Journal of Prosthetic Dentistry最新文献

Statement of problem: Studies on the assessment of the marginal fit of interim crowns with optical coherence tomography (OCT) are lacking.

Purpose: The purpose of this in vitro study was to apply OCT to evaluate and to compare the impact of conventional and computer-aided design and computer-aided manufacturing (CAD-CAM) fabrication methods and different materials, including bis-acryl, conventional polymethyl-methacrylate (PMMA), and CAD-CAM PMMA, on the marginal fit of interim crowns.

Material and methods: Thirty crown specimens were fabricated, with 20 PMMA crowns divided into 2 groups based on the fabrication method: the conventional method (Group Jet, n=10) and the CAD-CAM method (Group CAD-CAM PMMA, n=10). An additional 10 bis-acryl crowns were fabricated using the conventional method (Group Protemp, n=10). The marginal gap was assessed at 8 specific points using swept-source OCT. Comparisons between the fabrication methods of PMMA crowns and different materials of conventionally made crown were done using an independent t test (α=.05).

Results: Group CAD-CAM PMMA recorded statistically significant lower total mean vertical marginal gap values (22.2 ±4.7 µm) compared with group Jet (62.6 ±2.2 µm) (P<.001). Among the conventional interim material, Group Protemp showed significantly lower values (57.6 ±5.2 µm) compared with group Jet (62.6 ±2.2 µm) (P=.02).

Conclusions: The CAD-CAM fabrication method presented smaller marginal gaps. Among the conventional interim crown materials, bis-acryl showed smaller marginal gaps than PMMA.

Statement of problem: Attempting to combine the mechanical and optical properties of ceramics and composite resins to mimic natural teeth has led to the emergence of resin nanoceramics and polymer interpenetrating ceramic network materials. Systematic reviews on the survival of these materials in endodontically treated teeth are lacking.

Purpose: This systematic review and meta-analysis assesses the survival of computer-aided design and computer-aided manufacturing (CAD-CAM) resin nanoceramics and polymer interpenetrating ceramic network material restorations on endodontically treated teeth and to describe the incidence of complications.

Material and methods: The study was registered in the international prospective register of systematic reviews (PROSPERO) database and adhered to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. A comprehensive search across 6 online databases was performed. Clinical studies which involved CAD-CAM manufactured resin nanoceramics and polymer interpenetrating ceramic network material restorations on endodontically treated teeth were included. Several investigators independently conducted the study selection, data extraction, and quality assessment processes. Risk of bias was assessed by using the Cochrane Risk of Bias 2 tool and Newcastle-Ottawa Scale. Failure rates were analyzed using Poisson regression models to obtain summary estimates of 3- and 5-year survival proportions, which were pooled using a random-effects model. Subgroup analysis was performed for material type and restoration design (α=.05).

Results: The search resulted in 250 studies after duplicate removal, and 11 articles were included in the final analysis. The meta-analysis of 289 restorations revealed an overall estimated failure rate of 3.44 (95% confidence interval [95% CI]: 2.67-4.21) per 100 restoration years, equivalent to a survival rate of 90.2% (95% CI: 88.1-92.3%) after 3 years and 84.2% (95% CI: 81.0-87.5%) after 5 years. A significantly lower (P<.001) failure rate was reported for polymer interpenetrating ceramic network material restorations (1.61, CI: 0.87-2.36) compared with resin nanoceramic restorations (5.97, CI: 3.52-8.41). Partial-coverage restorations (3.45, 95% CI: 1.98-4.92) had a significantly lower (P<.001) failure rate compared with 1-piece endodontic crowns (5.19, 95% CI: 2.75-7.64). Restoration debonding was the main reason for failure.

Conclusions: Endodontically treated teeth restored with CAD-CAM manufactured resin nanoceramic and polymer interpenetrating ceramic network material restorations have an acceptable survival rate and can be recommended as an alternative to conventional indirect restorative materials. Polymer interpenetrating ceramic network material restorations have a higher survival rate than resin nanoceramic restorations.

Statement of problem: The hydraulic calcium silicate-based sealers (HCSSs) used in endodontic treatments have been reported to interfere with the bond of the post to root canal dentin. Post space irrigation plays a significant role in optimizing the bond, but which protocol is effective for cleaning HCSS-smeared intraradicular dentin is unclear.

Purpose: The purpose of this in vitro study was to evaluate the effect of passive ultrasonic irrigation (PUI) as an adjunct to different irrigation protocols, including with ethylenediaminetetraacetic acid (EDTA), chlorhexidine (CHX), and sodium hypochlorite (NaOCl), and root regions on the push-out bond strength of a self-etch primer-assisted resin luting agent adhered a post to root canal obturated with hydraulic calcium silicate sealer.

