Search

Purpose: To evaluate the effect of different veneering ceramics and veneering techniques on the bond strength to zirconia., Materials and Methods: 3Y-TZP zirconia blocks were sliced into 60 slabs, polished, and sintered. Each slab received one ceramic cylinder (Ø = 3.4 mm, 5 mm-high), according to the veneering ceramic type (feldspathic-FEL or lithium disilicate-based-LD) and the veneering technique (file-splitting with resin-based luting agent-RC, file-splitting with fusion ceramic-FC, or heat-pressing-HT), which resulted in six groups: FEL-RC, FEL-FC, FEL-HT, LD-RC, LD-FC, LD-HT. After preparation, the samples were immersed in distilled water for 24 h before the shear bond strength (SBS) test. The failure modes were classified as adhesive, predominantly adhesive, or cohesive. Representative failure mode images were taken in a Scanning Electron Microscope. The SBS data were analyzed by two-way ANOVA and Tukey's test., Results: Both type of veneering ceramic and technique affected the bond strength. FC led to the highest SBS values. RC and HP provided similar results when compared within each veneering ceramic. Lithium disilicate achieved lower bond strength than feldspathic ceramic when the heat-pressing technique was applied. The most frequent failure modes were predominantly adhesive and adhesive for FEL and LD, respectively., Conclusion: File-splitting with fusion ceramic provided the highest adhesion to zirconia when feldspathic or lithium disilicate-based ceramics were used. The heat-pressing technique for veneering with lithium disilicate significantly decreased the bond strength when compared to the feldspathic ceramic., (© 2023 by the American College of Prosthodontists.)

Objective: To understand the stress development in porcelain-veneered zirconia (PVZ) and porcelain-veneered lithium disilicate (PVLD) crowns with different veneer/core thickness ratios and cooling rates. To provide design guidelines for better performing bilayer restorations with the aid of Viscoelastic Finite Element Method (VFEM)., Methods: The VFEM was validated by comparing the predicted residual stresses with experimental measurements. Then, the model was used to predict transient and residual stresses in the two bilayer systems. Models with two different veneer/core thickness ratios were prepared (2:1 and 1:1) and two cooling protocols were simulated (Fast: ∼300 °C/min, Slow: ∼30 °C/min) using the heat transfer module, followed by stress analysis in ABAQUS. The physical properties of zirconia, lithium disilicate, and the porcelains used for the simulations were determined as a function of temperature., Results: PVLD showed lower residual stresses than PVZ. The maximum tensile stresses in PVZ were observed in the cusp area, whereas those in PVLD were located in the central fossa. The 1:1 thickness ratio decreased stresses in both layers of PVZ. Slow cooling slightly decreased residual stresses in both systems. However, the cooling rate effect was more evident in transient stresses., Significance: Slow cooling is preferable for both systems. A thinner porcelain layer over zirconia lowers stresses throughout the restoration. The different stress distributions between PVZ and PVLD may affect their failure modes. Smaller mismatches in modulus, CTE, and specific heat between the constituents, and the use of low T g porcelains can effectively reduce the deleterious transient and residual tensile stresses in bilayer restorations., (Copyright © 2021 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)

Aim: This manuscript aims to evaluate, through a scoping review, current knowledge of the biomechanical behavior, materials, preparations, and limitations of occlusal veneers., Background: Occlusal veneers are a minimally invasive alternative for the additive restoration of posterior teeth with significant loss of the occlusal structure. This type of restoration has been emerged in recent years as an alternative to invasive treatment, which in the same way seeks to restore the structure of the posterior teeth. All this is because in recent years restorative dentistry has focused a large part of its objectives on conservative therapies., Review Results: Five electronic databases-PubMed, Cochrane, LILACS, EMBASE, and Google Scholar-were searched. Title and abstracts were independently screened by three reviewers, followed by a full-text review. A total of 42 articles met our inclusion criteria; most of these studies were in vitro ( n = 35) and other studies were clinical studies ( n = 7). These in vitro studies included 21 studies that analyzed the type of preparation and 6 studies that evaluated the limitations of occlusal veneers., Conclusion: Thicknesses between 0.7 and 1.0 mm are recommended for ceramic materials; in addition, thicknesses less than 0.7 mm are recommended to use polymeric materials. The materials used for this type of restoration are plastic- and ceramic-based materials, whose load resistance values were found to exceed 2000 N in most studies. It is recommended to carry out a minimally invasive preparation or not to carry out a dental preparation, as long as there is a peripheral enamel to make an external bevel that redirects the eccentric forces to the axis of the tooth., Clinical Significance: Restorative dentistry has moved toward conservative treatments with the least amount of dental tissue being removed. Occlusal veneers appear to be a conservative option in the reconstruction of tooth tissues lost due to tooth wear and in cases where it is necessary to restore or increase the vertical dimension.

