trials (RCTs), four case-control studies, and eight retrospective studies. Meta-analysis revealed a trend toward lower MBL and cBBW and higher PES in the SST group. ISQ, implant failure rate, and complication rate were similar between the groups.
    Conclusions: The included studies provided evidence that SST may be a feasible treatment option. However, this technique should not be used as a routine clinical protocol due to the lack of evidence-based consensus guidelines, large-scale RCTs, and long-term follow-up data. Therefore, there is an urgent need for well-conducted RCTs in this field.
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  • Kotaro Ito, Hirotaka Muraoka, Naohisa Hirahara, Eri Sawada, Shunya Oka ...
    Type: Original article
    Article ID: JPR_D_20_00310
    Published: 2021
    [Advance publication] Released: September 11, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This study aimed to evaluate whether lacunar infarcts can be predicted from occlusal support and periodontal stage on images.
    Methods: Seventy patients with lacunar infarcts and 300 participants without lacunar infarcts who underwent cerebral checkups at our university hospital were retrospectively reviewed. Lacunar infarcts were assessed using magnetic resonance images by a neuroradiologist. The number of teeth, occlusal support, and severity of radiographic bone loss (RBL) were evaluated using computed tomography. Occlusal support was classified according to the Eichner classification. Additionally, patient characteristics were investigated using medical charts and blood test reports. Records of clinical periodontal parameters, such as clinical attachment loss and bleeding on probing, were also evaluated.
    Results: The severity of RBL and Eichner classification in patients with lacunar infarcts was significantly higher than that in individuals without lacunar infarcts (P<.01). Receiver operating characteristic analysis revealed that the cut-off values for predicting lacunar infarct were ≥ III in the severity of RBL and ≥B1 in the Eichner classification. The corresponding areas under the curve were 0.75 and 0.70, respectively. In multivariate analysis, the factors affecting the severity of RBL (≥ III) (odds ratio [OR], 8.1; 95% confidence interval [CI], 4.1–16.3; P ‹.001), and Eichner classification ( ≥B1) (OR, 1.9; 95% CI, 0.86–4.1; P ‹.05) were significantly associated with the occurrence of lacun ar infarcts.
    Conclusions: The severity of RBL and the Eichner classification may be helpful in predicting lacunar infarcts. Therefore, proper periodontal treatment and prosthodontic rehabilitation of missing teeth may prevent lacunar infarcts.
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  • Shin-ichi Masumi, Eri Makihara, Tetsuo Yamamori, Shuji Ohkawa
    Type: Review
    Article ID: JPR_D_21_00035
    Published: 2021
    [Advance publication] Released: September 11, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: To present a clinical rationale for the effectiveness of denture space recording methods for the prosthetic treatment of edentulous patients through a review of the literature.
    Study selection: A total of 3167 studies were extracted from a search of four terms, namely denture space, neutral zone technique, flange technique, and piezography using PubMed and J-STAGE databases. A total of 57 documents that matched the inclusion and exclusion criteria were selected.
    Results: From the extracted articles, the clinical application of denture space recording methods was found to be effective in edentulous patients with severe ridge resorption. The relationship between the labiolingual and buccolingual pressure in patients with neuromuscular problems or with mandibular or lingual defects differs from those without it, so a stable prosthesis ca n be easily fabricated by locating the neutral zone using denture space recording methods.
    Conclusions: The literature on denture space recording methods suggests that its application on challenging cases of edentulous patients is useful in providing prostheses with improved retention and stability.
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  • Simon Peroz, Benedikt Christopher Spies, Ufuk Adali, Florian Beuer, Ch ...
    Article ID: JPR_D_21_00023
    Published: 2021
    [Advance publication] Released: August 28, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
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  • Kana Tokumoto, Aya Kimura-Ono, Takuya Mino, Suguru Osaka, Ken Numoto, ...
    Type: Original article
    Article ID: JPR_D_20_00272
    Published: 2021
    [Advance publication] Released: August 31, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: We aimed to determine root caries annual incidence (RCAI) and root caries annual progression (RCAP) and risk factors for them among older people requiring nursing care.
    Methods: The target population comprised 186 dentate individuals aged ≥ 65 years who required nursing care while living in nursing homes (NHs) or their own homes (OHs) in Okayama, Japan. Survey items included presence/absence and severity of root caries, age, sex, living environment (NH or OH), the Clinical Dementia Rating, and the Barthel Index (BI). Baseline surveys were conducted from 2015 to 2017; subjects were followed up for one year. RCAI and RCAP per tooth and per person were calculated, and risk factors for them were identified using generalized estimating equations.