Material and methods: The palatal root of 60 human maxillary premolars were shaped and obturated with gutta-percha and HCSS (iRoot SP). The post space was prepared using a peeso reamer and double taper drill, and the specimens were divided into 6 groups (n=10) according to the following irrigation protocols: distilled water with conventional syringe, distilled water with PUI, 17% EDTA with PUI, 2% CHX with PUI, 17% EDTA + 2.5% NaOCl with PUI, and 17% EDTA + 2% CHX with PUI. Fiber-reinforced posts (DT Light-Post) were cemented with dual-polymerizing resin luting agent with self-etching primer (Panavia V5). Specimens underwent 6000 thermocycles, were sectioned into 3 slices, and were tested for push-out bond strength and failure mode. The 2-way mixed ANOVA, Kruskal-Wallis H, Dunn post hoc, and chi-squared tests were used for statistical analysis (α=.05).

Results: The PUI/EDTA/NaOCl group exhibited significantly higher push-out bond strength than irrigation with distilled water, whether incorporated with PUI or not (P=.001 and P=.007, respectively). The root region showed no statistical effects on bond strength (P>.05). The irrigation protocol was significantly associated with failure mode (P=.049).

Conclusions: PUI with EDTA/NaOCl followed by distilled water improved the bond strength of self-etch primer-assisted resin luting agent and fiber-reinforced post to an HCSS-obturated tooth. Alternative irrigation protocols did not significantly enhance bond strength.

Statement of problem: Research on antibacterial dental adhesives has increased over the last few years. However, whether antibacterial agents improve the efficacy of dentin bonding has not yet been determined.

Purpose: The purpose of this systematic review and meta-analysis was to evaluate whether antibacterial agents improve the efficacy of dentin bonding at the resin-dentin interface and to identify possible mechanisms.

Material and methods: Studies published within the last 10 years up to April 2024 were searched in 5 databases: PubMed (MedLine), EMBASE, Scopus, Web of Science, and Cochrane Library. A random-effects meta-analysis model was used, and pooled effect estimates were obtained by comparing the standardized mean difference (α=.05).

Results: A total of 61 studies with 9 different types of antibacterial agent were included in the qualitative and quantitative analyses. The meta-analysis indicated that treatment with metal-based inorganic antibacterial agents improved both the immediate and long-term bond strength values (P<.05). Moreover, incorporating carbon-based substances, quaternary ammonium compounds, chlorhexidine, methacrylate derivatives, and antibiotics enhanced the long-term bond strength of the resin composites to dentin (P<.05). Subgroup analysis indicated that including metal-based inorganic antibacterial agents, quaternary ammonium compounds, and methacrylate derivatives in etch-and-rinse (ER) adhesives improved dentin bond strength (P<.05), whereas carbon-based materials in self-etching (SE) adhesives showed better bonding performance.

Conclusions: The introduction of some antibacterial agents into the bonding system improved in vitro bond strength and inhibited bacterial growth. However, clinical trials should be conducted to verify in vivo antibacterial effects and bond strength.

Statement of problem: The rapid and safe removal of resin cement from tooth surfaces is challenging. Whether removal with a picosecond laser might providing a practical solution is unclear.

Purpose: The purpose of this in vitro study was to explore the effect and mechanism of a picosecond laser acting on resin cement and whether the dental tissue is damaged.

Material and methods: A 50-μm-thick layer of resin cement was prepared on the enamel surface of extracted teeth. The specimens were scanned with a picosecond laser with different laser power. Pulp temperature was monitored during laser processing, and the surface and section morphology was observed with a 3-dimensional (3D) digital microscopy system and a scanning electron microscope. The ablation depth in the enamel was measured and calculated. Data were statistically analyzed with one-way analysis of variance (ANOVA). A Raman spectrometer was used to analyze component change in the resin cement.

Results: The surface morphology of cement, including volume expansion, color, and dislodgement from the enamel surface, was affected by the power of the laser. Charring was observed after 0.1 W, 0.2 W, and 0.4 W powered laser processing. The mean ablation depth of the enamel was limited to 20 µm. The pulp temperatures in all groups were about 42.5 °C during the laser processing, and an increase in laser power resulted in a rise in the maximum pulp temperature.

Conclusions: A picosecond laser can be used to remove resin cement rapidly and safely. The pulse impact effect and the carbonization effect were both present with laser processing.

Statement of problem: The vat polymerization-based 3-dimensional (3D) printing of dental materials necessitates a postpolymerization procedure to complete the fabrication of the printed device. A nitrogen-rich postpolymerization (NRPP) environment has been claimed to prevent the formation of an oxygen-inhibited layer, potentially improving material characteristics. However, a consensus on its impact on properties relevant to dental applications is lacking.

Purpose: The purpose of this systematic review and meta-analysis was to synthesize evidence comparing the chemical, physical, mechanical, and biological properties of 3D printed dental materials subjected to NRPP against conventional postpolymerization.

Material and methods: Comprehensive searches were conducted across MEDLINE (via PubMed), Web of Science, Scopus, Open Access Theses and Dissertations, and Google Scholar and using the manual method without language restrictions up to February 2024. Two reviewers screened the literature, assessed the risk of bias (RoB) using the QUality assessment tool for IN vitro studies (QUIN), and independently extracted data from eligible studies. Meta-analysis was undertaken by using a random-effects statistical model with the R-software program, and evidence certainty was rated via the grading of recommendations assessment, development, and evaluation (GRADE) approach.