Purpose: To evaluate the clinical outcomes of minimally invasive ceramic restorations executed by dentists with different levels of experience., Methods: Sixteen professionals were divided into 4 groups according to their experience levels. These included G1: up to 2 years since graduation, G2: 2-5 years, G3: 5-10 years, and G4: more than 10 years. All professionals were trained to follow the same standardized clinical protocol, but were unaware of the research objectives. A single evaluator followed the clinical treatments and recorded the complications and errors that occurred during the execution of the protocol. Ninety-one full crowns, 137 veneers, and 46 no-preparation veneers were prepared from lithium disilicate. Follow-ups were performed immediately and at 30, 180, and 360 days after the cementation and the evaluation based on the modified United States Public Health Service criteria. Ceramic chipping/fracture and debonding were considered failures. Fractures were replicated and submitted to fractographic analysis., Results: The highest number of failures were found in G1 followed by G3 and the lowest number of failures were found in G2. The level of success was 94% after 360 days. The fractographic analysis demonstrated the external surface of restorations as the critical area and suggested that failures might occur due to noncompliance with the clinical protocol. There was no correlation between professional experience and number of failures or patient satisfaction., Conclusions: Professional experience was not a decisive for patient satisfaction and success of minimally invasive ceramic restorations, and noncompliance with the clinical protocol was associated with early ceramic restoration failures.

In this study, the effects of boric acid addition to the veneer ceramics and treatment of the ceramic cores immersed in potassium nitrate solution were evaluated to reduce the micro cracks that may occur in the internal structure of the ceramic, increase the mechanical properties and improve the chemical bonding strength of core ceramics. In the data obtained after the experiment, the average MPa values showed statistically significant differences according to the groups (p⟨0.001). The average value in the control group (C) was lower than the others. There was no statistically significant between the mean values of the boric acid application in the veneer ceramic (IB) group and zirconia core immersed in the potassium nitrate solution (IN) group. The highest mean values were observed between the veneer ceramic and the zirconia core by application of boric acid and potassium nitrate (IBN) group. As a result potassium nitrate and boric acid application affects the bond strength between zirconia core and veneer ceramic and increases mechanical properties of ceramics., (Copyright© 2020 Dennis Barber Ltd.)

Adhesion plays a major role in the bonding of dental materials. In this study the adhesion of two glass-ceramic systems (IPS e.max and VITABLOCS) to a zirconia sintered substrate using a glass (for IPS e.max) and resin (VITABLOCS) before and after exposure to ageing for 14 days in distilled water at 37 °C are compared using two interfacial fracture mechanics tests, the 3 point bend Schwickerath (Kosyfaki and Swain, 2014; Schneider and Swain, 2015) and 4 point bend (Charalambides et al., 1989) approaches. Both tests result in stable crack extension from which the strain energy release rate (G, N/m or J/m 2 ) can be determined. In the case of the 3 PB test the Work of Fracture was also determined. In addition, the Schwickerath test enables determination of the critical stress for the onset of cracking to occur, which forms the basis of the ISO (ISO9693-2:2016) adhesion test for porcelain ceramic adhesion to zirconia. For the aged samples there was a significant reduction in the resin-bonded strengths (Schwickerath) and strain energy release rate (both 3 and 4 PB tests), which was not evident for the glass bonded specimens. Critical examination of the force-displacement curves showed that ageing of the resin resulted in a major change in the form of the curves, which may be interpreted in terms of a reduction in the critical stress to initiate cracking and also in the development of an R-curve. The extent of the reduction in strain energy release rate following ageing was greater for the Schwickerath test than the Charalambides test. The results are discussed in terms of; the basic mechanics of these two tests, the deterioration of the resin bonding following moisture exposure and the different dimensions of the specimens. These in-vitro results raise concerns regarding resin bonding to zirconia., Statement of Significance: The present study uses a novel approach to investigate the role of ageing or environmental degradation on the adhesive bonding of two dental ceramics to zirconia. This continues to be a major clinical problem but current approaches, till now, have relied upon a myriad of strength based tests to quantify the extent of environmental degradation with time. In this paper we use two fracture mechanics approaches, based upon simple 3 and 4 point bend testing procedures that enable stable debonding crack extension to occur. The paper provides a more critical approach to evaluate the role of environmental degradation of adhesion for dental materials., (Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

