Journal of Prosthodontic Research
Online ISSN : 1883-9207
Print ISSN : 1883-1958
ISSN-L : 1883-1958
最新号
選択された号の論文の21件中1~21を表示しています
Review Articles
  • Hironobu Nishihara, Mireia Haro Adanez, Wael Att
    2019 年 63 巻 1 号 p. 1-14
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: This systematic review aimed to provide an overview of zirconia implants as well as regarding the outcome of the implant-restorative complex in preclinical studies.

    Study selection: An electronic search of the literature prior to July 2017 was performed to identify all articles related to preclinical research on zirconia implants. The search was conducted using MEDLINE (National Library of Medicine) and PubMed without restrictions concerning the date of publication. The search terminology included: zirconia implant, osseointegration, bone-to-implant contact, soft tissue, histology, histomorphometry, surface modification, surface roughness, surface characteristics, and restoration (connecting multiple keywords with AND, OR).

    Results: Fifty-seven studies were finally selected from an initial yield of 654 titles, and the data were extracted. The identified preclinical studies focused on several aspects related to zirconia implants, namely biocompatibility, mechanical properties, implant design, osseointegration capacity, soft tissue response, and restorative options. Due to heterogeneity of the studies, a meta-analysis was not possible. The most frequently used zirconia material for the fabrication of implants is yttria-stabilized tetragonal zirconia polycrystal. The resistance-to-fracture for zirconia implants ranged between 516–2044 N. The mostly investigated parameter was osseointegration, which is compared to that of titanium. A lack of evidence was found with other parameters.

    Conclusions: Due to its good biocompatibility as well as favorable physical and mechanical properties, zirconia implants are a potential alternative to titanium implants. However, knowledge regarding the implant-restorative complex and related aspects is still immature to recommend its application for daily practice.

  • Fabrizio Di Francesco, Gennaro De Marco, Ugo Antonello Gironi Carneval ...
    2019 年 63 巻 1 号 p. 15-24
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: The number of implants needed to support a maxillary overdenture is still a controversial issue. The aim of this systematic review was to investigate the number of implants required to support a maxillary overdenture in order to obtain optimal treatment outcomes in terms of implant survival, overdenture longevity and patient satisfaction.

    Study selection: Pubmed and EMBASE databes were systematically searched and complemented by hand searching from 2000 to 2017. The Prisma statement and a PICOS approach were adopted. All selected articles provided at least two-year follow-up and 10 totally edentulous patients. Survival rate of implants and overdentures were statistically analyzed according to number of implants and according to splitting technique, employing non-parametric Fisher Test for unpaired data. For the pooled analysis of implant failures, the odds ratio between group of 4 splinted implants and group of more than 4 splinted was calculated.

    Results: A total of 28 articles were included. Data analysis of the included studies showed that the survival rate of implants appeared higher in ≥ 4 implants group, whereas the high survival rate of overdentures and patient satisfaction were not significantly influenced by the number of implants.

    Conclusions: The findings of our analysis indicate that overall the most frequent tendency is to place at least four implants, splinted or unsplinted, in order to ensure a higher survival rate of implants. However, the relationship between overdenture survival, the patient's quality of life, and the number of implants required to support a maxillary overdenture has yet to be clarified.

Original Articles
  • Ji-Young Sim, Yeon Jang, Woong-Chul Kim, Hae-Young Kim, Dong-Hwan Lee, ...
    2019 年 63 巻 1 号 p. 25-30
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: This study aimed to evaluate and compare the accuracy.

    Methods: A reference model was prepared with three prepared teeth for three types of restorations: single crown, 3-unit bridge, and inlay. Stone models were fabricated from conventional impressions. Digital impressions of the reference model were created using an intraoral scanner (digital models). Physical models were fabricated using a three-dimensional (3D) printer. Reference, stone, and 3D printed models were subsequently scanned using an industrial optical scanner; files were exported in a stereolithography file format. All datasets were superimposed using 3D analysis software to evaluate the accuracy of the complete arch and trueness of the preparations. One-way and two-way analyses of variance (ANOVA) were performed to compare the accuracy among the three model groups and evaluate the trueness among the three types of preparation.

    Results: For the complete arch, significant intergroup differences in precision were observed for the three groups (p <.001). However, no significant difference in trueness was found between the stone and digital models (p >.05). 3D printed models had the poorest accuracy. A two-way ANOVA revealed significant differences in trueness among the model groups (p <.001) and types of preparation (p <.001).