    Results: In total, 104 individuals (mean age: 82.0 ± 12.4 years) completed the follow-up survey. RCAIs per tooth and per person were 14.6% (173/1188) and 59.6% (62/104), respectively. RCAP per tooth was 22.5% (51/227 teeth with root caries at baseline). Significant risk factors for RCAI were living environment (OH, odds ratio [OR]: 2.14), sex (male, OR: 1.84), clasped tooth (OR: 1.82), and older age (OR: 1.05) at baseline. Significant risk factors for RCAP were sex (male, OR: 5.20), regular dental checkup (OR: 2.74), and high BI score (OR: 1.02) at baseline.
    Conclusions: At one-year follow-up, 59.6% of the subjects developed at least one root caries. Risk factors for RCAI were living environment (OH), male, clasped tooth, and older age, whereas those for RCAP were male, regular dental checkup, and high BI score.
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  • Keiko Nakamura, Tomohiro Kawaguchi, Hiroshi Ikeda, Pirat Karntiang, Ka ...
    Type: Original article
    Article ID: JPR_D_20_00297
    Published: 2021
    [Advance publication] Released: August 31, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: Screw-retained implant crowns used as dental implants comprise a zirconia coping and titanium base bonded using resin cement. These devices are prone to debonding failures. This study investigated the bond characteristics of implant materials based on shear bond strength (SBS) and surface characteristics.
    Methods: Chemically pure (CP) titanium grade-4 (Ti), Ti-6Al-4V alloy (Ti-6Al-4V), and tetragonal polycrystalline zirconia (zirconia) were evaluated as adherent materials. Plates of each material were polished, primed for the respective resin cements, and cemented using either methyl methacrylate-based resin cement (Super-Bond) or composite-based resin cement (Panavia). The cemented samples were subjected to 10,000 thermocycles alternating between 5 and 55 °C, and the SBS were obtained before and after thermocycling. The sample surfaces were characterized based on surface observations, roughness, and free energy (SFE).
    Results: The SBSs of all materials bonded using Panavia were significantly compromised during thermocycling and reached zero. Although the SBSs of Ti and Ti-6Al-4V bonded using Super-Bond were not significantly affected by thermocycling, those of zirconia decreased significantly. The bond durability between zirconia and Super-Bond was improved via alumina air-abrasion, which caused no significant loss of SBS after thermocycling. Surface analyses of the air-abraded zirconia validated these results and confirmed that its surface roughness and SFE were significantly increased.
    Conclusions: The bond durability between resin cement and zirconia was lower than that between Ti and Ti-6Al-4V. The alumina air-abrasion pretreatment of zirconia improved the SFE and surface roughness, thereby enhancing bond durability.
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  • Akinori Tasaka, Franz Sebastian Schwindling, Stefan Rues, Peter Rammel ...
    Type: Original article
    Article ID: JPR_D_20_00163
    Published: 2021
    [Advance publication] Released: August 04, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This study investigated changes in the retentive force of telescopic crowns fabricated by combining a zirconia primary crown and a fiber-reinforced composite (FRC) secondary crown.
    Methods: Primary zirconia crowns were produced with a nominal convergence angle of 0°. Forty-eight secondary crowns were milled from FRC and divided into three study groups (n=16/group) based on milling parameters and post-milling adjustment. The offset parameter used for the final milling step of the inner crown surface was adjusted for a tight initial fit in Group 1 (milling offset: +10 µm, i.e., 2 × 10 µm = 20 µm lower inner diameter compared with the CAD file of the crown) and for improved initial fit (milling offset: -10 µm, i.e., an enlargement of the inner crown diameter by 2 × 20 µm = 40 µm in relation to Group 1) in Groups 2 and 3. The inner surfaces of the secondary crowns were polished with diamond paste in Groups 1 and 2, and silicon points were used for Group 3. The retentive force was measured using a universal testing device. The secondary crown was placed on the primary crown, with the final fitting force set to a load of 100 N. This test was conducted before and after aging (10,000 insertion/removal cycles) under dry and wet conditions. A generalized linear model was used to estimate the differences in the retentive force to elucidate the effects of the milling parameters and polishing methods.
