Journal of Esthetic and Restorative Dentistry最新文献

Background: Preheating resin-based composites (RBC) has been shown to enhance their mechanical and bonding properties. Nevertheless, the effect of preheating RBCs on the performance of orthodontic lingual fixed retainers has been scarcely reported.

Objectives: The aim of this in vitro study was to investigate the effect of preheating flowable RBCs and the types of RBC and wire on the load at failure.

Methods: A total of 64 blocks of resin-embedded pairs of lower incisors were divided into four groups according to RBC/wire types (Tetric N-Flow Bulk Fil restorative (TNF) vs. Transbond LR orthodontic (TRL) composites/Bond-A-Braid braided (B) vs. Ortho-Flex-Tech flexible (O) retainer wires). Each group was then subdivided into room temperature at 25°C (RT) and preheated temperature at 50°C (H) subgroups (N = 16, n = 8). After bonding the wires, the test blocks were subjected to load-to-failure testing, and the maximum load was recorded (Lmax). Statistical analysis using 3-way ANOVA with point-biserial correlations was completed (p < 0.05).

Results: Temperature significantly increased L_max (p < 0.001). Mean L_max of TRL/B was greater than TNF/O but was not statistically significant (p > 0.05). There was no statistically significant interaction between the variables: RBC, wires, and/or temperature (p > 0.05).

Conclusion: The study shows preheating RBCs improves their load capacity, reducing lingual retainer adhesive debonding. Therefore, preheating flowable RBCs is effective for retention. Future research should explore different preheating temperatures and long-term outcome conditions.

Objective: To evaluate the marginal adaptation and margin trueness of lithium disilicate glass-ceramic (LDS) and glass-filler reinforced composite resin (CR) onlays fabricated using three different finish lines and two chairside CAM units (4- and 5-axis).

Methods: LDS (e.max CAD) and CR (Tetric CAD) onlays were fabricated on butt joint, chamfer, and bevel finish lines using 4-axis (CEREC MC XL) and 5-axis (Programill One) chairside CAM units (N = 120). Onlays were scanned for margin trueness and marginal adaptation analyses. Data were analyzed with three-way ANOVA and Tukey B post hoc test (α = 0.05).

Results: A significant interaction was found among finish line, material, and CAM unit for marginal adaptation and margin trueness (p < 0.001). Bevel had the highest marginal adaptation; chamfer the lowest. Butt joint showed the highest margin trueness; bevel the lowest. CR onlays had better marginal adaptation than LDS with bevel finish lines, regardless of CAM unit. Overall, 5-axis CAM units yielded better margin trueness.

Conclusions: Finish line design, restorative material, and CAM unit affected the marginal adaptation and margin trueness. The bevel finish line yielded the highest marginal adaptation and the chamfer the lowest, regardless of material or CAM unit. Conversely, the butt joint showed the highest margin trueness, and the bevel the lowest.

Clinical significance: Finish line design, material type, and CAM unit selection may affect marginal adaptation and margin trueness of onlays. A bevel finish line may improve marginal adaptation, while a butt joint finish line may enhance margin trueness. Using a 5-axis CAM unit can improve trueness, particularly with bevel and chamfer finish lines and composite resin materials.

Objectives: The aim of this review was to assess the long-term clinical and aesthetic outcomes of implants placed with immediate and early protocols in the anterior maxilla with a follow-up greater than 5 years.

Materials and methods: An electronic search in Pubmed, Embase, CINAHL via EBSCO, and the Cochrane database was performed to identify studies on single-tooth implants placed with immediate (Type 1) and early (Type 2) placement protocols in the anterior maxilla that reported outcomes on aesthetics, hard and soft tissue changes with a mean follow up ≥ 5 years.

Results: Fifteen studies on immediate and early protocol single implants placed in the anterior maxilla with a ≥ 5 year follow up were included. A lack of studies comparing the two placement protocols was observed. Soft tissue changes were found to be acceptable for immediately placed implants, with seven studies reporting mean mid-buccal gingival recession of 0.15 ± 0.27 mm and mean papillary height loss of 0.07 mm mesial and 0.20 mm distal after a follow up of ≥ 5 years. Advanced buccal recession (> 1 mm) occurred in 12.17% of cases. Ten of the 15 included studies reported a mean bone loss of 0.68 ± 0.42 mm. Favorable aesthetic outcomes were reported by most studies with a 2.83% incidence of aesthetic failures (aesthetic score < 50% of maximum achievable). The few studies that reported on patient-centered outcomes showed a high level of patient satisfaction post treatment.