Results: Of 275 articles, 14 in vitro studies with a medium RoB were included in the systematic review, with 8 eligible for meta-analysis. These studies involved 3D printed occlusal devices, implant guides, denture bases, interim crowns or fixed partial dentures, and orthodontic aligners. No statistically significant standardized mean difference (SMD) in material properties was found between with and without NRPP for water solubility, dimensional accuracy, water sorption, flexural modulus, flexural strength, hardness, or fracture toughness (P>.05). An exception was the degree of surface polymerization, with an SMD of 1.66% (95% CI, 0.56 to 2.76; I²=65%) favoring NRPP. The overall certainty of evidence was graded as low to very low.

Conclusions: NRPP does not significantly alter the physical, chemical, or mechanical properties of 3D printed dental materials except for a higher degree of surface polymerization in unpolished occlusal devices. The overall evidence certainty was rated as low to very low.

Statement of problem: Understanding the factors affecting loading-induced longitudinal peri-implant bone changes is crucial for successful implant-supported prosthetic treatment.

Purpose: The purpose of the study was to assess the biomechanical factors influencing 3-dimensional changes in the peri-implant bone volume and buccal bone thickness (BBT) with follow-up cone beam computed tomography (CBCT) images and finite element analysis (FEA).

Material and methods: Twelve study participants received dental implants without bone augmentation, resulting in the evaluation of 22 posterior dental implants. Each participant underwent 3 separate CBCT scans: the first at 3 months after loading, followed by scans at 15 months and 27 months after loading. CBCT images were superimposed at each interval with an image-processing software program. The peri-implant buccal bone area was determined as the volume of interest (VOI), and volumetric change in VOI and changes in BBT at 2, 4, and 6 mm below the implant platform were measured. FEA was performed to examine the mechanical stimulation in the VOI with occlusal force data obtained from the Dental Prescale. Interobserver reliability was evaluated by 3 experienced prosthodontists and dentists experienced with dental implants. Linear regression analyses were performed to evaluate the relationship between variables.

Results: Occlusal force and mechanical stimulation (strain energy density [SED]) in the VOI demonstrated a positive correlation; moreover, a positive correlation was observed between SED and bone volume loss in the VOI at 3 and 27months after loading. Similar correlations were observed with BBT, except at a depth of 6 mm under the implant platform. The interclass correlation coefficient values were 0.995 for volume and 0.982 for BBT, thereby indicating a high level of agreement among the observers' measurements.

Conclusions: This combined FEA and clinical study suggested that force-induced bone remodeling depends on the occlusal force in the early phases after superstructure placement.

Statement of problem: Recent studies have reported a significant correlation between the implant restoration contour and marginal bone loss (MBL). However, studies evaluating the relationship between the contour of implant restoration and marginal bone loss in subcrestally placed implants are lacking.

Purpose: The purpose of this retrospective study was to evaluate the relationship between the profile angle, measured from the implant platform and the adjacent crestal bone level as references, and the amount of MBL in subcrestally placed implants.

Material and methods: This retrospective study included 167 posterior single-tooth implant restorations with computer-aided design and computer-aided manufacturing (CAD-CAM) abutments by searching the electronic medical records of patients in regular maintenance. Among the 167 implants, 84 were placed more than 1 mm subcrestally in 76 patients, while 83 were placed equicrestally in 73 patients. The measurement of profile angles (PAs) was classified into 3 groups: EI Group: PA measured from the implant platform in equicrestally placed implants, SI Group: PA measured from the implant platform in subcrestally placed implants, and SB Group: PA measured from the adjacent bone crest in subcrestally placed implants. MBL changes were evaluated at different time points by measuring the distance between the implant shoulder and the first bone-to-implant contact. The Pearson correlation and linear regression analysis was used to evaluate the relationship between PA and marginal bone loss at different distance ranges. C-index analysis identified cut-off points of PA for 0 to 1, 1 to 2, and 2 to 3 mm distance ranges, and independent t tests evaluated statistical differences based on these cut-off points (α=.05 for all tests).

Results: EI and SB groups resulted in significant correlations between PA and MBL at 0 to 1 and 1 to 2 mm distance ranges (P<.05), but no significant correlation at 2 to 3 mm ranges (P>.05). In contrast, significant correlations were found between PA and MBL in the SI group at all distance ranges (0 to 1, 1 to 2, and 2 to 3 mm). In general, the SI groups showed smaller cut-off values than the EI or SB group at the corresponding distance ranges.

Conclusions: In subcrestally or equicrestally placed posterior single-tooth implants, the profile angles within 2 mm from the bone crest significantly correlated with marginal bone loss. When the profile angles were measured from the implant platform as references, the profile angle measured 0 to 3 mm from the reference correlated with marginal bone loss in subcrestally placed implants.