    Conclusions: Digital models had smaller root mean square values of trueness of the complete arch and preparations than stone models. However, the accuracy of the complete arch and trueness of the preparations of 3D printed models were inferior to those of the other groups.

  • Keiichiro Sagawa, Hiroyasu Furuya, Yuki Ohara, Mitsuyoshi Yoshida, Hir ...
    2019 年 63 巻 1 号 p. 31-34
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: The aim of this study was to determine the influences of oral motor function such as tongue function and bite force on masticatory performance in the elderly.

    Methods: We randomly selected 245 subjects who has 28 natural teeth among community-dwelling elderly. We evaluated masticatory performance using a gummy jelly, and also measured bite force, tongue muscle force, and the speed of tongue movement.

    Results: We found that reduced masticatory performance to be associated with decreased the speed of tongue movement and/or tongue muscle force, indicating that reduced oral motor function also influences masticatory performance.

    Conclusions: These results suggest that keeping oral motor function, as well as maintenance of occlusal support, to be important for maintaining masticatory function in the elderly.

  • Kazuhiko Kaneda, Yusuke Kondo, Chihiro Masaki, Taro Mukaibo, Shintaro ...
    2019 年 63 巻 1 号 p. 35-39
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: To evaluate the long-term clinical results of and risk factors for immediate-loading implant treatment of completely edentulous mandibles.

    Methods: We retrospectively studied 220 implants in 52 patients who received immediate-loading implants in fully edentulous mandibles. Kaplan–Meier survival analyses, log-rank tests, and multilevel mixed-effects parametric survival analysis was used for statistical analyses.

    Results: Thirteen of implants in seven patients failed, and the 10-year cumulative implant survival rate was 93.9 % and significantly (p = 0.049) higher in women than in men. None of the predictor variables were significantly associated with implant survival, although sex tended to be associated with implant survival.

    Conclusions: Immediate-loading implant treatment for completely edentulous mandibles had acceptable clinical results in the long term. Although we could not identify significant risk factors, we established a multilevel mixed-effects parametric survival analysis with the immediate-loading implant survival data.

  • Rinet Dauti, Barbara Cvikl, Bledar Lilaj, Patrick Heimel, Andreas Mori ...
    2019 年 63 巻 1 号 p. 40-46
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: Purpose of this study was to evaluate the accuracy of fit of cemented polymer infiltrated ceramic network (PICN) material crowns manufactured after digital and conventional impression techniques using micro computed tomography (CT). Furthermore to determine the cement space volume and porosities in the cement layer.

    Methods: A molar typodont tooth was prepared for PICN material crowns and replicated thirty times. The dies were randomly divided into three groups of 10 specimens each according to the impression technique: 3M True Definition Scanner (TDS), cara TRIOS (Trios) and Impregum Penta Soft (Impregum). PICN material crowns were milled for each specimen from Vita Enamic blocks and cemented on their respective dies. The absolute marginal discrepancy (AMD), internal fit (IG), total cement space volume (TVC) and marginal porosities (VP) were measured using Micro-CT.

    Results: Mean and standard deviations values in μm for the AMD were: TDS 140.1 (28.4); Trios 253.7 (56.8); Impregum 220.2 (101.1). IG values in μm: TDS 173.1 (27.7); Trios 222.2 (22.4); Impregum 211.6 (55.9). TVC in mm3: TDS 19.82 (2.9); Trios 23.67 (2.01); Impregum 23.77 (5.09). VP in mm3: TDS 0.38 (0.09); Trios 0.36 (0.10); Impregum 0.51 (0.31).

    Conclusions: TDS group showed significantly better marginal and internal fit than the Trios group. No difference of the parameters was detected between the Impregum and both digital groups which implies that the digital impression technique is suitable in the manufacturing process of PICN material crowns.

  • M.M.M. Michelon, A.T. Posch, H.R. Sampaio-Filho, E.J.V. Lourenco, D.M. ...
    2019 年 63 巻 1 号 p. 47-51
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: The purpose of this in vitro study was to compare the stability of removable implant-supported maxillary overdentures with fixed complete dentures and conventional dentures.

    Methods: Four types of complete dentures were tested: conventional complete dentures; overdentures retained by a male resilient attachment system; overdentures retained by a combination of clip bar and attachment system; and fixed complete dentures. Each group was placed in the posterior and anterior region and the stability was recorded by measuring the vertical displacement of the prosthesis.

