Journal of Esthetic and Restorative Dentistry最新文献

Objectives: To present a fully digital workflow for mandibular stabilization that reproduces the conventional articulator-based process within a virtual environment, integrating patient-specific three-dimensional (3D) datasets and artificial intelligence (AI)-assisted alignment.

Clinical considerations: The workflow involves registration of intraoral scans, cone-beam computed tomography (CBCT), and/or facial scans to construct a unified virtual patient. Mandibular casts are mounted in centric relation on a virtual articulator using reference best-fit alignment. A virtual face-bow transfer aligns the maxillary cast to the articulator orientation plane based on anatomical landmarks from CBCT or facial scans. Stabilization splints are digitally designed with adjustable condylar guidance and anterior ramp inclination and fabricated via liquid crystal display (LCD) 3D printing with optimized orientation and post-processing. Clinical follow-up includes repeated digital centric relation bite registrations to monitor condylar position and confirm mandibular stability.

Conclusions: The fully digital workflow achieves mandibular stabilization while maintaining the biomechanical objectives of conventional methods. AI-assisted alignment, computer-aided design (CAD)-based splint design, and validated 3D printing parameters enhance precision, reproducibility, and clinical efficiency.

Clinical significance: This protocol provides a reproducible and clinically feasible approach to mandibular stabilization, bridging conventional occlusal principles with digital implementation, and establishing a foundation for future AI-integrated occlusion-centered therapy.

Objective: To evaluate the efficacy of a slow-resorbing small intestinal submucosa (SIS) membrane combined with freeze-dried bone allograft (FDBA) for horizontal bone augmentation in severely atrophic ridges.

Materials and methods: Six patients underwent horizontal ridge augmentation using FDBA and a slow-resorbing SIS membrane. Cone-beam computed tomography (CBCT) was used to measure horizontal bone width 2 mm apical to the alveolar crest at preoperatively (T0), immediately postoperatively (T1), and 4-6 months postoperatively (T2). Membrane integrity was assessed at the time of implant placement. Additionally, bone core biopsy was obtained for histomorphometric analyses.

Results: All surgical sites healed uneventfully. Horizontal bone gain was 4.74 ± 2.00 mm (T2-T0), with minimal resorption (0.37 ± 0.22 mm, T1-T2) and 95.08% ± 3.30% bone retention. Histomorphometry showed 44.6% new bone and 38.1% residual graft. All SIS membranes retained structural integrity at re-entry.

Conclusion: In this small case series, the SIS-GBR technique, combining a slow-resorbing SIS membrane with FDBA, provided preliminary evidence of substantial horizontal bone gain and favorable biocompatibility, with minimal short-term resorption.

Objectives: The aim of the study was to evaluate and compare the effect of thermal aging on the marginal and internal adaptation of veneered and monolithic zirconia (MZ) crowns.

Materials and methods: A maxillary central incisor abutment was digitally designed, fabricated using resin, and scanned for crown design. MZ (IPS e.max ZirCAD Prime Esthetic) and veneered zirconia (VZ; coping: Everest, KaVo; layering: IPS e.max Ceram) crowns were fabricated (n = 10). STL files were analyzed in Geomagic Design X to calculate root mean square (RMS) values within the selected marginal and internal regions before and after 10,000, 30,000, and 50,000 thermal cycles with superimposition. Data were analyzed using Shapiro-Wilk and Mann-Whitney U tests. The comparison of thermal aging treatments was evaluated using the Friedman and post hoc Wilcoxon signed-rank tests (p < 0.05).

Results: Significant differences were found between MZ and VZ crowns (p < 0.05). In the MZ group, marginal gaps increased from 104 μm (T0) to 115 μm (T3), and internal gaps from 122 μm (T0) to 146 μm (T3). In the VZ group, marginal gaps increased from 82 μm (T0) to 128 μm (T3) and internal gaps from 136 μm (T0) to 204 μm (T3). VZ crowns showed higher dimensional changes than MZ crowns.

Conclusions: Thermal cycling significantly affected the fit of zirconia crowns. VZ crowns exhibited greater dimensional changes after 30,000 and 50,000 thermal cycles, while MZ crowns maintained superior marginal fit during the same periods.

Clinical significance: This study highlights the influence of thermal aging on the marginal and internal adaptation of veneered and MZ crowns. VZ may be more susceptible to marginal or internal discrepancies after thermal aging, when compared with the MZ.

