Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry最新文献

Purpose: To evaluate the impact of palatal alveolar bone thickness at the implant platform level on bone resorption and failure rates in the maxillary aesthetic zone.

Materials and methods: From 2018 to 2023, 81 patients with 118 implants were included. This retrospective study used cone-beam computed tomography to measure labial/palatal bone thickness at three stages (T0: postoperative; T1: 3 months; T2: 6 months). The data are presented as the means ± SDs, with significance set at p < 0.05. Relationships between palatal alveolar bone thickness and implant outcomes were evaluated using Pearson correlations, Chi-square tests, and ANOVA with eta-squared statistics. ROC curve analysis was used to determine the cutoff value for failure-related bone thickness.

Results: The palatal alveolar bone at the level of the implant platform was unrelated to the bone resorption or failure rate. ROC analysis (AUC = 0.651) identified < 5.76 mm palatal bone thickness at T0 (root tip level) as a significant failure risk predictor (p < 0.05). Horizontal palatal and labial bone thickness decreased by 21.79% ± 41.18% (p < 0.05) from T0 to T2, with greater labial bone loss.

Conclusions: Palatal alveolar bone thickness at the implant platform level does not influence bone resorption outcomes or survival rates in the maxillary aesthetic zone. However, excessive reduction of palatal bone at the root tip (< 5.76 mm) increases failure risk. Preoperative planning should preserve adequate palatal bone mass while avoiding unnecessary bone removal for long-term stability.

Purpose: Evidence-based dentistry relies on valid statistics, yet misuse remains common. Despite increased emphasis on statistical rigor, recent prosthodontic publications remain underexplored. We hypothesized that statistical misapplications and reporting deficiencies persist in prosthodontic research. This study evaluated the appropriateness, application, and reporting of statistical tests in high-impact prosthodontic journals.

Methods: Original clinical studies published between January 2019 and December 2024 in the Journal of Prosthodontics (JOP), International Journal of Prosthodontics (IJOP), and Journal of Prosthetic Dentistry (JPD) were screened. Eligible articles used quantitative methods with inferential statistics. A 20% stratified random sample ensured representation by journal and year. Articles were assessed using a specialty-adapted checklist covering five domains: test selection, sample size justification, assumption testing, examiner calibration, and result interpretation. A weighted scoring system categorized studies as having no major, minor, or major error. Descriptive statistics and Pearson's Chi-square test, with Monte Carlo simulation as needed, assessed associations. Twenty percent of articles (n = 24) were double-scored; consensus yielded inter-rater reliability κ = 0.94.

Results: A total of 119 clinical studies were reviewed (JPD 57, IJOP 37, JOP 25). Appropriate statistical tests were used in 88% of studies; notably, all 19 studies that involved a statistician demonstrated correct test selection. However, only 32% reported sample-size calculations. Assumption testing was completed in 47% of studies, and examiner calibration was described in 40%. Confidence intervals were absent in 83% of reports, with only 8% both reporting and interpreting them. Overall, 45% of studies had no major statistical error, 35% contained major errors, and 21% showed minor deficiencies. Having no major error was strongly associated with proper test selection and assumption verification (p < 0.001).

Conclusions: Statistical reporting deficiencies persist in prosthodontic research, particularly in sample-size justification, assumption testing, and confidence interval reporting, highlighting the need for specialty-specific checklists, enhanced training, and stronger editorial/reviewer standards.

Purpose: To evaluate the effect of different self-etching primer (Monobond Etch & Prime-MEP) application protocols and aging on micro shear bond strength (µSBS) and surface etching patterns of zirconia-reinforced lithium silicate (ZLS) and lithium disilicate (LD) ceramics.

Materials and methods: Twenty-eight blocks of Vita Suprinity (VS), Celtra Duo (CD), and IPS e.max CAD (EM) were cut into two sections each (n = 56 specimens per ceramic) and divided into groups: 5% hydrofluoric acid with silane (HF + S, control), and MEP scrubbing for 20, 40, and 60 s, with a 40-s reaction time (n = 14 per condition; n = 10 for µSBS and n = 4 for scanning electron microscopy [SEM]). For µSBS, resin cement was applied and light-cured; half of the resin cylinders were stored for 24 h, while the other half underwent thermocycling (TC) (10,000 cycles; dwell time of 30 s between 5°C and 55°C) before testing. Data were analyzed using three-way repeated measures analysis of variance (ANOVA) and Bonferroni post hoc tests (α = 0.05).