    Results: There was a difference in the vertical movement of the prosthesis according to the type of system. The results showed that the behavior of the overdenture retained by a combination of a clip bar and attachment system is comparable with the stabilization of an implant-retained fixed complete denture.

    Conclusions: Overdentures retained by a combination of a clip bar and attachment presented better stability and retention capacity under our experimental conditions, close to that of the positive control (fixed complete denture), with the advantages of removable overdentures.

  • Hiroki Tsuka, Koji Morita, Kan Kato, Hitomi Kimura, Hitoshi Abekura, I ...
    2019 年 63 巻 1 号 p. 52-57
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: The mechanical properties of polyetheretherketone (PEEK) are ideally suited for fixed dental prostheses. However, PEEK typically has low adhesion strength to resin-based luting agent. This study assessed the shear bond strength between laser groove treated PEEK and resin-based luting agent.

    Methods: A total of 230 specimens were randomly divided into five groups (n = 46): no-treatment, air abrasion treatment, 100 μm-deep, 150 μm-deep, and 200 μm-deep laser groove treatments. The surface roughness was measured, scanning electron microscopy was used to observe the specimen surfaces, and X-ray photoelectron spectroscopy (XPS) was used to analyze the surfaces. Each group was divided into four resin-based luting agent subgroups: Panavia V5, RelyX Ultimate Resin Cement, G-CEM Link Force, and Super-Bond C&B. After the resin-based luting agent was bonded to the specimens, the bond strength was measured using shear tests and the failure modes were assessed by stereomicroscopy. The surfaces were also observed by scanning electron microscopy (SEM) after the shear bond strength measurements. The data were statistically analyzed using a two-way analysis of variance and Tukey's honest significant difference test (α = 0.05).

    Results: The PEEK surface after laser groove treatment groups exhibited the highest mean Ra values. In the XPS analysis, the laser treated PEEK surface exhibited an effective surface composition for bonding with resin-based luting agent. The shear bond strengths for the laser groove treated samples were significantly higher (p < 0.05) than those of the no-treatment and air abrasion treatment groups.

    Conclusions: The shear bond strength between PEEK and resin-based luting agent was substantially improved by laser groove treatment.

  • Fa-Bing Tan, Jin-Lin Song, Chao Wang, Yu-Bo Fan, Hong-Wei Dai
    2019 年 63 巻 1 号 p. 58-65
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: This study aimed to investigate the effects of selective laser melting (SLM), milling methods, and casting on the behavior of titanium clasp.

    Methods: The clasp and its die simulating the molar were designed using 3D software. Clasp specimens were fabricated using SLM approaches (SLM Ti) and computerized numerical control (CNC) milling technology (Milling CPTi). Cast clasps of the same forms were also prepared as controls using titanium alloy powder (Cast Ti) and commercial pure titanium (Cast CPTi), following the conventional casting methods. The surface roughness and accuracy of clasps were analyzed. The changes in retentive force and permanent deformation were measured up to 10,000 insertion/removal cycles. One-way analysis of variance and Tukey's test or Kruskal–Wallis H test were performed for data analysis and comparisons.

    Results: The Milling CPTi clasps had a smoother inner surface than the other groups (p < 0.05). The accuracy of the inner surface showed no significant difference among the groups, whereas that of the outer surface showed significant differences (p < 0.05). The SLM Ti clasp had significantly higher retentive forces than the other groups (p < 0.05), but it rapidly reduced after 2000 insertion/removal cycles until the fracture of all specimens was at 4000 cycles. The Milling CPTi clasps had more permanent deformation, but the rate of reduction of retentive force was only 9.5% (at 10,000 cycles).

    Conclusions: Milling has the potential to replace casting for fabricating removable partial denture (RPD) titanium clasps. However, SLM should be further improved for fabricating RPD titanium clasps before clinical application.

  • Ayumi Matsuoka, Fumi Yoshioka, Shogo Ozawa, Jun Takebe
    2019 年 63 巻 1 号 p. 66-72
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: It is essential to fabricate a best-fit three-dimensional (3D) facial prosthesis model capable of facial expressions. In order for the facial prosthesis to remain in position, especially around marginal areas subject to movement, a new method of making 3D facial expression models using time-series data allowing changes in facial expression by morphing technique was developed.