    Results: We realized an initial retentive force of approximately 10 N. In Groups 2 and 3, the difference was statistically significant between the dry and wet conditions before aging (P < 0.05). There was no significant difference between the dry and wet conditions after aging in any of the groups (P > 0.05).
    Conclusions: An adequate initial retentive force can be achieved with telescopic crowns combining zirconia and FRC.
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  • Duo Wang, Jianxiang Tao, Anqi Jin, Hongbo Yu
    Type: Original article
    Article ID: JPR_D_20_00281
    Published: 2021
    [Advance publication] Released: August 04, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This study aimed to investigate the cortical response characteristics evoked by natural teeth and implants.
    Methods: Five cats were subjected to intrinsic signal optical imaging to measure the cortical responses evoked by natural teeth and implants. The difference in tactile sensation between the implant and natural tooth was compared in detail at the cortical response level.
    Results: Some similarities were observed between the implants and natural teeth. The stimulating-response curves of the implants and natural teeth were generally S-curves, and both implants and natural teeth preferred labial-lingual direction stimulation. The implants and natural teeth differed in terms of their tactile sensitivity: implants were weaker than natural teeth in terms of both static and dynamic sensitivity. However, after saturation, there was no significant difference in tactile strength between implants and natural teeth.
    Conclusions: Both natural teeth and implants are able to distinguish the tactile strength and stimulation direction. Although implants are less sensitive than the natural tooth, the maximal tactile function and directional preference of implants are similar to those of natural teeth.
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  • Dai Imai, Atsushi Mine, Ryoma Ezaki, Hayaki Nakatani, Mariko Matsumoto ...
    Type: Original article
    Article ID: JPR_D_21_00015
    Published: 2021
    [Advance publication] Released: August 04, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This study examined four cleaning methods and three chemical treatments for artificial saliva-contaminated fiber posts in terms of bonding durability to resin composite core materials.
    Methods: Non-contaminated fiber posts (Tokuyama FR Post, Tokuyama Dental) and those contaminated (GC Fiber Post, GC) with artificial saliva (Saliveht Aerosol, Teijin Pharma) were used. Washing and drying (WD), alcohol cleaning (AlC), H3PO4 etching (P/WD), alumina blasting (B/D) for decontamination and silanization (Clearfil Ceramic Primer Plus, Kuraray Noritake Dental, Si), resin priming (HC Primer, Shofu, MMA), and bonding resin application (Clearfil Universal Bond Quick, Kuraray Noritake Dental, BR) for chemical treatment were performed. The treated fiber post was planted inside a cylindrical tube and filled with resin composite (DC Core Automix ONE, Kuraray Noritake Dental). The specimen was sectioned, and a push-out test was performed after 24 h, 1 month, and 3 months. The fracture surface was observed using a scanning electron microscope (SEM).
    Results: Adhesion between the non-contaminated fiber post and resin composite did not improve by silanization and decreased by alumina blasting. SEM observations revealed a fractured glass fiber by alumina blasting. Saliva contamination decreased the bond strength between the fiber post and resin composite; however, recovery was achieved by WD, Alc, P/WD, and B/D. Compared to Si, BR (P = 0.009) was effective in restraining the long-term durability of bonding, whereas MMA (P = 0.99) was not.
    Conclusions: The application of bonding resin after alcohol cleaning is the most convenient and effective clinical procedure for fiber post surface treatment.
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  • Takuya Kihara, Tomoko Ikawa, Yuko Shigeta, Shuji Shigemoto, Keisuke Ih ...
    Type: Original article
    Article ID: JPR_D_20_00103
    Published: 2021
    [Advance publication] Released: July 29, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: The purpose of this study was to examine the wear of resin materials using two-body wear tests and to verify a selection method for optimal interim restoration materials from findings of a diagnostic occlusal dev ice.
    Methods: Specimens were prepared from nine different resins used for diagnostic occlusal devices (soft resin) and interim restorations. Wear tests were conducted using an abrasion testing machine. The resulting wear on resin specimens and antagonist stainless-steel styluses was measured using a laser confocal scanning microscope, and the surface conditions were observed through a scanning electron microscope. The data were analyzed with one-way ANOVA and Tukey’s multiple comparison test. The findings of the previous study on diagnostic occlusal devices were referred to in order to verify the selection method of optimal interim restoration materials.
