Journal of Esthetic and Restorative Dentistry最新文献

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.

Objectives: This study evaluated the effects of material and surface condition (glazed vs. polished after simulated occlusal adjustment) on translucency parameter, contact angle, and flexural strength of four monolithic zirconia.

Materials and methods: Disk-shaped specimens (n = 80, Ø12 × 1 mm) were fabricated from four monolithic zirconia materials: Prettau 4 Anterior (PA), Lava Plus (LP), Cercon hT (hT), and Cercon xT (xT). All specimens were glazed; half underwent simulated occlusal adjustment followed by polishing. Translucency was measured with a spectrophotometer, contact angle with a goniometer, and flexural strength using a piston-on-three-balls test. Data were analyzed via ANOVA.

Results: Translucency parameter values ranged from 3.9ᶜ (PA-Polished) to 6.9ᵃ (xT-Glazed), while contact angle (°) values ranged from 13.4ᵈ (hT-Glazed) to 43.7ᵃ (xT-Polished). Flexural strength (MPa) in the glazed condition was 410.4ᵇᶜ (PA), 577.5ᵇ (LP), 576.5ᵇ (hT), and 384.5ᵇᶜ (xT); under polishing, values were 333.1ᶜ (PA), 228.8ᶜ (LP), 856.0ᵃ (hT), and 287.1ᶜ (xT).

Conclusions: The xT group exhibited a higher translucency parameter compared to the LP and PA groups. Polishing increased the contact angle for all materials. Polishing subsequent to occlusal adjustment simulation preserved the flexural strength of two zirconia ceramics (PA and xT), resulted in a reduction in one (LP), and led to an increase in another (hT).

Objective: This study aimed to assess and compare the biaxial flexural strength (BFS) and microstructure of lithium-based CAD/CAM ceramics.

Material and methods: Eighty disc-shaped specimens were fabricated from four distinct Lithium-containing CAD/CAM ceramic blocks. Twenty samples were allocated to each category: IPS e.max CAD, GC LiSi Block, CEREC Tessera, and an unbranded ceramic. Universal testing machine equipment facilitated BFS testing in compliance with ISO 6872:2015 standards. Scanning electron microscopy (SEM) alongside energy-dispersive spectroscopy (EDS) techniques were employed for analysis of microstructural properties. One-way ANOVA followed by Tukey's post hoc test comprised the statistical evaluation, with a significance level of α = 0.05. Calculations of the Weibull modulus (m) and characteristic strength (σ₀) determined material reliability.

Results: CEREC Tessera showed the highest mean biaxial flexure strength and characteristic strength (biaxial flexure strength: 580.6 ± 208, σ₀ = 659 MPa). GC LiSi Block showed the lowest values (biaxial flexure strength: 351 ± 71 MPa, σ₀ = 381 MPa). Statistically significant differences appeared between GC LiSi Block and the other groups (p < 0.05). No differences appeared among IPS e.max CAD, CEREC Tessera, and the unbranded ceramic (p > 0.05). SEM analysis revealed rod-like lithium disilicate crystals in IPS e.max CAD and the unbranded material, whereas CEREC Tessera and GC LiSi Block exhibited spherical crystals, indicating substantial microstructural variation. Zirconia peaks appeared only in IPS e.max CAD.

Conclusions: Differences in biaxial flexure strength and microstructure appeared among the tested ceramics. GC LiSi Block showed the lowest mechanical performance. IPS e.max CAD, CEREC Tessera, and the unbranded material showed similar values. Both research hypotheses gained support.

Clinical significance: All tested ceramics exceeded the ISO 6872:2015 minimum BFS threshold of 300 MPa. This confirms their suitability for single-unit restorations. Unbranded lithium disilicate ceramics provide acceptable mechanical reliability. Their variability in composition and lack of regulatory oversight require caution in clinical applications.

Objective: To clinically evaluate the effect of the application of a Zirconia biovolume combined with surgical crown lengthening in patients with altered passive eruption, vertical maxillary excess, and excessive gingival display.

Clinical considerations: Three systemically healthy patients (two female, one male) presenting altered passive eruption (APE) Type 1 Subtype B with vertical maxillary excess (VME) and gingival display > 5 mm were treated with a protocol consisting in the preparation of a Zirconia biovolume to be applied in the anterior maxilla at the same time of surgical crown lengthening. Intra and extra oral scans were taken, as well as CBCT and printing of stereolithographic models in order to study the cases, plan the fabrication of the biovolume, and plan the surgical crown lengthening. Patients were followed for up to 12 months. Healing was uneventful in all three cases, and all patients were satisfied with the esthetic outcome in terms of surgical crown lengthening, gingival exposure, and lip repositioning.

Conclusion: These three cases show how the planning of cases with excessive gingival display, VME, and APE can be treated with a planned surgical procedure that will at the same time solve the problem of gingival exposure and the position and support of the upper lip.

Introduction: Ceramic laminate veneers (CLVs) play a vital role in esthetic dentistry; however, the impact of preparation design on clinical outcomes remains inconclusive.

Objectives: This prospective clinical study evaluated the clinical success of CLV restorations fabricated with different preparation techniques.

Methods: CLVs (N = 110; 55 minimally invasive, 55 prepless) were placed in 12 patients (7 female and 5 male). After 1 year, restorations were assessed via United States Public Health Service (USPHS) criteria. Chewing pressure was measured; restorations were checked for fractures, cracks, or debonding. Periodontal health was evaluated by probing depths; patient satisfaction was recorded using the Visual Analog Scale (VAS). Statistical analysis used chi-square and Mann-Whitney U tests (p < 0.05).

Results: No significant differences were observed in adaptation, color, form, or roughness (p > 0.05). Fractures were observed in 0% and 9.1% (n = 5), debonding in 0% and 1.8% (n = 1), and cracks in 3.6% (n = 2) and 0% of the minimally invasive and prepless groups, respectively. Fracture incidence differed significantly (p = 0.022). Chewing force showed no correlation with complications. Pocket depth changes were nonsignificant, and patient satisfaction was higher in the prepless group (median VAS = 10) than in the minimally invasive group (median = 9; p < 0.001).

Conclusions: Preparation type did not significantly affect esthetic or periodontal outcomes after 1 year. Complications were more common in prepless veneers, suggesting minimal prep might improve stability. Chewing forces did not significantly impact performance, indicating functional loads do not damage veneers.

Clinical significance: Both minimally invasive and prepless CLVs yield positive short-term outcomes. Yet, proper case selection and occlusal management are essential to prevent complications and secure long-term success.