    Methods: Seven normal subjects and seven patients with nasal defects or nasal deformities participated in this study. Three distinct facial expressions (i.e., a neutral expression, smiled, and open mouthed) were digitally acquired with a facial scanner. Prepared template models were transformed to homologous models, which can represent the form as shape data with the same number of point cloud data of the same topology referring to the scanning data. Finally, 3D facial expression models were completed by generating a morphing image based on two sets of homologous models, and the accuracy of the homologous models of all subjects was evaluated.

    Results: 3D facial expression models of both normal subjects and patients with nasal defects were successfully generated. No significant differences in shape between the scanned models and homologous models were shown.

    Conclusions: The high accuracy of this 3D facial expression model in both normal subjects and patients suggests its use for fabricating facial prostheses.

  • Moe Kosaka, Yuka I. Sumita, Hisashi Taniguchi, Toshihiko Suzuki, Keiic ...
    2019 年 63 巻 1 号 p. 73-77
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: The purpose of this study was to investigate the influence of dento-maxillary prosthesis adjustment procedure on levels of salivary cortisol.

    Methods: Nine participants (six men, three women, mean age 65.9 years) took part in this study. Saliva samples were collected before and after dento-maxillary prosthesis adjustment during the four different visits. Free cortisol levels were determined using a salivary cortisol immunoassay kit (expanded-range high-sensitivity salivary cortisol enzyme immunoassay kit, Salimetrics). Besides, original self-report sheets, a 35-item food intake questionnaire, the University of Washington Quality of Life (UW-QOL) questionnaire version 4, and the Geriatric Oral Health Assessment Index (GOHAI) questionnaire were also administered. The changes of salivary cortisol levels were analyzed using 2-level multilevel linear regression, with adjustment for age, sex, and time. Wilcoxon signed-rank test was used to compare scores of the food intake questionnaire, UW-QOL questionnaire, and GOHAI questionnaire.

    Results: Salivary cortisol levels decreased significantly after carrying out the dento-maxillary prosthesis adjustment procedure. During the third adjustment, the salivary cortisol levels were significantly low. In addition, salivary cortisol levels of participants aged 70 years and over were significantly higher than other aged groups. The total scores for grade III–V of the food intake questionnaire increased significantly. Other questionnaires had a trend toward increasing scores, yet the differences were not significant.

    Conclusions: Within the limitations of this study, the results suggest that a reduction in symptoms of discomfort may have an influence on the decrease of salivary cortisol levels in dento-maxillary prosthesis wearers.

  • Shoko Miura, Shin Kasahara, Shinobu Yamauchi, Yusuke Katsuda, Akio Har ...
    2019 年 63 巻 1 号 p. 78-84
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: To evaluate the early performance of computer-aided design/computer-aided manufacturing (CAD/CAM)-produced composite resin crown (CAD/CAM composite crown) treatment on premolars, specifically, placement on a removable partial denture (RPD) abutment tooth, and the distalmost tooth in the dental arch, as possible clinical risk factors.

    Methods: A retrospective cohort study (April 2014 to July 2017) was performed utilizing the clinical records of patients who received a premolar CAD/CAM composite crown treatment. The variables of time of treatment for (1) successful crowns (complication event-free) and (2) surviving crowns (clinically functional including re-luted) were estimated using Kaplan–Meier analysis. Survival distributions regarding "RPD abutment tooth" and "distalmost tooth" were analyzed with the log-rank test. Multilevel survival analyses were used to identify hazard ratios and associated risk factors.

    Results: Five hundred and forty-seven crowns were evaluated (mean follow-up time 1.3 ± 0.9 years) in 327 patients. A total of 87 crowns had at least one complication, with loss of crown retention being the most common (70 crowns). Estimated success and survival rates at 3 years were 71.7% and 96.4%, respectively. The risk of complications was significantly higher for an RPD abutment tooth than for a non- RPD abutment tooth. There was no significant difference between the distalmost tooth and nondistalmost tooth in the dental arch.

    Conclusions: The demonstrated complication rate for CAD/CAM composite crowns placed on premolars was 15.9% over a period of up to 3 years. There was a substantial risk of complications with placement of such a crown on an RPD abutment tooth.

  • Akinori Tasaka, Satoru Matsunaga, Kento Odaka, Ken Ishizaki, Takayuki ...
    2019 年 63 巻 1 号 p. 85-89
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: The aim of the present study was to compare the accuracy and retentive force of an experimental denture base fabricated using additive manufacturing and heat curing.