    Results: The maximum wear depth of the soft resin specimens was significantly greater than that of the other specimens (p<0.05) and was equivalent to the wear depth of a diagnostic occlusal device used for 14 nights. The wear of bis-acryl resin material was shallower than that of the other materials (Polymethyl methacrylate and polyethyl methacrylate), and its antagonist stylus was significantly worn (p<0.05).
    Conclusions: The findings of the previous and present studies showed a relationship among the parameters of Electromyography, wear depth of the diagnostic occlusal device, and wear of materials used for interim restorations. Findings related to bruxism can guide in the selection of interim restoration material and the determination of a suitable duration of wear.
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  • Shogo Iwaguro, Saiji Shimoe, Hiroto Takenaka, Yuki Wakabayashi, Tzu-Yu ...
    Type: Original article
    Article ID: JPR_D_20_00197
    Published: 2021
    [Advance publication] Released: July 29, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: Zirconia cores and frameworks are widely used in restorative dentistry. Although these structures are veneered with porcelain for esthetic reasons, the use of indirect composite resins (ICRs) is expected to increase in the future. The purpose of this study was to investigate the effects of microslits of different dimensions formed by Nd:YVO 4 laser machining on the bond strength between two types of zirconia (3 mol% yttria-partially stabilized zirconia (Y-TZP) and ceria-partially stabilized zirconia/alumina nanocomposite (Ce-TZP/A)) and porcelain or an ICR.
    Methods: The zirconia disks were assigned as follows: 1) blasted with alumina particles (AB) and 2–4) surface machined with gridded microslits with a width, pitch, and depth of 50, 75, or 100 µm (MS50, MS75, and MS100, respectively). After the bonding of the veneering materials to the disks, half of the specimens veneered with the ICR were subjected to thermocycling (4–60°C, 20000 cycles). All the specimens were subsequently shear tested (n = 10/group).
    Results: There was no significant difference between the groups of the disks bonded to porcelain. On the other hand, for the disks bonded to the ICR, the bond strengths of the MS groups after thermocycling were statistically higher than that of the AB group. However, there was no significant difference in the bond strengths of the disks with different microslits.
    Conclusions: Within the study limitations, it can be concluded that, for porcelain, the design of the mechanical retentive structure must be modified. However, for the investigated ICR, a simple gridded pattern can improve the bond strength with zirconia.
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  • Morakot Piemjai, Noppawan Adunphichet
    Type: Original article
    Article ID: JPR_D_20_00249
    Published: 2021
    [Advance publication] Released: July 29, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: To compare the effect of 4-META/MMA-TBB resin, which can provide hybrid layer formation, and acid-base cements on survival, complications, and failure risks of full-coverage retainers evaluated for 15 years.
    Methods: A total of 1,161 abutment teeth in 260 patients treated with at least one single crown or fixed partial denture were recalled for clinical examination. Survival was defined as not having undergone extraction of abutments or renewal of prostheses. Secondary caries, pulp necrosis, or prosthesis detachment were recorded as complications. Survival and complications rates were analyzed using the Kaplan–Meier method and log-rank test. Multivariable analysis of factors associated with failure or complications using Cox's proportional hazard regression model was performed (α = 0.05).
    Results: Significant differences were observed in survival ( p = 0.007), secondary caries (p = 0.000), and prosthesis detachment (p = 0.025) complications between luting agents. The 5-, 10-, and 15-year survival rates for 4-META/MMA-TBB resin were 95.2%, 90.5%, and 90.5%, while those of acid-base cements were 93.2%, 80.6, and 67.4%, respectively. Secondary caries and prosthesis detachment complications for 4-META/MMA-TBB resin were 1.9% and 0.5%, whereas those for acid-base cements were 15.2% and 4.3% respectively. Acid-base cements were associated with a 1.664-, 2.950-, 3.333-, and 4.444-times greater risk of failure, prosthesis renewal, secondary caries and prosthesis detachment, respectively.
    Conclusions: 4-META/MMA-TBB resin has higher long-term survival rate with lesser caries and prosthesis detachment than acid-base cements. The ability of this resin to create an acid-base resistant hybrid layer may contribute to a life-long function of tooth abutment.
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  • Shoko Miura, Shohei Tsukada, Takafumi Fujita, Tomonori Isogai, Daisuke ...
    Type: Original article
    Article ID: JPR_D_21_00025
    Published: 2021
    [Advance publication] Released: July 29, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This study aimed to evaluate the effects of the tooth portion evaluated and the colors of the abutment tooth and resin luting agent on the final color of monolithic zirconia crowns.