A survey of the development of dental ceramics is presented to provide a better understanding of the rationale behind the development and clinical indications of each class of ceramic material. Knowledge of the composition, microstructure, and properties of a material is critical for selecting the right material for specific applications. The key to successful ceramic restorations rests on material selection, manufacturing technique, and restoration design, including the balancing of several factors such as residual stresses, tooth contact conditions, tooth size and shape, elastic modulus of the adhesives and tooth structure, and surface state., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Few studies have focused on the interface fracture performance of zirconia/veneer bilayered structure, which plays an important role in dental all-ceramic restorations. The purpose of this study was to evaluate the fracture mechanics performance of zirconia/veneer interface in a wide range of mode-mixities (at phase angles ranging from 0° to 90°), and to examine the effect of mechanical properties of the materials and the interface on the fracture initiation and crack path of an interfacial crack. A modified sandwich test configuration with an oblique interfacial crack was proposed and calibrated to choose the appropriate geometry dimensions by means of finite element analysis. The specimens with different interface inclination angles were tested to failure under three-point bending configuration. Interface fracture parameters were obtained with finite element analyses. Based on the interfacial fracture mechanics, three fracture criteria for crack kinking were used to predict crack initiation and propagation. In addition, the effects of residual stresses due to coefficient of thermal expansion mismatch between zirconia and veneer on the crack behavior were evaluated. The crack initiation and propagation were well predicted by the three fracture criteria. For specimens at phase angle of 0, the cracks propagated in the interface; whereas for all the other specimens the cracks kinked into the veneer. Compressive residual stresses in the veneer can improve the toughness of the interface structure. The results suggest that, in zirconia/veneer bilayered structure the veneer is weaker than the interface, which can be used to explain the clinical phenomenon that veneer chipping rate is larger than interface delamination rate. Consequently, a veneer material with larger fracture toughness is needed to decrease the failure rate of all-ceramic restorations. And the coefficient of thermal expansion mismatch of the substrates can be larger to produce larger compressive stresses in the veneer., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objective: The present paper aims to demonstrate the incorporation of the double monolithic protocol (DMP) into a chairside digital workflow to reproduce the fluorescence properties of natural teeth with chairside monolithic restorations when exposed to different light sources. Clinical Considerations: A female patient reporting dissatisfaction with her upper anterior teeth was rehabilitated using seven veneers and a three‐element bridge. The DMP was applied to the bridge, which consisted of a primary lithium disilicate framework to which leucite‐reinforced glass ceramic veneers were cemented. The fluorescence of the different substrates and ceramic restorations was evaluated throughout the rehabilitation process, under 365 and 405 nm light. Conclusions: The DMP allows chairside procedures to be optimized by achieving predictable, mechanically resistant, and esthetic restorations. Clinical Significance: The DMP is a new chairside solution for developing ceramic restorations with optimal esthetics and combined mechanical properties, eliminating the need for sintering or glazing procedures. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Material and Methods Results Conclusions Clinical Significance To analyze survival and complication rates for anterior and premolar laminate‐veneers out of different ceramic materials (feldspathic, leucite‐reinforced glass–ceramic [LRGC], lithium‐disilicate [LDS] and zirconia).A systematic literature search was conducted across multiple databases for clinical studies on ceramic laminate‐veneers with a minimum‐follow‐up of ≥ 1 year. The date of last search was on February 19, 2024. Survival, technical, esthetic and biological events were assessed for different laminate‐veneer materials at three observation periods (short‐ [1–3 years], mid‐ [4–6 years] and long‐term [≥ 7 years]).Twenty‐nine studies were included. Meta‐analysis revealed a pooled survival‐rate of 96.13% for feldspathic, 93.70% for LRGC and 96.81% for LDS at 10.4 years. No difference was found between materials. Complication rates (technical/esthetic/biological) were as follows: Feldspathic: 41.48%/19.64%/6.51%; LRGC: 29.87%/17.89%/4.4%; LDS: 6.1%/1.9%/0.45% at 10.4 years. Zirconia showed a 100% survival‐rate with no complications at 2.6 years. No long‐term data was available for zirconia.Feldspathic, LRGC and LDS laminate‐veneers showed high survival‐rates at long‐term observation. LDS slightly outperforms feldspathic and LRGC laminate‐veneers with lower long‐term complication rates. More studies providing long‐term data on zirconia laminate‐veneers are needed.Ceramic laminate‐veneers are a reliable treatment option. LDS may be preferred as a restorative material for long‐term success. [ABSTRACT FROM AUTHOR]

Background: When discolored teeth are repaired with porcelain veneers, the thickness of the restorations should be increased appropriately using opaque porcelain and bonded by applying opaque luting resin cement to cover discolored substrates. However, its impact on the opalescent performance has not been reported yet. Purpose: To analyze the effects of opacity, body porcelain layer thickness, and luting resin cement on the opalescence properties of porcelain veneer restorations for discolored teeth. Methods: Ninety IPS d. SIGN A3 porcelain veneer specimens were prepared via powder–paste coating and sintering. Specimens were divided into three groups according to ceramic type and cement used or not: body porcelain group as control, body/opaque porcelain group and body/opaque porcelain–resin cement composite group. Each group was subdivided into three subgroups based on the thickness, 0.50, 0.75, and 1.00 mm (n = 10). Variolink N Bleach XL luting resin cement with thickness of 0.1 mm was applied to the bottoms of body/opaque porcelain specimens to produce body/opaque porcelain–resin cement composites. The opalescence (OP) values were calculated and the micromorphological characteristics were analyzed by scanning electron microscope (SEM). Statistical analysis was performed by using ANOVA test (P < 0.05). Results: The opalescence values determined for the body porcelain groups with thicknesses of 0.50, 0.75, and 1.00 mm and body/opaque porcelain specimens with thicknesses of 0.45/0.05, 0.70/0.05, and 0.95/0.05 mm were 3.35 ± 0.15, 3.83 ± 0.10, 6.73 ± 0.25, 7.95 ± 0.34, 15.16 ± 0.60, and 16.49 ± 0.89, respectively. The specimens in the body and body/opaque porcelain groups exhibited significant increases in their opalescence values with increasing thickness (P = 0.00). The opalescence values of the specimens increased significantly with the addition of a 0.05 mm opaque porcelain layer (P = 0.00). The opalescence values of the composites containing body/opaque porcelain layers with thicknesses of 0.45/0.05, 0.70/0.05, and 0.95/0.05 mm and luting resin cement were 9.46 ± 0.17, 16.47 ± 0.15, and 18.38 ± 0.47, respectively. The opalescence values of the composite specimens increased significantly with an increase in the thickness of the porcelain layer(P = 0.00). Conclusions: The opaque porcelain layer and opaque resin cement can significantly improve the opalescence properties of porcelain laminate veneers for discolored teeth, but the opalescence performance is still poor than natural teeth. The body porcelain only contributes to opalescence within a certain thickness range. [ABSTRACT FROM AUTHOR]