    Methods: A maxillary edentulous jaw model made of silicon was used. The shape data for the working cast and wax pattern of the experimental denture base were obtained using a dental laboratory scanner. Fabrication of the experimental denture bases was performed using heat curing and additive manufacturing. The shape data for the experimental denture bases was captured using an optical scanner. The shapes of the two experimental denture bases were compared with the shape of the working cast. A digital force gauge was used to measure the traction force. Pulling was maintained until the experimental denture base separated from the elastic model. Retention was set as the maximum value for the traction force. In order to compare the retentive force of the two experimental denture bases.

    Results: The experimental denture base fabricated using additive manufacturing was more accurate than the experimental denture base fabricated using heat curing. The experimental denture base fabricated using additive manufacturing demonstrated greater retentive force than the experimental denture base fabricated using heat curing.

    Conclusions: In this study, the experimental denture base fabricated using additive manufacturing was more accurate and obtained greater retentive force than the experimental denture base fabricated using heat curing.

  • Chunwoo Lee, Satoshi Yamaguchi, Keisuke Ohta, Satoshi Imazato
    2019 年 63 巻 1 号 p. 90-94
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: The aim of this study was to determine the mechanical properties of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composites for dental restoration assuming perfect silane coupling by in silico homogenization analysis using a three-dimensional model constructed from cryo-electron microscopy (cryo-EM) images.

    Methods: Three-dimensional dataset of a commercial CAD/CAM resin composite block (RCB) was obtained using EM with cryo-stage and focused ion beam at -130 °C. The region of inspection was 1.8 μm × 1.4 μm × 1.2 μm, and 213 slices were obtained from this region. Each slice was processed (noise reduction, threshold setting, and segmentation) using image processing software to design an in silico model. From the processed image slices, a bulk three-dimensional object and stereolithography model were reconstructed using voxel modeling software. To evaluate the elastic modulus and Poisson's ratio of the CAD/CAM RCB, homogenization analysis was performed.

    Results: The generated voxel model included 37,276,216 voxels, 42,472,040 patches of the surface, 2,123,672 nodes, a volume of 165,748,899, and a surface area of 175,206,723. The mean of the elastic moduli along each axis was 10.71 ± 1.79 GPa. The mean of the Poisson's ratios of each plane was 0.23 ± 0.02.

    Conclusions: A CAD/CAM resin composite model was successfully reconstructed from cryo-EM images, suggesting that the established image processing method is useful for producing dental restorative materials containing nano-fillers and for predicting homogenized mechanical properties. The homogenized mechanical properties indicated that the mechanical properties of the CAD/CAM RCB assumed perfect silane coupling between the fillers and resin matrix.

  • Haruto Hiraba, Hiroshi Nogawa, Hiroyasu Koizumi, Akihisa Kodaira, Shun ...
    2019 年 63 巻 1 号 p. 95-99
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: This study investigated the influence of an interaction between sulfur-containing monomers and other monomers in multipurpose primers on the bond durability of a tri-n-butylborane (TBB)-initiated acrylic resin to a gold alloy.

    Methods: The disk-shaped adherend materials were prepared from a gold alloy (Casting Gold M.C. Type IV). Two multipurpose-primers (Universal Primer, Monobond Plus), four metal primers containing an organic sulfur compound (M.L. Primer, Alloy Primer, Metaltite, and V-Primer), and three acidic primers (Estenia Opaque Primer, Acryl Bond, and Super-Bond Liquid) were used. The shear bond strengths were determined pre- and post-thermocycling to evaluate the bond durability. A statistical analysis of the results was performed using a non-parametric procedure, and the cohesive failure ratios of the debonded surfaces were compared.

    Results: Among the pre-thermocycling groups, M.L. Primer, Metaltite, Monobond Plus, Universal Primer, and Alloy Primer showed the greatest bond strengths. Among the post-thermocycling groups, M.L. Primer, Metaltite, Monobond Plus, and Universal Primer showed the greatest bond strengths, whereas Acryl Bond, Super-Bond Liquid, Estenia Opaque Primer, and the unprimed control showed the lowest. Similarly, the primers that did not contain either a sulfur compound showed an obvious reduction in the cohesive failure ratio.