Conclusions: Immediate and early implant placement protocols showed acceptable soft tissue and aesthetic outcomes, with suboptimal aesthetic outcomes reported in 2.83% of cases. More long-term follow-up studies are necessary to identify factors that influence aesthetic outcomes in implants placed with various placement protocols in the anterior maxilla.

Objective: Polyethylene fiber (PF) and fiberglass (FG) posts have been recommended for intraradicular anchorage when there is a significant loss of coronal structure. However, few studies have evaluated their performance in anterior teeth combined with direct restorations as an alternative to single crowns. The objective of this study is to compare the fracture resistance and failure modes of endodontically treated anterior teeth restored with a FG post, a biomimetic technique using PF, and a direct resin composite (RC).

Materials and methods: Forty sound upper central incisors were selected, endodontically treated, standardized for clinical crown height, and randomly distributed into four groups (n = 10): Positive control: teeth with an intact clinical crown, subjected only to access and endodontic treatment (CT), RC, PF, and FG post. Restorations were performed according to specific clinical protocols using a universal adhesive system. Fracture resistance was tested on a universal testing machine under compressive load at a 45° angle (1 mm/min). Fracture patterns were analyzed under a stereomicroscope and classified as either repairable or catastrophic. Data were analyzed using ANOVA and Fisher's exact test (α = 0.05).

Results: The CT group exhibited the highest mean resistance (840 N), followed by PF (740 N), FG (700 N), and RC (480 N), with a significant difference between the RC group and the others (p < 0.001). No significant difference was found among the groups regarding the failure mode (p > 0.05).

Conclusion: FGs and PFs provided greater fracture resistance and a higher incidence of repairable fractures, with more favorable outcomes than when the procedure is performed exclusively with RC restorations.

Objective: This double-blind, randomized clinical trial evaluated the effect of ozonized sunflower oil on tooth sensitivity, color change, and patient perception during at-home bleaching with 10% hydrogen peroxide.

Clinical considerations: Forty participants were randomly assigned to receive ozonized or nonozonized sunflower oil, applied in trays for 1 min after each bleaching session (30 min daily for 21 days). Sensitivity was assessed daily using visual and numerical scales. Tooth color was measured at baseline, 1 week, and 1 month after treatment using a spectrophotometer (ΔEab, ΔE00, ΔWID) and a visual shade guide (ΔSGUs). Patient perception was evaluated through Likert-scale questionnaires.

Conclusions: Overall, 72.5% of participants experienced sensitivity, with no significant difference in intensity (p = 0.536) or duration (p = 0.256) between groups. Color changes were similar (p > 0.05), although ΔEab and ΔE00 values decreased at 1 month (p = 0.010 and p = 0.026). Ozonized oil had an unpleasant taste (p = 0.002) and odor (p = 0.010). The use of ozonized sunflower oil did not reduce bleaching-related sensitivity or enhance whitening effectiveness, and its poor sensory properties may limit patient acceptance.

Objective: This study aimed to develop and evaluate deep learning-based models for estimating CIELAB tooth color coordinates from standardized extraoral photographs, using in vivo spectrophotometric measurements as the reference standard, to provide practical and validating support for clinical shade selection in restorative dentistry.

Materials and methods: A total of 1031 labeled and cropped tooth images were obtained from high-resolution extraoral photographs of 102 participants. In vivo CIELAB color coordinates (L*, a*, b*, C*, h°) were recorded from the maxillary anterior teeth using the VITA Easyshade V spectrophotometer. Five convolutional neural network (CNN) architectures (CustomCNN, ResNet18, EfficientNetB0, DenseNet121, and MobileNetV2) were trained using two types of input: preprocessed tooth photographs (cropped, resized, and normalized) and their corresponding anatomical positions (one-hot encoded). The performance of this combined-input model was evaluated using mean absolute error (MAE), coefficient of determination (R²), and estimation accuracy based on the ΔE ≤ 2 clinical threshold. Intermodel performance differences were analyzed using one-way ANOVA (p < 0.001). The best-performing model was further trained to classify VITA Classical shade codes from spectrophotometric color coordinates to assess clinical applicability.

Results: Among the models tested, MobileNetV2 achieved the best performance, with a MAE of 0.0593 and accuracy exceeding 94% when estimated CIELAB color coordinates from extraoral photographs were compared with in vivo spectrophotometric measurements (reference standard) using the ΔE ≤ 2 clinical threshold. No significant differences were found between MobileNetV2, DenseNet121, and ResNet18, and all three models significantly outperformed EfficientNetB0 and CustomCNN (p < 0.001). Estimation accuracy was highest for C*(chroma) and h°(hue) values, while slightly lower performance was observed for L*(lightness) and b* values. Anterior teeth exhibited higher accuracy than posterior teeth, likely due to more favorable image quality and light exposure.