Background: To evaluate the comprehensive effect of translucency, thickness, cement shades, and background color on the masking ability of resin-matrix ceramic veneer restorations. Methods: Resin-matrix ceramic specimens with 2 translucencies (LT, HT) and 3 thicknesses (0.5, 1.0, and 1.5 mm) were made of Upcera Hyramic (A2 shade). Cement specimens were made of Variolink N in 4 shades (yellow, white, transparent, and bleach XL). Five background specimens were made of IPS Natural Die Material in 5 shades (ND1, ND2, ND3, ND4, and ND5). Color coordinates of 120 subgroups (n = 5) of combined specimens composed of different ceramic, cement, and background specimens were obtained using a spectroradiometer. Color difference (ΔE00) compared with a 4-mm thick specimen of LT and HT ceramics was calculated and four-way ANOVA was used for statistical analysis (α = 0.05). Results: Translucency, thickness, cement shade, background color, and their interaction had significant effects on ΔE00 (p < 0.001). ΔE00 values of HT groups were always higher than that of LT groups and were greater than 1.8 against all background colors. ΔE00 values of LT groups could be achieved to be less than 1.8 with appropriate thickness and cement shade. ΔE00 value decreased with increasing ceramic thickness. The effect of cement shade on ΔE00 had no obvious regularity, but ΔE00 values of bleach XL cement shade group were always lower than other cement shade groups under ND3 and ND5 background color. Conclusions: The masking ability of CAD-CAM resin-matrix ceramics can be simultaneously affected by translucency, thickness, cement shade, and background color. Resin-matrix ceramics with low translucency has a better masking ability than that with high translucency. The masking ability of CAD-CAM resin-matrix ceramics increase with increasing thickness. Cement shade has less impact on the final color of resin-matrix ceramic restorations. [ABSTRACT FROM AUTHOR]

The primary aim of this in vitro study was to compare the load-bearing capacity of lithium disilicate occlusal veneers, fabricated via different manufacturing processes. Secondary objectives included assessing internal accuracy and production time-efficiency. Four fabrication methods for ultra-thin lithium disilicate occlusal veneers on extracted human molars with simulated erosive defects were compared (n = 20/group): CAM: milled lithium disilicate (IPS e.max CAD); HPR: heat-pressed lithium disilicate (IPS e.max Press) out of a milled PMMA template (Ddpmma CAST); 3DP: 3D-printed lithium disilicate (experimental lithium disilicate); PTE: heat-pressed lithium disilicate (IPS e.max Press) out of a 3D-printed template (SilaPrint cast). Internal accuracy was measured prior to thermo-mechanical aging, followed by static loading to measure the load-bearing capacity (F max). Fabrication time (time-efficiency) was also recorded. Statistical analysis was performed using the Kruskal-Wallis (KW) test. No statistically significant differences were found in median load-bearing capacities (F max) between the groups (KW p = 0.5902): CAM 1821 N, HPR 1896 N, 3DP 2003 N, PTE 1687 N. Significant differences were found in internal accuracy between the groups that employed printing processes (3DP, PTE) and all other groups in margins (p < 0.001), cusps (p < 0.0018), and fossae (p < 0.0346). The time-efficiency measurements indicated an increase in fabrication time, starting from CAM 67.2 ± 5.8 min, followed by HPR 200.8 ± 33.0 min, PTE 289.2 ± 38.7 min, and peaking with the highest duration observed for 3DP 701.6 ± 8.1 min. The fabrication method of ultra-thin lithium disilicate occlusal veneers does not significantly impact their load-bearing capacity, but affects the clinical fit and adaptation of the veneers. • All fabrication methods exhibited high load-bearing capacities, with no significant differences between the groups. • Milled or heat-pressed restorations demonstrated minimal marginal discrepancies and high internal accuracy. • 3D-printed restorations showed larger marginal gaps but superior internal accuracy in the cusp and fossa regions. • Direct milling was the most time-efficient; 3D-printing the most time-consuming, and procedures involving methacrylate-based templates were intermediate. [ABSTRACT FROM AUTHOR]