    Conclusions: Multi-purpose primers containing a sulfur-containing monomer increased the bond strength of a TBB-initiated acrylic resin to a gold alloy. The proportion of the area of cohesive failure to the bonded area showed an interrelationship with the shear bond strength testing results.

  • A. Arena, P. Baldissara, L. Ciocca, R. Scotti, C. Monaco
    2019 年 63 巻 1 号 p. 100-104
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: To evaluate the influence of the preparation design and spacing parameters on the risk of chipping of crowns made by CEREC Bluecam before cementation.

    Methods: A knife-edge preparation and a chamfer preparation were made on upper premolars. The teeth were scanned and two Co–Cr alloy replicas were made. Fifteen full crowns were manufactured for four groups using CEREC. The groups differed in type of preparation (knife-edge (KE) or chamfer (CHA) ) and spacing parameters: spacer (0 or 150 μm), marginal adhesive gap (10 or 50 or 150 μm) and margin thickness (0 or 300 μm). The four groups were: CHA 150 (spacer)- 50 (marginal adhesive gap)- 0 (margin thickness), KE 150-50-0, KE 150-50-300 and KE 150-150-300. The crowns were loaded before cementation by using an Instron machine to simulate the masticatory load applied during a trial. Differences in means were compared using two-way ANOVA and a post-hoc test (Tukey Test). The level of significance was set at P = 0.05.

    Results: The fracture values, ordered from least to most resistant, were: KE 150-50-300 group, CHA 150- 50-0 group, KE 150-50-0 group and KE 150-150-300 group. Two-way ANOVA revealed statistically significant differences between pairs of means (p < 0.05). Tukey's test showed that restorations of the KE 150-150-300 group can withstand a load significantly higher than that of other groups (p < 0.01). In this group, the failures were mostly minor chippings, while the other groups had mostly major chippings and fractures.

    Conclusions: Marginal adhesive gap can affect the trial of a full crown.

  • Motoyoshi Fukutake, Kazunori Ikebe, Hitomi Okubo, Ken-ichi Matsuda, Ka ...
    2019 年 63 巻 1 号 p. 105-109
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: Oral stereognostic ability (OSA) is a useful indicator of oral perception to recognize food characteristics during mastication. Previous studies have shown associations between dietary intake and oral health status, such as taste perception. However, the effect of oral sensory ability on dietary intake is unclear. The purpose of this study was to investigate the association between oral sensory ability and dietary intake in older Japanese complete denture wearers.

    Methods: This cross-sectional study included 164 participants aged 69–71 or 79–81 years old, wearing both maxillary and mandibular complete dentures. OSA test was used to evaluate oral tactile perception. Diet during the preceding month was assessed using a self-administered diet history questionnaire. Multivariable linear regression analysis was conducted to assess the association between OSA score and food and nutrient intake after adjusting for age, sex, socioeconomic factors, and occlusal force.

    Results: The bivariate analysis showed that OSA score was significantly and positively correlated with intake of green and yellow vegetables and negatively correlated with intake of cereals among examined foods. OSA score was also positively correlated with intake of vitamins A, B2, and C and α-tocopherol (as a substitute for vitamin E) among examined nutrients. After adjusting for age, sex, socioeconomic factors, and occlusal force, OSA score remained significantly associated with intake of green and yellow vegetables and α-tocopherol.

    Conclusions: OSAwas significantly associated with intake of green and yellow vegetables in older complete denture wearers.

  • Almina Muric, Bilge Gokcen Röhlig, Deger Ongul, Gulumser Evlioglu
    2019 年 63 巻 1 号 p. 110-114
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: Reconstruction of patients' dental occlusion should be performed to fulfill esthetic and functional demands. These applied restorations should be in harmony with the existing occlusion and should not have any negative effects on intraoral dynamics. The aim of this clinical study is to compare the accuracy of the occlusal design shaped by conventional Wax Up methods and computer-aided design (CAD) regarding their similarity to the natural tooth morphology.

    Methods: Impressions of 10 caries-free jaws were taken, and the resulting gypsum casts were scanned with a laboratory scanner. Preparations for all-ceramic full crowns were performed on second premolars and second molars. Occlusal design of 40, 3-member fixed partial dentures (FPD) were obtained with two different methods 10 FPD was designed with conventional wax up technique (Wax Up), 30 design was performed with CAD Dental wings open system (DWOS) software using three different anatomy libraries (Dental Wings (DW), Merz, Vita). The data of the bridges in the STereo-Lithography Interface Format (STL) was compared with the pre-cut data, which was regarded as a reference in terms of accuracy in the Atos so high end 3D digitizer.