Conclusion: AI-based models, particularly MobileNetV2, demonstrated high agreement with spectrophotometric reference measurements in estimating CIELAB tooth color coordinates from standardized extraoral photographs. These findings suggest their potential to support consistent and practical shade selection in esthetic restorative dentistry.

Clinical significance: These results suggest that AI models have the potential to be applied in clinical shade selection procedures, providing a supportive approach that may contribute to improved consistency and assist decision-making in esthetic dentistry.

Objective: The use of narrow-diameter implants has emerged as a strategy to compensate for the reduced bone dimensions of maxillary lateral incisor agenesis (MLIA). This study integrates finite element analysis (FEA) and systematic review (SR) to assess the biomechanical and clinical viability of implant-supported crowns in MLIA scenarios.

Materials and methods: Three-dimensional FEA were built, comprising a control and an atrophic model representative of an MLIA case. Simulations were performed using implants with varying diameters and materials. The risk of implant and abutment mechanical failure and bone resorption were evaluated. The SR was designed to evaluate the consistency between in silico predictions and clinical outcomes.

Results: Reduced implant diameter was associated with an increased risk of implant fracture and bone resorption. All implants and abutments in the simulated models exhibited stress values below the critical threshold for titanium and zirconia failure, indicating a low mechanical failure risk under simulated conditions. Additionally, among the 25 studies included in the SR, 19 reported successful outcomes for implant therapy, but no zirconia implants were identified.

Conclusions: Titanium implants with regular diameter combined with hybrid abutments demonstrated favorable biomechanical behavior and seem a reliable option for MLIA rehabilitation, offering both structural integrity and esthetic benefits.

Clinical significance: The implant-prosthetic rehabilitation of MLIA has demonstrated high reliability and predictability in both esthetic and functional outcomes, especially when performed through a multidisciplinary approach involving orthodontics, periodontics, implantology, and prosthodontists. Long-term studies are still necessary to validate the longevity and performance of zirconia implants in MLIA.

Objective: Treating patients with worn dentition is complex and requires comprehensive consideration of function, esthetics, and tissue preservation. An important aspect of contemporary dentistry is to be conservative and have proper protocols to plan and treat these situations while protecting the remaining tooth structures. The purpose of this article is to present an organized and conservative digitally aided treatment protocol for patients with worn dentition, which takes into account pre-established parameters that allow increasing the occlusal vertical dimension following the GRS Concept-the Generated restorative space.

Clinical considerations: This protocol emphasizes the need to assess each clinical scenario and plan prosthetic designs that increase predictability; it also establishes guidelines that promote minimal invasion, proper material selection, and an approach guided by the existing wear pattern, patient-specific factors, and biological preservation.

Clinical significance: Properly planned treatment and the use of digital technology will enable clinicians to be more conservative and retain the largest amount of the residual tooth structure in wear patients.

Conclusion: Treating patients with generalized worn dentition is a challenging task, and proper treatment planning and execution are needed. Digital assets such as the "cross-sectional view" in CAD software allow the clinician to analyze the generated restorative space, be more conservative, and support the long-term success and predictability of the restorations.

Objective: To describe a hybrid approach for a metal-ceramic anterior crown, combining traditional ceramic layering with a chairside staining technique guided by recipes generated using an artificial intelligence-based software.

Clinical considerations: The clinical case presented a step-by-step protocol from both laboratory and clinical perspectives for the replacement of a single anterior metal-ceramic crown in a 32-year-old male patient dissatisfied with crown color and gingival darkening. Clinical examination revealed a slight color mismatch, shape discrepancy, and inadequate gingival adaptation, with a metal post-and-core contributing to the darkened appearance. The final color reproduction was achieved using a chairside staining approach (Vintage Art Universal, Shofu, Kyoto, Japan) guided by Matisse recipes (Labmatisse BV, Wijchen, The Netherlands). This approach reduced treatment time and cost while achieving an optimal esthetic outcome on the first attempt, with a color difference (0.5 units) below the ΔE₀₀ perceptibility threshold, eliminating the need for additional color corrections.

Conclusions: The hybrid approach proved feasible for integrating laboratory procedures with chairside staining protocols. This strategy resulted in an esthetically satisfactory outcome for an anterior metal-ceramic crown, highlighting the potential of artificial intelligence-driven staining solutions.

Clinical significance: The artificial intelligence-assisted chairside staining approach offers clinicians and dental technicians a practical tool for achieving accurate color reproduction in ceramic materials. Applicable to both layered and monolithic restorations, this technique enhances esthetic outcomes while improving treatment efficiency.