The precision of the luting protocol plays a crucial role in the success and survival rate of porcelain laminate veneers (PLVs). This in vitro study aimed to evaluate the influence of different luting techniques on the positioning of PLVs through a novel, noninvasive, scanning-based technique. A total of 45 ceramic PLVs were milled and cemented on human tooth replicas. Specimens were divided into three groups of 15, each subjected to a different luting protocol: flowable composite (Group A), dual-cure resin cement (Group B), and preheated composite resin (Group C). After luting procedures, specimens were scanned, and every STL file was superimposed with the original tooth design in Geomagic Control X version 2022.1 software to assess linear (incisal, mid, cervical) and angular discrepancies. Statistical analysis was performed using one-way ANOVA, Tukey's HSD tests, and regression analysis. ANOVA results showed no statistically significant differences for incisal (F = 0.327, p = 0.723), mid (F = 0.287, p = 0.752), cervical (F = 0.191, p = 0.827), and angular (F = 0.026, p = 0.975) measurements. Tukey's HSD post hoc tests confirmed the lack of significant pairwise differences between groups. The study demonstrated that the type of luting agent used does not significantly impact the final position of PLVs. This suggests flexibility in the choice of luting agents without compromising the accuracy of PLV placement. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate the feasibility of monolithic zirconia laminate veneers (MZLV) compared to lithium disilicate laminate veneers (LDLV). Materials and methods: Sixty resin replicas, each prepared with depths of 0.5 mm, 0.7 mm, and 1 mm, were produced using a 3D printer from acrylic teeth. Laminate veneers of these thicknesses were milled from pre-sintered monolithic zirconia (3rd generation) and lithium disilicate blocks. The intaglio surface of MZLV was treated with air abrasion using 110 μm diameter silica-modified aluminium oxide particles and ceramic primer, while LDLV was etched with etchant gel and treated with the ceramic primer before cementation with resin cement. Vertical marginal discrepancy (VMD) was assessed using a stereomicroscope, and a load-to-failure test was conducted using a universal testing machine. Failure modes were evaluated macroscopically on fractured surfaces. Data were analysed statistically using Two-way ANOVA and Bonferroni correction (α = 0.05). Results: LDLV samples exhibited significantly larger VMD compared to MZLV samples across all thicknesses, especially in cervical, palatal, and mean data. Within the LDLV group, load-to-fracture values for 0.7 mm and 1.0 mm thicknesses were similar, whereas for 0.5 mm thickness, it was significantly lower. In the MZLV group, load-to-fracture values were lower for 0.7 mm and 1.0 mm thicknesses compared to LDLV, but higher for 0.5 mm thickness. Conclusions: Material choice and restoration thickness significantly influence laminate veneer restorations' success. MZLV generally exhibits superior vertical marginal fit compared to LDLV, with varying load-to-failure values across different thicknesses. Clinical management of debonding in MZLV is simpler compared to restoration fracture in LDLV. Clinical relevance: Considering clinical factors, MZLV may be a preferable option to LDLV for this restoration with the thickness of 0.5 mm. [ABSTRACT FROM AUTHOR]

Purpose: This narrative review aimed to survey the clinical outcomes of laminate veneers (LVs), including their survival and success rates. Study selection: An electronic search of MEDLINE/PubMed, Web of Science, Cochrane Library, and Google Scholar from 2000 to April 2023 was conducted using the keywords "laminate" OR "veneer" OR "porcelain" OR "feldspathic" OR "lithium disilicate" OR "composite resin" OR "zirconia" OR "survival" OR "success." Case reports, case series, reviews, abstracts, in vitro studies, and observational studies were excluded. Five researchers independently evaluated the titles and abstracts of all identified studies. Results: A total of 55 studies were identified. None of the studies met the criteria for zirconia LVs. According to the studies in this review, LVs fabricated with feldspathic porcelain, leucite-reinforced glass ceramics (LRG), and lithium disilicate ceramics (LDS) exhibited satisfactory survival and success rates. Furthermore, hydrofluoric acid etching followed by silane priming of the surface of ceramic LVs is necessary for improved clinical outcomes. The extent of dentin exposure significantly decreases the success rate of ceramic LVs. An appropriate adhesive luting process is required to achieve the long-term success of ceramic LVs. Dentin exposure should be minimized or sealed during tooth preparation to achieve a reliable and durable bond between LVs and abutment teeth. Conclusions: Based on this narrative review of the literature, the use of silica-based ceramic feldspathic porcelain, LRG, and LDS is recommended for LVs. [ABSTRACT FROM AUTHOR]

This study aimed at examining the bond strength between zirconia and ceramic veneer, following the ISO 9693 guidelines. A total of fifty specimens of zirconia/ceramic‐veneer system were produced using two commercial zirconias (VITA YZ‐HTWhite and Zolid HT+ White, referred to as Group A and Group B, respectively) and a ceramic‐veneering material (Zirkonia 750). The microstructure (via x‐ray diffraction analysis, XRD and Secondary Electron mode, SEM) and the mechanical properties (via 3‐point bending tests) of the two groups were assessed. Then, experiments were conducted according to the ISO 9693 and conventional protocols applied for producing zirconia/ceramic‐veneer restorations. Bond strength values, measured by 3‐point bending tests, were 34.42 ± 7.60 MPa for Group A and 31.92 ± 6.95 MPa for Group B. SEM observations of the cohesively fractured surfaces (on the porcelain side) and the examination for normality using the Shapiro–Wilk test suggested the use of Weibull statistical analysis. Median strength (σ50%) for Group A and Group B was 34.76 and 32.22 MPa, while the characteristic strength (σ63.2%) was 35.78 and 33.14 MPa, respectively. The Weibull modulus disparity between groups (12.69 and 13.07) was not significant. Bond strength exceeded the ISO 9693 minimum of 20 MPa, suggesting satisfactory strength for clinical use. [ABSTRACT FROM AUTHOR]