    Methods: Monolithic zirconia crowns were fabricated for left maxillary central incisors using two shades (A2 and A3) of highly translucent monolithic zirconia disks. A model of the abutment tooth was fabricated using resin core materials (white: W; dentin: D). The color of the crowns was measured with try-in pastes (clear: C; brown: B) as a resin-luting agent substitute. The measurement was performed after placing the crown on the model with the attached abutment tooth with try-in paste. The color of three labial portions (cervical, body, and incisal) was evaluated using a dental spectrophotometer. The color difference (ΔE) between the CIELab values of the zirconia disks and the final me asurement of zirconia crowns was calculated.
    Results: The ΔE between the crown of the A2 shade and the zirconia disk of the A2 shade had the highest ΔE value in the body portion with W-B (ΔE=3.92). Similarly, the A3 shade had the highest ΔE value in the cervical portion, with W-B (ΔE=4.27). The results of three-way ANOVA showed that the ΔE values were influenced by the tooth portion evaluated and the color of the abutment tooth.
    Conclusions: The final color of the monolithic zirconia crowns was significantly in fluenced by the tooth portion evaluated and the color of the abutment tooth.
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  • Laura Christine Leisner, Akinori Tasaka, Charlotte Theresa Trebing, Ti ...
    Type: Original article
    Article ID: JPR_D_20_00110
    Published: 2021
    [Advance publication] Released: July 21, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: High-definition cone-beam computed tomography (HD-CBCT) offers superior image quality at the cost of higher radiation dose compared to low-dose CBCT (LD-CBCT). The aim of this study was to investigate whether peri-implant bone lesions can be accurately quantified using LD-CBCT, even when including the influence of surrounding tissues.
    Methods: Twelve titanium implants restored with all-ceramic crowns were placed in bovine bone, and peri-implant lesions were prepared. Radiographic imaging was performed using IR (intraoral radiography), HD-CBCT and LD-CBCT. To simulate the in-vivo situation, the samples were placed inside a dry human mandible, and a second LD-CBCT imaging was performed (LD-CBCT*). The datasets were presented to four observers in random order. Maximum lesion depth and width were measured in a standardized mesiodistal slice in IR, HD-CBCT, LD-CBCT, and LD-CBCT*. Mean lesion depth and width measurements for each sample in HD-CBCT served as reference.
    Results: Interrater agreement was slight for depth and excellent for width in HD-CBCT and both LD modes. For all observers, measurement deviations from HD-CBCT were below 0.3 mm in the LD protocols (LD-CBCT depth: 0.22 ± 0.17 mm, width: 0.22 ± 0.13 mm; LD-CBCT* depth: 0.24 ± 0.23 mm, width: 0.25 ± 0.21 mm) and at 0.4 mm in IR.
    Conclusions: Absolute differences between LD-CBCT and HD-CBCT are small, although surrounding tissues decrease LD-CBCT image quality. Within the limitations of an in-vitro trial, LD-CBCT may become an adequate imaging modality for monitoring peri-implant lesions at a substantially decreased radiation dose.
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  • Asuka Murakami, Tetsuya Hara, Chie Yamada-Kubota, Miho Kuwahara, Tomok ...
    Type: Original article
    Article ID: JPR_D_20_00205
    Published: 2021
    [Advance publication] Released: July 21, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: The lack of occlusal support is an epidemiological risk factor linked to Alzheimer's disease. This study sought to assess the relationship between amyloid β (Aβ) deposition and the lack of occlusal support in amyloid precursor protein (APP) knock-in mice.
    Methods: Sixteen experimental animals were divided into two groups. The upper molars were extracted in the extraction group (group E), and a sham operation was performed in the control group (group C). The Morris water maze test was performed 4 months after the tooth extraction. Aβ immunohistochemical staining and Nissl staining of the hippocampus were performed. Hippocampal plasma corticosterone and Aβ protein levels were measured.
    Results: In the maze task, the escape latency was significantly longer in group E than in group C. In the probe trials, the time elapsed in the target quadrant was significantly shorter in group E than in group C. The number of hippocampal neurons decreased in group E. There was no significant difference in the plasma corticosterone levels between the two groups, indicating that there was no effect of chronic stress on the behavioral results. Hippocampal Aβ40 and Aβ42 protein levels and Aβ deposition areas by immunohistochemical staining were not significantly different between the two groups.