    Results: According to the results of Kruskal–Wallis test, there was no statistical difference between the Wax Up, Vita, Merz and Dental Wings groups (p > 0.05) when compared to the natural teeth. The main difference between all four groups and natural surface was 550 ± 130 μm.

    Conclusions: Occlusal design produced by conventional techniques and CAM DWOS system compared to natural tooth morphology showed no statistically significant difference.

Technical Procedure
  • Joo Hyun Kwon, Sungbin Im, Minho Chang, Jong-Eun Kim, June-Sung Shim
    2019 年 63 巻 1 号 p. 115-119
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: This technical procedure describes a method for tracking mandibular movement using a threedimensional (3D) optical scanner and target tracking system to digitally portray the motion of the mandible and temporomandibular joints by merging cone beam computed tomography (CBCT) data.

    Methods: Four nonreflective targets were attached to the labial surface of the incisors in a noncolinear arrangement. Mandibular movement was tracked directly using a 3D facial scanner and target tracking software after merging facial scanning data, digital data obtained from a diagnostic cast, and CBCT scan data based on several landmarks of the anterior teeth. The moving path of the subjects' mandible was converted to CBCT-based data to confirm the actual movement of the mandible and temporomandibular joints.

    Conclusions: The digital implementation of mandibular movement using a 3D optical scanner and target tracking system is not prone to the same restrictions and limitations inherent in mechanical equipment; therefore, it is possible to reconstruct more realistic movement (s). This technique can be used in a wide variety of dental applications involving movement of the mandibular jaw, such as fabrication of dental prostheses, or for the diagnosis and treatment of temporomandibular joint disease.

  • Jong-Eun Kim, Ji-Hyun Park, Hong-Seok Moon, June-Sung Shim
    2019 年 63 巻 1 号 p. 120-124
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: To introduce a new and simple digital workflow to record dynamic occlusion, and apply it to occlusal analysis and prosthetic treatment in a virtual environment.

    Methods: A table-top scanner (Identica hybrid) was used to transfer fabricated casts into a virtual environment. A facial scanner (Rexcan CS2) was used for facial scanning and target tracking. Four targets were attached to each of the four incisors in the maxilla and mandible to track jaw movement. Target position data were recorded in real time during eccentric movement. The targets were replaced with maxilla and mandible cast scan data, and mandibular movement relative to the maxilla was reconstructed. Four types of antagonist meshes were reconstructed in computer-aided design (CAD) software (EzScan8). The CAD software (Exocad) enabled checking of occlusal contacts in the maximal intercuspation position during eccentric movement.

    Conclusions: Target tracking data were transformed into video clips of dental cast scan data, which showed jaw movements in real time. Occlusal contact information was produced by the CAD software. Both dynamic and static occlusion analyses were performed with reconstructed eccentric movement antagonist meshes. Our new method for reconstructing eccentric movements of the mandible can reveal the occlusal dynamics of a patient within a virtual environment.

  • Yoko Kurosaki, Takuya Mino, Kenji Maekawa, Koji Izumi, Takuo Kuboki
    2019 年 63 巻 1 号 p. 125-129
    発行日: 2019年
    公開日: 2019/02/25
    ジャーナル 認証あり

    Purpose: This report was written to introduce an attempt at clinical application of our newly developed digital workflow to reproduce the morphology of the subgingival contour and the emergence profile of the provisional restoration within the final bone-anchored fixed restoration, using a bounded unilateral edentulous case.

    Methods: This digital workflow involves superimposition of the composite images of two specific types of working casts onto the working cast for the provisional restoration namely, a split cast screwed with a titanium base and a split cast screwed with a provisional restoration and integrating these with the whole intraoral surface image, in which the provisional restoration was present. The final restoration fabricated using this technique could be installed without any clinical problems. The results of in silico analysis revealed that the cubic volume ratio of the total discrepancy between the provisional and the final restorations was only 2.4%. Further, sufficient oral hygiene was maintained and the patient was satisfied with the outcome of the treatment.

    Conclusions: This technical report suggests that our newly developed digital workflow provided clinical applicability and may enable accurate transfer of the morphology of the subgingival contour and emergence profile of the provisional to the final bone-anchored fixed restoration.

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