Objective: Demonstrate the ability of 0.5 mm thickness lithium disilicate laminates associated with resin cement to mask different substrate saturations. Methods: 60 specimens (n = 5) were prepared with CAD/CAM lithium disilicate glass–ceramic IPS e.max CAD, 0.5 mm thick, in three degrees of translucency (HT, MT and LT); cemented by Variolink Esthetic LC Light+ (L) and Neutral (N) on composite resin substrates A1 and A4 shades. Color measurements were performed by a spectrophotometer (CM‐3700d ‐Konica Minolta). The L*, a*, b* parameters of the tri‐layer structure (laminate/ resin cement/ substrate) were used to calculate color difference (∆E00) by CIEDE2000 formula and Translucency Parameter (TP00). This study adopted ∆E00 = 0.8, as perceptibility threshold (PT), and ∆E00 = 1.8, as acceptability threshold (AT). Statistical analyses were performed by one‐way ANOVA and Tukey tests (a = 0.05). Results: Color difference between resin cement shades showed statistical differences (p < 0.0001) and ∆E00 > 1.8 for all groups. Color difference between substrates saturations showed a significant statistical difference (p < 0.0001) and ∆E00 values above AT for all groups. The TP00 demonstrated significant statistical differences (p < 0.0001). The LTL combination, the opaquest set, showed the smallest ∆E00 values between substrate shades differences, however, above AT. Conclusion: The translucency of the lithium disilicate, the substrate saturation and the resin cement opacity influenced final color of restoration. The ceramic translucency impact on final color was reduced by opaque resin cement. Furthermore, the LT lithium disilicate and the Light+ resin cement reduced the translucency of the restoration, contributing to mask saturated substrate. Clinical Relevance: This study shows the influence of conservative lithium disilicate laminates with different degrees of translucency associated with resin cement on final color of saturated substrate restorations. A minimally invasive esthetic protocol for masking substrates is demonstrated by associating low translucency ceramic laminates and opaque resin cement. [ABSTRACT FROM AUTHOR]

Dental aesthetics is a significant concern for patients undergoing prosthodontic restorative treatments. Achieving beauty involves specific proportions in the face and teeth, with optimal symmetry, height, and width. Therefore, analysing facial and dental parameters is vital in dentistry. The selection of teeth is crucial for restoring aesthetics. This case report aims to provide an overview of facial and dental aesthetics, including the role of biomaterials in aesthetic restoration. The shape and size of anterior teeth are essential for pleasing dental and facial aesthetics, with harmony often following the golden proportion (GP). According to GP, the visible width of the lateral incisor should be 62% of the central incisor, and the visible width of the canine should be 62% of the lateral incisor. Various restorative biomaterials, such as ceramic/zirconia, composite, PEEK, and indirect resin, are used for anterior aesthetic restoration. Newer ceramic biomaterials and advanced treatment modalities are being developed to achieve superior aesthetic results. Porcelain veneers and dental composite restorations are effective in enhancing the shape and color of teeth, contributing to an improved dental appearance. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this exploratory in vitro study was to compare and evaluate the load-bearing capacity (LBC) of ceramic-veneered zirconia and composite-veneered polyetheretherketone (PEEK) three-unit fixed dental prostheses (FDPs) with and without thermocycling (TC).Materials and Methods: The study included 40 samples of three-unit FDPs replacing mandibular first molars. The four groups included were: ceZIR (feldspathic ceramic-layered zirconia), ceZIR TC (feldspathic ceramic-layered thermocycled zirconia), cPEEK (composite-layered PEEK), and cPEEK TC (composite-layered thermocycled PEEK) (n = 10 per group). All frameworks were CAD/CAM milled. Ten PEEK and 10 zirconia samples were subjected to TC (6,000 cycles). All 40 FDP specimens were loaded by applying static load, using a universal testing machine. The maximum load required to fracture the specimens denoted the LBC. The comparison of LBC between the four groups was done by using two-way ANOVA with Tukey's post-hoc analysis (α = .05).Results: There was no statistically significant difference between LBC of cPEEK and ceZIR (P > .001) without thermal aging. LBC values decreased considerably for thermally aged specimens. Statistically significant differences were observed between LBC of cPEEK TC and ceZIR TC (P < .001), cPEEK TC and cPEEK (P < .001), and ceZIR TC and ceZIR (P = .001). On fracture analysis, cPEEK showed delamination failures whereas ceZIR displayed catastrophic connector fractures.Conclusion: This comparative evaluation offers preliminary data highlighting substantial depreciation in the LBC of layered PEEK under simulated intraoral conditions, thus raising a question regarding the clinical longevity of layered PEEK multi-unit restorations. In contrast, feldspathic-layered zirconia can be suitable for use in posterior FDPs. [ABSTRACT FROM AUTHOR]

Purpose: To assess the shear bond strength of composite resin to poly(etheretherketone) (PEEK) after mechanical and chemical surface treatments. Materials and Methods: A total of 48 PEEK discs were fabricated and divided equally into four surface treatment groups (n = 12 each): (1) airborne-particle abrasion (APA) with 50-µm alumina particles at 2-MPa pressure for 10 seconds; (2) 98% sulfuric acid etching for 1 minute; (3) APA + sulfuric acid etching; and (4) no surface treatment. Specimens were conditioned, and then veneering composite resin was applied to the PEEK surfaces and polymerized. Bond strength was measured using a universal testing machine. One-way analysis of variance and Tukey post hoc test were applied for statistical analysis. Results: The mean shear bond strength values of the sulfuric acid etching group were higher than that of the APA + acid etching, APA, and control groups (P < .05). Mean shear bond strength values for the APA + acid etching samples were higher than for the control and APA groups (P < .05). Conclusion: There was no significant difference between the samples treated with APA and the control group. The bond strength was highest when PEEK was prepared with sulfuric acid etching alone. [ABSTRACT FROM AUTHOR]