Results: The HF + S group showed higher µSBS for EM than VS and CD (p < 0.001). MEP100 achieved comparable µSBS with HF + S for CD (p < 0.001) and improved µSBS for VS and EM (p = 0.128). TC decreased the µSBS values in most groups. The only exception was observed when the VS and CD surfaces were treated with MEP100, and when the CD surface was treated with MEP80. Adhesive fractures were predominantly seen. SEM revealed MEP100 produced etching patterns like HF, with lithium metasilicate and orthophosphate crystals present.

Conclusions: Prolonged MEP application (MEP100) produced etching patterns and µSBS values comparable to HF + S, making it a viable surface treatment alternative for ZLS and LD ceramics.

Purpose: This study examined the survival rate of implants and maxillary implant-supported overdentures (MIS-ODs) and identified the frequency of maintenance needs as well as technical and biological complications associated with MIS-ODs.

Materials and methods: This retrospective cohort study included 86 patients who received 86 MIS-ODs between 1982 and 2023 in a university setting. Data analyses were performed to determine the survival rate of implants and MIS-ODs, as well as the frequency of maintenance events and complications (technical and biological). The survival proportion of MIS-ODs was estimated, and prognostic factors were analyzed using Cox regression analyses (p < 0.05).

Results: The median follow-up time for MIS-ODs in this study was 39.0 months (interquartile range [IQR]: 15.0-84.3). Among 86 MIS-ODs, 45.3% had non-splinted attachments and 54.7% had splinted attachments; 9.3% of prostheses were supported by 2 to 3 implants, 59.3% by 4 implants, and 31.4% by more than 4 implants. The most common maintenance intervention was adjustment of the prosthesis intaglio surface. Technical complications occurred in nearly 60% of cases, with inadequate prosthesis retention being the most frequently reported issue. The most prevalent biological complication was peri-implant mucositis. Lastly, 27.9% of prostheses (24 cases) required a new prosthesis after a median survival time of 58.5 months (IQR: 16.0-79.0) due to acrylic tooth wear, implant loss, fabrication errors, and suboptimal retention.

Conclusions: Within the limitations of this study, MIS-OD survival is independent of the prosthesis design characteristics. However, certain technical and biological complications can affect the survival of MIS-ODs.

Purpose: To compare the stainability, translucency, opalescence, whiteness, gloss, and hardness of 4 computer-aided design and computer-aided manufacturing (CAD-CAM) restorative materials after simulated coffee drinking and color correction.

Materials and methods: Four CAD-CAM blocks were investigated (n = 40): resin nanoceramic (Cerasmart, CS), polymer-infiltrated ceramic network (Vita Enamic, VE), lithium disilicate glass ceramic (IPS e.max CAD, EC), and zirconia-reinforced lithium silicate glass ceramic (Vita Suprinity, VS). The color stability (ΔE₀₀), relative translucency (RTP), opalescence (OP), and whiteness stability (ΔWI_D) were measured with a spectrophotometer. Gloss (GU) was recorded with a gloss meter, and hardness (HM) was detected with a Martens hardness testing device. The specimens were observed at baseline (T0), after coffee thermocycling (CTC) (T1), and after color correction (T2). ΔE₀₀ was analyzed by two-way ANOVA, ΔWI_D was analyzed with one-way ANOVA, and RTP, OP, WI_D, GU, and HM were assessed with repeated ANOVA to evaluate the effects of material type, treatment, and their interactions on the tested properties. Post hoc pairwise comparisons were assessed by Tukey HSD and Student t-tests (α = 0.05).

Results: ΔE₀₀, WI_D, OP, GU, and HM outcomes were significantly impacted by material type (p < 0.001) and treatment (p ≤ 0.028), whereas ΔWI_D and RTP were affected by material type (p ≤ 0.03). CS exceeded the ΔE₀₀ perceptibility threshold at T1. VS exhibited the highest stain resistance, RTP, and HM, and the least was in VE and CS. Color correction serums reversed CTC-induced staining among VS and VE (p < 0.001).

Conclusions: Zirconia-reinforced lithium silicate glass-ceramics demonstrated superior color stability and hardness when subjected to coffee thermocycling and color correction serum.

Purpose: This study evaluates the thermodynamic benefits of including an irrigation fluid channel in the design of surgical guides used for dental implant site drilling.

