Purpose: This systematic review set out to investigate the influence of chemical composition and specimen thickness of monolithic zirconia on its optical and mechanical properties. Meta-analysis and meta-regression analyzed the effects of variations in percentages of yttrium, aluminum, and specimen thickness of monolithic zirconia.

Study selection: The review followed recommendations put forward in the PRISMA checklist. An electronic search for relevant articles published up to October 2019 was conducted in the Pubmed, Cochrane, Scopus, Scielo, and Web of Science databases, with no language limits and articles published in the last 10 years. From 167 relevant articles; applying inclusion criteria based on the review’s PICO question, 26 articles were selected for qualitative synthesis (systematic review) and 24 for quantitative synthesis (meta-analysis). Experimental in vitro studies published were selected and their quality was assessed using the modified Consort scale for in vitro studies of dental materials.

Results: The variables yttrium, aluminum and thickness were analyzed in random effects models, observing high heterogeneity (>75%), and finding statistically significant influences on the properties of monolithic zirconia (p<0.05).

Conclusion: Within the review’s limitations, it may be concluded that variations in the percentage of yttrium and aluminum influence the optical and mechanical properties of monolithic zirconia, making it more or less esthetic and resistant in relation to each variable. The clinical implications of these findings can help select the most appropriate type of zirconia to meet the different clinical needs when restoring different regions (posterior or anterior).

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).

Conclusion: 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.

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 can be easily fabricated by locating the neutral zone using denture space recording methods.

Conclusion: 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.

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.

Conclusion: 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.

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.

Conclusion: 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.

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 measurement 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.

Conclusion: The final color of the monolithic zirconia crowns was significantly influenced by the tooth portion evaluated and the color of the abutment tooth.

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.

Conclusion: 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.

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 monolithic 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.

Conclusion: 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.

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).

Conclusion: An adequate initial retentive force can be achieved with telescopic crowns combining zirconia and FRC.

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.

Conclusion: 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.

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.

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

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.

Conclusion: The application of bonding resin after alcohol cleaning is the most convenient and effective clinical procedure for fiber post surface treatment.

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.

Conclusion: 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.

Purpose: To measure the durability of the color, change in surface roughness and gloss of stained monolithic ceramic materials subjected to artificial tooth brush abrasion.

Materials and methods: Standardized specimens were manufactured from pressable lithium-disilicate glass ceramic (PC; IPS e.max Press), machinable lithium-disilicate glass ceramic (MC; IPS e.max CAD), and zirconia (ZR; Zenostar). Ceramic staining was applied before (internal; in) and after crystallization/sintering (external; ex). Of each ceramic material, specimens without staining were prepared (no staining; no). Porcelain-fused-to-metal specimens served as control (PFM). Each group consisted of 15 specimens. Tooth brushing was simulated with tooth brushing strokes of 21.6 k, 43.2 k, and 64.8 k. Color, gloss and roughness were measured at baseline and after cycle intervals. Kruskal-Wallis and paired Post-hoc Conover tests were applied to detect statistical differences between treatment groups. Differences before and after aging were calculated by Wilcoxon signed rank test (α=0.05).

Results: In all groups, color difference (∆E) was statistically significant after aging: no-PC (P<.001, 95% CI[0.14,0.84]), no-MC (P=.003, 95% CI[0.23,1.12]), no-ZR (P=.003, 95% CI[0.33,0.62]), in-MC (P=.003, 95% CI[0.35,0.73]), in-ZR (P=.003, 95% CI[0.09,0.32]), ex-PC (P=.003, 95% CI[0.54,0.98]), ex-MC (P<.001, 95% CI[0.23,1.26]), ex-ZR (P=.003, 95% CI[0.27,0.55]), and PFM (P=.002, 95% CI[0.22,0.34]). Aging increased surface roughness and decreased the gloss within all subgroups showing statistical significance.

Conclusion: Color, gloss and roughness of stained monolithic ceramic materials changed significantly by means of tooth brush abrasion in vitro. Color changes were below the threshold value for the detection by the human eye (∆E 1.8).

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 lacunar infarcts.

Conclusion: 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.

Purpose: The accuracy of intraoral and model scanners has been widely investigated with heterogeneous results, but the impact of the applied diversity of measurement methods on the outcomes remains unknown. This study aimed to evaluate the influence of methodological factors on the measurement result when comparing full-arch scans.

Methods: The evaluation referred to a 5M model to analyze whether accuracy measurements are affected by (1) the reference geometry, (2) mesh density of the standard tessellation language (STL) datasets, (3) operator, (4) inspection software, and (5) alignment procedure. STL datasets of full-arch reference models were measured with 29 different combinations of these factors. For each combination, 10 repeated measurements of the intermolar width were performed. Trueness was statistically analyzed with one-way ANOVA and T-tests, repeatability with Levene tests, and reproducibility with interclass correlation coefficients.

Results: Measurement method variations affected the intermolar width by up to 186 µm. The alignment algorithm had a significant effect on the measurement outcome (p = 0.001). Likewise, reference geometry influenced trueness and repeatability significantly (p = 0.001), whereas mesh density affected the repeatability only in some cases. The operator had no impact on the measurement result. The inspection software affected the repeatability but not the trueness.

Conclusion: The factors reference geometry and alignment algorithm highly affected the measurement outcome, while the operator, inspection software, and mesh density showed no impact on the trueness of the outcome. Cylindrical reference geometries showed fewer differences than bar-shaped ones and best-fit alignments fewer variations than alignments based on boundary parameters.

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.

Conclusion: 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.

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 variance 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.

Conclusion: 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 maxillary anterior cantilever zirconia RBFDPs.

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.

Conclusion: Monolithic and partially veneered zirconia crowns can be used clinically with high medium-term survival and success and uncompromised esthetic results.

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.

Conclusion: 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.

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.

Conclusion: 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.