Introduction: Structural abnormalities or anomalies in the anterior teeth, also known as the aesthetic zone, are an important problem for patients and a challenge for dentists. Structural abnormalities or tooth anomalies can change in color, shape, and function. Most dentists prefer minimally invasive aesthetic treatment. One of the aesthetic treatment options for anterior teeth is veneers. Veneer is a restoration that covers the labial part of the tooth with a thin layer of material to correct abnormalities in the color, shape, or function of the tooth. Veneer restoration can be done indirectly with porcelain material made in a laboratory and directly with composite material on the tooth surface or prefabricated which is available from the factory. Componeer is a prefabricated composite veneer that combines the aesthetic properties of ceramic veneers and the adhesive ability of composite veneers to the tooth structure. This case report describes the treatment of two central incisors that had been filled with composite and peg shapes on both lateral incisors using a componeer. Case report: A 32-year-old female patient came to the Dental Conservation Clinic at Dentistry Hospital, Padjadjaran University with the main complaint of her right and left upper front teeth and wanted to repair her old fillings and close the gap between her right and left upper front teeth and her canine teeth. Clinical examination showed that teeth 11 and 21 had been filled with composite which had changed color and had an inharmonious shape as well as a gap between the upper front teeth on the right and left sides and the right and left canine teeth. Treatment: The maxilla and mandibular teeth are molded for study models and working models. In the working model, a wax-up is carried out, then a mock-up on the patient's teeth. Next, choose the color and size of the components that match the mock up results. Teeth 11 and 21 had their old composite fillings cleaned and refilled with dentin colored composite, teeth 13, 12, 11, 21, 22, and 23 were prepared with a minimum thickness of 0.3 mm to make room for the componeer material. The teeth was etched and bonded, and bonding was applied to the inner surface of the componeer. The composite is placed on the inner surface of the componeer then placed on the labial surface of the tooth and pressed with a special tool, then light cured. The final step is polishing. Treatment results: Teeth 13, 12, 11, 21, 22, and 23 which had undergone veneer treatment using componeer, were controlled after 1 week of treatment. The patient did not complain about the results of the treatment and said he was satisfied with the treatment. [ABSTRACT FROM AUTHOR]

Objective: Traditional and modern‐day laboratory techniques can be used to mask vital and non‐vital discolored teeth. Clinical Considerations: Two clinical case reports are presented showing different treatment approaches to differing clinical scenarios of partial coverage veneer and full coverage crown restorations, respectively. Conclusions: Feldspathic ceramics should be considered when customization of stump shade correction and equalization is required with minimum facial reduction with veneer restorations. Translucent zirconia (5 mol% Y2O3) can be used to mask metal posts and core restorations on non‐vital teeth using an opaquer material that is infused into the intaglio surface in the green state. Clinical Significance: Different clinical scenarios will present to the clinician in regard to discolored stump shades where understanding what laboratory material treatment options are available that will help guide definitive restoration types and ultimately tooth preparation design. [ABSTRACT FROM AUTHOR]

Objective: To analyze the influence of restoration design (partial‐coverage restoration vs. crown) and ceramic layer thickness on the performance and failure loads of CAD/CAM‐fabricated lithium disilicate (LDS) reconstructions on molars after fatigue. Materials and Methods: Seventy‐two posterior monolithic CAD/CAM‐fabricated LDS restorations (IPS e.max CAD, Ivoclar Vivadent) with different occlusal/buccal ceramic layer thicknesses (1.5/0.8, 1.0/0.6, and 0.5/0.4 mm) and restoration designs (PCR: non‐retentive full‐veneer/partial‐coverage restoration, C: crown,) were investigated and divided into six groups (n = 12, test: PCR‐1.5, PCR‐1.0, PCR‐0.5; control: C‐1.5, C‐1.0, C‐0.5). LDS restorations were adhesively bonded (Variolink Esthetic DC, Ivoclar Vivadent) to dentin‐analogue composite dies (Z100, 3M ESPE). All specimens were subjected to thermomechanical loading (1.2 million cycles, 49 N, 1.6 Hz, 5–55°C) and exposed to single load to failure testing. Failure analysis was performed with light and scanning electron microscopies. Data were statistically analyzed using ANOVA, Tukey‐Test, and t‐test (p < 0.05). Results: Eight crown samples (C‐0.5) and one PCR specimen (PCR‐0.5) revealed cracks after fatigue, resulting in an overall success rate of 87.5% (crowns: 75%, PCRs: 96.88%). Direct comparisons of PCRs versus crowns for thicknesses of 0.5 mm (p < 0.001) and 1.0 mm (p = 0.004) were significant and in favor of PCRs. Minimally invasive PCRs (0.5 and 1.0 mm) outperformed crowns with the identical ceramic thickness. No difference was detected (p = 0.276) between thickness 1.5 mm PCRs and crowns. Conclusions: Minimally invasive monolithic CAD/CAM‐fabricated posterior LDS PCRs (0.5 and 1.0 mm) resulted in superior failure load values compared to minimally invasive crowns. Minimally invasive crowns (0.5 mm) are prone to cracks after fatigue. Clinical Significance: Minimally invasive CAD/CAM‐fabricated LDS PCR restorations with a non‐retentive preparation design should be considered over single crowns for molar rehabilitation. [ABSTRACT FROM AUTHOR]