Materials and methods: Two types of guides suitable for hosting artificial bone plates that mimic the mechanical properties of human alveolar bone were designed: a classical guide (CLA-a splint with a guiding cylinder) and a guide with an internal coolant channel (INT). They were fabricated from titanium powder by selective laser melting. Graduated drillings were performed using a pilot bur followed by two larger ones; infrared thermography was used to record the temperature of the drill upon exit and the peak temperature of the specimen right after the bur's retraction.

Results: The rise in bone temperature (mean ± standard deviation) while drilling through the CLA (INT) guide was 13.2 ± 3.6 (9.0 ± 3.4)°C for Drill 1, 4.3 ± 1.0 (2.1 ± 1.0)°C for Drill 2, and 2.1 ± 0.6 (0.4 ± 0.5)°C for Drill 3; the differences were statistically significant (p < 0.0032). To characterize individual differences between pairs of drillings conducted with different guides, Bland-Altman analysis was performed for the most thermogenic step. The mean difference between temperature elevations recorded with CLA and INT was -5.8°C, whereas the limits of agreement were 2.9°C and -14.4°C. In 95% of the cases, INT displayed more efficient cooling than CLA.

Conclusion: Surgical guides with incorporated coolant channels ensure better heat removal than conventional guides. Further research is needed to assess bone overheating within a few hundred micrometers from the osteotomy edge.

Purpose: The purpose of this study is to analyze the impact of changes in the implant-abutment interface fit taper on loosening and fatigue performance.

Materials and methods: Three abutment structures with varying tapers (11.5°, 12°, and 13°) were self-designed and customized. Then, the impact of different taper fits between the abutment and implant on loosening and fatigue performance was investigated. The experiments measured screw preload, static and dynamic loosening torque, abutment settlement, pullout force, and the fatigue life of the implant system. The surface wear of the abutment and fatigue fracture surfaces were analyzed, and the experimental results were validated through finite element analysis (FEA).

Results: The abutment and implant have the same 11.5° matching taper increased preload, loosening torque, pullout force, and fatigue life. The fracture of the implant system occurs at the simulated bone plane, and the FEA of the stress concentration area aligns with the fatigue fracture results.

Conclusions: Adopting a consistent 11.5° taper design at the abutment-implant interface could enhance the anti-loosening effect and extend the fatigue life, but a higher abutment pullout force may increase the difficulty of clinical restoration. Therefore, when the connection cone angle of the implant is 11.5°, using a 12° conical abutment may achieve optimal application results.

Purpose: Performing endodontic procedures on existing crowns is common when replacing the crown is not feasible. Traditional triangular access (TTA) is standard for maxillary molars, but more conservative designs are reported in the literature. However, research comparing the fracture resistance of maxillary molar zirconia crowns using traditional and novel endodontic access sealed with composite resin remains limited. The purpose of this in vitro study was to evaluate the fracture resistance of maxillary molar zirconia crowns with various endodontic cavity designs: traditional triangular access (TTA), conservative triangular access (CTA), and conservative circular access (CCA). A control group with no endodontic access (NEA) was also included.

Materials and methods: A maxillary right first molar typodont tooth was prepared for a full all-ceramic crown. The preparation was scanned, and 48 dies were 3D-printed based on the tooth preparation. A total of 48 zirconia crowns were fabricated (n = 12 per group) and divided into four groups according to the endodontic access cavity design: TTA, CTA, CCA, and a control group without an endodontic cavity. To ensure consistency, all restorations were designed and fabricated using a digital workflow. Endodontic access was created using a specialized bur kit and sealed using a repair kit for damaged ceramic restorations along with resin composite. The restorations were cemented, and all samples underwent artificial aging with 10,000 thermal cycles between 5°C and 55°C, with a dwell time of 30 s. The samples were then loaded to failure using a universal testing machine. The maximum load to fracture was analyzed using a one-way ANOVA and post hoc Tukey honestly significant difference (HSD) test (α = 0.001). Additionally, the fracture patterns of the specimens were evaluated descriptively using a scanning electron microscope.

Results: The mean fracture resistance of maxillary molar zirconia crowns varied significantly by endodontic access type. CCA showed the highest resistance (3677 N) among access groups, followed by CTA (3385 N) and TTA (2927 N). The control group NEA (3834 N) exhibited the highest overall resistance, exceeding all access groups.

Conclusions: Conservative access designs increased the fracture resistance of zirconia crowns compared with traditional access, with circular access showing the highest strength. However, all access preparations reduced resistance relative to crowns without endodontic access.