Objective: This study aimed to quantitatively evaluate the vertical and horizontal esthetic alignment parameters among young adults with high facial esthetic quality, thereby establishing reference benchmarks for natural facial symmetry and deviations.

Methodology: A total of 220 participants aged 18-25 years were included following strict esthetic and dental inclusion criteria. Standardized frontal facial photographs were obtained and analyzed using digital design software. Vertical midline relationships (pupil-incisor, philtrum-incisor, pupil-philtrum) and horizontal planes (pupil-incisal, pupil-commissure, commissure-incisal) were measured. Vertical deviations were categorized into five groups, and horizontal relationships were classified as parallel or non-parallel. Gender-based differences were assessed using chi-square analysis (p < 0.05).

Results: Reliability was excellent for vertical measurements (ICC = 0.93 intra-observer, 95% CI: 0.90-0.96; ICC = 0.88 inter-observer, 95% CI: 0.83-0.92) and substantial for horizontal plane assessments (Fleiss' kappa = 0.80; 95% CI: 0.72-0.87). Vertical midline alignment decreased progressively from the dental to the upper facial reference lines, with the highest coincidence observed in the philtrum-incisor relationship (48.6%) and the lowest in the pupil-philtrum alignment (23.4%). Horizontal plane parallelism showed a similar decreasing pattern toward upper facial structures. Gender comparisons revealed no significant differences in vertical midline alignment (p > 0.05). Commissure-incisal parallelism was significantly higher in males (p = 0.032), while other horizontal relationships showed no significant gender differences.

Conclusions: Vertical and horizontal esthetic relationships follow characteristic patterns across facial levels, reflecting the natural asymmetry of the human face. Gender-related differences were minimal and plane-specific rather than generalized. Objective digital measurements provide reliable reference data for clinicians in establishing facially driven esthetic treatment plans.

Clinical significance: This study provides reference data for natural facial symmetry in young adults, highlighting that minor asymmetries are normal and often esthetically acceptable. Clinicians should focus on harmony with facial flow rather than perfect geometric symmetry. From a clinical perspective, objective digital assessment of vertical and horizontal reference relationships may assist clinicians in selecting appropriate esthetic reference planes during facially driven treatment planning. Rather than defining strict normative values, these findings support an individualized approach that respects natural facial variability.

Background: Short dentin etching, or selective dentin etching (SDE) for 3 s, has emerged as a potential strategy to enhance the bond strength of adhesive systems while preserving dentin integrity. This systematic review aimed to evaluate whether a 3-s SDE protocol improves bond strength and interface durability compared to other adhesive strategies, such as conventional etch-and-rinse or self-etch protocols, with or without variations in etching time or application method.

Methods: A systematic search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines across PubMed, Scopus, Scielo, Embase, and ISI Web of Science, with no restrictions on publication year. Studies included human or bovine dentin as the substrate, employed SDE for 3 s before adhesive placement, and compared bond strength outcomes using conventional etching protocols. The outcome of interest was bond strength. Two independent reviewers screened and extracted data.

Results: Nine in vitro studies met the inclusion criteria. Evidence suggests that 3-s SDE improves immediate bond strength and, in some cases, long-term durability of universal adhesives by preserving hydroxyapatite and preventing over-demineralization of dentin. Excessive etching time (≥ 15 s) was associated with thicker, poorly infiltrated hybrid layers prone to hydrolytic degradation. The effect of SDE varied with adhesive type, presence of 2-hydroxyethyl methacrylate (HEMA), application method (with or without rubbing), solvent content, and hybrid layer composition, highlighting the importance of both material selection and etching technique.

Conclusions: SDE for 3 s enhances bonding performance and may increase the longevity of adhesive restorations. Clinicians should consider adhesive type, etchant viscosity, and substrate variability when applying this protocol. Future studies should explore standardized clinical protocols and long-term outcomes in vivo.

Purpose: The present study investigated the combined influence of four different scanning patterns and two intraoral scanning (IOS) technologies (Confocal Ultrafast Optical Sectioning vs. Active Triangulation with Structured Light) on the trueness and precision of both the intaglio and cameo surfaces of a maxillary reference denture.