    Conclusions: Aβ deposition was not increased in the hippocampus of molarless APP knock-in mice. As such, it appears that cognitive impairment due to a lack of occlusal support was not related to Aβ deposition.
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  • Ryoma Ezaki, Atsushi Mine, Kazuhisa Sato, Ken-ichi Fukui, Keigo Kumada ...
    Type: Original article
    Article ID: JPR_D_20_00260
    Published: 2021
    [Advance publication] Released: July 21, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: This study aims to confirm the usefulness of active acoustic emission (Active AE) for reproducible and non-invasive generation of physical external force which is required for conventional AE.
    Methods: Experiment 1: A root dentin-resin adhesive interface was observed. The post space was filled with a dual-cure resin composite core material with and without adhesive. The vibration characteristics of the data obtained from the time-frequency analysis were evaluated. Experiment 2: A crown-abutment tooth adhesive interface was observed. Adhesive resin cement was used for luting the crown and adhesion states in the same specimen over time were analyzed with three measurements: at trial-fitting, immediately after luting, and 2 weeks after luting. Data were subjected to time-frequency analysis and relationships between amplitude (indicating loudness) and frequency (indicating the sound component) were analyzed.
    Results: Experiment 1: Time-frequency analysis confirmed multiple peak frequencies for each specimen without adhesive and monomodal peak frequency in all specimens using adhesive. Experiment 2: Two weeks after luting, all specimens showed a single major peak except one which showed multiple weak peaks.The three-dimensional visualization of time-frequency analysis revealed one specimen with multiple weak peaks while all others displayed a single, low-amplitude band at 2 weeks after luting.
    Conclusions: The state of the adhesive interface can be evaluated using active AE. This basic technique may prove useful to evaluate changes in the adhesive interface of prostheses over time.
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  • Franz Sebastian Schwindling, Kevin Nikolas Bechtel, Andreas Zenthöfer, ...
    Type: Original article
    Article ID: JPR_D_20_00321
    Published: 2021
    [Advance publication] Released: July 21, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: Fabrication inaccuracies can compromise the fit of large-span monolithic zirconia restorations. Sintering distortion is a particular problem. This study aimed to assess the fit of full-arch restorations made from mono lithic zirconia for different abutment configurations.
    Methods: To quantify fit inaccuracies created during the fabrication of experimental large-span restorations, an in-vitro model with eight abutment teeth was equipped with strain gauges. Ten 14-unit restorations were made from monolithic zirconia and seated on the model in turn. For each of the ten restorations, measurements were taken for three different abutment configurations—polygonal, quadrangular, and unilaterally shortened. Strains exerted during seating were recorded in the anterior-posterior and buccal-palatal directions, and the resulting horizontal forces (rhF) were calculated along with the respective abutment deflection (ad). Data were analyzed using Kruskal–Wallis tests at a significance level of 0.05.
    Results: All restorations could be seated on the multi-abutment model. The restorations exhibited fabrication misfits, tending to be too wide. Mean rhF/ad were largest for the quadrangular configuration (16.8±2.9 N/0.065 mm) and smallest for the polygonal configuration (13.6±4.5 N/0.053 mm). The largest rhF/ad were measured on abutments of the unilaterally shortened configuration, with a maximum deflection of 0.126 mm. For two of three configurations, rhF/ad were significantly larger for the distal abutments than for the other abutments.
    Conclusions: Even if milling and sintering procedures are optimum, misfit-induced horizontal forces cannot be avoided. Because of the natural tooth mobility, however, the fit of full-arch restorations made from monolithic zirconia might be clinically acceptable.
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  • Sahar Hussein, Rifat Falak Kantawalla, Stephenie Dickie, Piedad Suarez ...
    Type: Review
    Article ID: JPR_D_20_00207
    Published: 2021
    [Advance publication] Released: July 15, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Supplementary material
    Purpose: To evaluate whether poor oral health is associated with a higher risk of malnutrition based on the Mini Nutritional Assessment (MNA) or MNA-SF (short form) in older adults.
    Study Selection: For this meta-analysis, cohort and cross-sectional studies with adults 65 years and older, reporting oral health outcomes (i.e. edentulism, number of teeth) and either the MNA or MNA-SF were selected. Four electronic databases were searched (Medline via PubMed, Web of Science, Cochrane Library and EMBASE) through June 2020. Risk of bias was assessed with the checklist by the Agency for Healthcare Research and Quality scale.