Materials and methods: A maxillary complete arch reference denture was scanned using IOS technologies: Confocal Ultrafast Optical Sectioning (CUOS) and Active Triangulation with Structured Light (ATSL). Scanning was done 80 times with four strategies: APBOP (starting on the posterior intaglio surface), PABOP (beginning at the palatal aspect of the intaglio surface), BOPAP (starting on the cameo surface), and POBAP (beginning at the palatal cameo surface). Each strategy involved thorough scanning of various aspects, including occlusal surfaces, to capture the complete dentate arch. Distance-deviation values were calculated from comparisons with the STL reference model, and the data were analyzed using two-way ANOVA and Tukey's test.

Results: For the CUOS IOS technology, the POBAP scanning pattern exhibited the highest trueness (161 ± 6 μm) and precision (151 ± 7 μm), whereas the APBOP pattern showed the lowest trueness (183 ± 28 μm) and precision (171 ± 33 μm). For the ATSL IOS technology, the POBAP pattern also demonstrated the highest trueness (200 ± 32 μm) and precision (198 ± 32 μm), whereas the PABOP pattern showed the lowest trueness (241 ± 24 μm) and precision (239 ± 24 μm). The main effect of scanning technology was statistically significant (p < 0.001), with the estimated marginal mean (EMM) for CUOS being 171 μm, indicating greater trueness relative to ATSL (211 μm). A partial eta-squared value of 0.52 indicated that scanning technology explained approximately 52% of the total variation in trueness, representing a substantial effect size.

Conclusion: CUOS consistently exhibited superior trueness across all scanning patterns compared with ATSL.

Introduction: Management of missing anterior teeth can pose significant challenges for the orthodontist, as the maxillary incisors are key to esthetic orthodontic treatment planning. Two treatment modalities for patients that are unilaterally missing a maxillary lateral incisor that offer definitive functional and esthetic natural-tooth replacements for patients, regardless of age, are orthodontic canine substitution (OCS) and autotransplantation (AT) of a lower incisor. Using validated indices and an electronic questionnaire, the purpose of the study was to assess, objectively and subjectively, whether AT of a lower incisor or unilateral OCS offers patients who present with a unilateral missing maxillary lateral incisor a better esthetic result.

Methods: An orthodontist, periodontist, restorative dentist, and prosthodontist evaluated intraoral frontal images of 55 patients who were missing a single maxillary lateral incisor and were treated with unilateral OCS (25) or AT of a lower incisor (30) using the Pink and White Esthetic Indices. In addition, the specialists evaluated 30 finished orthodontic cases with no missing teeth as controls. An electronic survey was distributed to orthodontists, general dentists, and laypeople to gauge subjective opinions on the esthetic results of OCS versus AT.

Results: Lower incisor autotransplantation and unilateral orthodontic canine substitution had statistically significant lower esthetic scores than cases without missing teeth. The scores of AT and OCS were not significantly different from one another. Electronic survey data showed that dental providers find finished orthodontic cases the most esthetic, followed by lower incisor AT and unilateral OCS. Laypeople find unilateral OCS significantly more esthetic than both control and AT cases.

Conclusions: Compared to unilateral OCS, lower incisor AT offers comparable esthetic outcomes and should be considered in cases of unilateral missing maxillary lateral incisors.

Clinical significance: This study demonstrated that orthodontic space closure and dental autotransplantation can be acceptable treatment solutions for growing patients with a unilateral missing maxillary lateral incisor. Esthetic outcomes in the maxillary anterior region can impact the psychological status of a patient during an important developmental stage.

Objective: This in vitro study aimed to evaluate the effects of substructure color and restoration thickness on the final color of shade-gradient ultra-translucent zirconia ceramics.

Material and methods: A total of 180 flat-shaped ultra-translucent zirconia specimens (5Y-PSZ) with thicknesses of 0.4, 0.6, and 0.8 mm (n = 60) were fabricated and cemented onto composite substructures in six colors (A1, A2, B1, B2, C2, D2). Color parameters were measured before and after cementation, and color differences (ΔE₀₀) were calculated using the CIEDE2000 formula. The data were evaluated using the two-way repeated measures of ANOVA, Kruskal-Wallis, Tukey HSD, and Bonferroni tests (α = 0.05).

Results: Substructure color and restoration thickness had significant effects on ΔE₀₀ (p < 0.001) after cementation, with values exceeding the acceptability threshold (1.8) in all groups. Before and after cementation, A2 remained below the acceptability threshold relative to target color A1 and B2 achieved acceptable color matching with increased thickness.

Conclusions: Restoration thickness and substructure color significantly influenced the final color of shade-gradient zirconia ceramics. A2 provided better color matching, while B2 required a minimum thickness of 0.8 mm for acceptable results.

Clinical significance: Increased zirconia thickness enhances masking of darker substructures. Additionally, the influence of the substructure color must be carefully considered, particularly in thinner ultra-translucent zirconia ceramics, to ensure predictable, harmonious color matching.

Statement of problem: Additively manufactured interim restorative materials are being employed to meet contemporary esthetic demands, yet the longevity of their optical characteristics remains uncertain.

Objective: To assess the impact of material composition and manufacturing method on the optical stability of different additively manufactured interim restorative resins under in vitro aging methods and compare these properties to those of milled hybrid ceramic blocks.

Materials and methods: A total of 240 disc-shaped specimens (diameter 10.00 ± 0.05 mm, thickness 1.10 ± 0.05 mm) were fabricated utilizing four additively manufactured resin-based and two milled hybrid ceramic blocks. Following standardized finishing and polishing processes, the specimens were aged in coffee at 55°C, grape juice at 5°C, deionized water at 25°C, or thermocycled between 5°C and 55°C. Color stability (ΔE₀₀) and relative translucency parameter (RTP₀₀) were evaluated. Data was analyzed with two-way ANOVA and Tukey's post-hoc tests (α = 0.05).

Results: Material type significantly affected the color and translucency following aging (p < 0.001). Among additively manufactured materials, Primeprint Temp demonstrated the least color change (ΔE₀₀ = 4.30 ± 1.10), while Ceramic Crown Resin showed the most significant discoloration (ΔE₀₀ = 13.52 ± 1.40). Furthermore, the milled hybrid ceramic material (Enamic) exhibited the lowest overall color change across all tested materials. Ceramic Crown Resin exhibited the most significant reduction in the relative translucency parameter (ΔRTP₀₀ = -2.70 ± 0.55), exceeding the acceptability threshold of 2.6 following immersion in coffee.

Conclusions: Primeprint Temp demonstrated superior color and translucency stability relative to the other materials examined, whereas Ceramic Crown Resin showed the least stability, particularly under the conditions of coffee immersion.

Clinical significance: Understanding the optical stability of contemporary interim additively manufactured resins facilitates enhanced esthetic stability between sessions and minimizes the necessity for repolishing or remaking interim restorations. Patients who frequently consume hot, staining beverages should be warned about potential discoloration, especially when utilizing resin-based materials for long-term use.

Objective: To investigate the effects of three bleaching protocols on the color stability and surface roughness of enamel previously treated with a water-based, ammonia-free silver fluoride solution (Riva Star Aqua).

Materials and methods: Eighty-eight human enamel/dentin specimens were demineralized and treated with Riva Star Aqua, divided into four groups (n = 22): Control (no bleaching), home bleaching with 15% hydrogen peroxide (HP), in-office bleaching with 40% HP, and laser-activated bleaching with 46% HP. Color differences (ΔE₀₀) were measured at different stages, and the surface roughness (Ra) was evaluated before and after bleaching. Data were analyzed using two-way repeated measures ANOVA and Fisher's PLSD test (α = 0.05).

Results: The application of Riva Star Aqua caused perceptible discoloration in all groups. Following bleaching, all three active protocols resulted in significant color correction compared with the control group (p < 0.05). The final color differences (ΔE₀₀ Final) for Opalescence Boost (6.82 ± 0.49), Opalescence Home (8.84 ± 0.42), and Laser White 20 (8.83 ± 0.37) were statistically comparable (p < 0.05). At the same time, the control group showed significantly high ΔE₀₀ Final (10.75 ± 0.29). Regarding surface roughness, all bleaching groups showed a significant increase in Ra values (p < 0.05) compared to baseline, with significant differences between Laser White 20 and the other bleaching protocols (p < 0.05).

Conclusion: Bleaching effectively reversed the discoloration caused by ammonia-free silver fluoride. While all tested protocols achieved comparable final color correction, the laser-activated protocol resulted in significantly less alteration of surface roughness than the conventional in-office and at-home bleaching protocols.