    Results: A total of 928 abstracts were reviewed with 33 studies, comprising 27,559 participants, aged ≥65 being ultimately included. Meta-analyses showed that the lack of daily oral hygiene (teeth or denture cleaning), chewing problems and being partially/fully edentulous, put older adults at higher risk of malnutrition (p < 0.05). After adjustment for socio-demographic variables, the included studies reported lack of autonomy for oral care, poor/moderate oral health, no access to the dentist and being edentulous with either no dentures or only one denture were risk factors significantly associated with a higher risk of malnutrition (p < 0.05).
    Conclusions: These findings may imply that once elders become dependent on others for assistance with oral care, have decreased access to oral healthcare, and lack efficient chewing capacity, there is increased risk of malnourishment. Limitations of the study include heterogeneity of oral health variables and the observational nature of the studies. Further studies are needed to validate our findings.
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  • Hiroaki Nagatsuka, Shigehisa Kawakami, Miho Kuwahara, Chie Kubota, Nao ...
    Type: Original article
    Article ID: JPR_D_20_00230
    Published: 2021
    [Advance publication] Released: July 15, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Purpose: To design an efficient tongue prosthesis with reproducibility and to objectively evaluate improvement in speech function.
    Methods: A silicon anatomical artificial tongue (AT) and a flat surface artificial tongue system (FTS) were used in our study. Twenty healthy participants (10 males and 10 females, 26.3 ± 1.8 years) were fitted with a tongue movement suppression appliance (TSA) that fit the dental arch to simulate the glossectomy condition. TSA, TSA + FTS, and TSA + AT simulated the state of glossectomy patients without artificial tongue, with normal artificial tongue, and newly designed artificial tongue, respectively. Three speech intelligibility tests were performed for each of the following conditions: pronouncing 100 Japanese monosyllables, 40 Japanese words, and reading a short story. One-way ANOVA, Wilcoxon signed-rank test, and Tukey-Kramer post-hoc test were used for statistical analyses.
    Results: Significant differences were observed for 100 Japanese monosylla bles and 40 Japanese words between the TSA + FTS, TSA, and TSA + AT conditions (p ‹ 0.05). Regarding the speech intelligibility test for reading a short story, the TSA + FTS condition resulted in a significantly higher speech intelligibility than the TSA and TSA + AT conditions (p ‹ 0.05).
    Conclusions: A flat surface artificial tongue system contributed to the improvement in speech function. This structure can be easily used in cases where conventional artificial tongue are applicable, regardless of variation in the oral condition; thus, making it a widely applicable treatment option for glossectomy patients.
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  • Hanako Suenaga, Masahiro Iikubo, Toru Tamahara, Mina Dodo, Chris Peck, ...
    Type: Case Report
    Article ID: JPR_D_20_00270
    Published: 2021
    [Advance publication] Released: July 15, 2021
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Patient: A 33-year-old man diagnosed with extranodal natural killer cell/T-cell lymphoma, nasal type (ENKTCL-NT) inducing palatal perforation was referred to the perioperative oral care support center of Tohoku University Hospital for dental care to support cancer treatment including chemotherapy and hematopoietic stem cell transplantation (HSCT). Dental review during chemotherapy revealed mucositis suspected to be caused by mucosal trauma from altered jaw function (chewing and speech) due to palatal perforation. Although the patient was already in the cleanroom, an oral appliance as well as conservative care as recommended in oral management guidelines for HSCT were used to prevent worsening of oral mucositis at subsequent HSCT including High-dose chemotherapy and total body irradiation. After HSCT, a prosthodontist fitted a palatal obturator made by a dental technician and an oral surgeon reviewed the necrotic bone and removed the sequestra according to the changes in the palate. This approach involving a multidisciplinary team including a hematologist improved the impaired oral function and minimized oral complications .
    Discussion: ENKTCL-NT and its treatment have a significant impact on patients’ oral status. Hence, it is important to provide customized dental care based on previously endorsed guidelines according to the type of disease, treatment requirements, and oral and systemic status.
    Conclusions: This report indicated the importance of dental care with a customized plan before, during, and after HSCT for ENKTCL-NT with multidisciplinary supportive care for cancer patients to improve the impaired oral function and to minimize oral complications.
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