Objectives: This article presents case reports highlighting over‐treatments with resin composites, often misconceived as minimally invasive procedures. Clinical Considerations: Tooth‐colored restorative materials, such as ceramics and composites, have found widespread application to correct problems related to tooth color, shape, and alignment. When composite resin is used, these procedures can be done in a very conservative, cost‐effective, and timely fashion. However, it is noteworthy that contemporary dental esthetic expectations are based on standards propagated by social media and other marketing and communications platforms. The abuse of and addiction to social media impacts can lead to unrealistic esthetic expectations and standards for both patients and dentists. Conclusions: After a critical discussion on ceramic veneers published in part I of this 2‐part series, this article directs attention towards what has become a trendy fashion, i.e., the use of direct composite resins as "non‐prep" veneers in clinical situations that arguably required no restorative intervention at all. We further explore how social media influences the decision‐making processes of both professionals and patients. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the incidence of ultrathin ceramic veneer fractures with different preparation protocols over a period of 36 months and the possible relationship with local- and patient-related factors. Materials and Methods: Adult patients who received ceramic veneers for improvement in smile esthetics were selected from a private practice pool. Restorations were grouped as conventional (prep) or ultrathin ceramic veneers following either a minimal preparation (min-prep) or no tooth preparation (no-prep) protocol. After veneer bonding, all patients were followed up at intervals of 6 months up to 36 months. A panel of clinical outcomes was recorded, and patient satisfaction was assessed at 36 months. Results: The study sample was formed by 49 patients who received a total of 194 veneers. Twelve veneers were prep, 125 were min-prep, and 57 were no-prep. Total fracture occurrence was 9.8% in 13 participants. No fractures were observed in prep veneers, while 16 out of 125 min-prep and 3 out of 57 no-prep veneers had fractures. Most fractures (13 out of 19) occurred early, within the first 12 months after bonding. Out of 194 veneers, only 1 had a catastrophic failure (0.5%), 3 had large (≥ 1 mm) chippings (1.5%), and 15 had minor (< 1 mm) chippings (7.7%). A generalized estimating equation model revealed that the odds of veneer fracture were significantly higher in men (odds ratio [OR] = 11.29), in patients who exhibited tooth wear at baseline (OR = 5.54), and in central (OR = 13.56) and lateral (OR = 10.43) incisors compared to canines and premolars. All participants indicated that they would not change to a different restorative protocol in order to have a thicker restoration and possibly less risk of fracture. Conclusion: Ultrathin ceramic veneers are a viable cosmetic dentistry treatment option that involve minimal or no tooth preparation. However, a tendency for increased early fractures was observed in the min-prep group. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the impact of different extents of misfit between a restoration and the supporting implant on veneer fractures in screw-retained implant-supported metal-ceramic fixed dental prostheses (FDPs).Materials and Methods: A finite element analysis (FEA) model of a five-unit screw-retained metal-ceramic FDP supported by three implants was constructed, replicating a previous in vitro study. Eight different gap configurations at the single terminal implant, ranging from 0 to 150 μm, were tested. All setups were tested after clamping and with a load of 200 N applied. Maximum stress within the FDP was calculated.Results: The stress increased with each increase in misfit size above 30 μm, with the relationship between gap size and stress being linear up to 100-μm misfit. Above 100 μm, the stress increase accelerated. The stress pattern within the FDP changed with increasing gap size, confirming the findings of a previously conducted in vitro experiment for a misfit of 150 μm.Conclusion: The results of the FEA were in agreement with in vitro observations, validating the predictive value of FEA for technical complications. A misfit between an FDP and a supporting implant implies an increased risk of veneer fracture. Above a misfit of 30 μm, the stress levels are likely to be high enough to cause veneer fracture, and the risk increases disproportionately for misfit above 100 μm. [ABSTRACT FROM AUTHOR]

This article provides an overview of the available evidence on the performance, with particular consideration of the longevity of restorative materials used in the management of tooth wear. Different materials can be employed depending on whether a subtractive or additive strategy is used. Preference should be given to the latter to help preserve remaining tooth tissue. The use of both direct and indirect materials may yield acceptable survival results when considering data with at least 5 years of follow-up. Patients should be informed that because tooth wear is a continuous process, a certain level of maintenance of the restorations will be necessary and that this may impact on the success of the treatment. CPD/Clinical Relevance: Conservative, adhesive strategies are suitable for the restorative management of tooth wear [ABSTRACT FROM AUTHOR]

Objective: To evaluate clinical outcome of maxillary midline diastema closure using sectional feldspathic porcelain veneers up to 4 years. Materials and Methods: Five female patients with stable maxillary midline diastema were included in the current study and restored with minimal invasive sectional feldspathic porcelain veneers under dental microscope. Esthetic, functional, as well as biologic properties of sectional veneers were evaluated according to the World Dental Federation (FDI) criteria after 1 to 4 years' follow‐up. Results: Based on FDI criteria, all five cases were evaluated as clinically excellent to satisfactory during a mean observation period of 26.4 months. Slight to moderate cervical marginal staining was observed in two cases after 3 to 4 years' follow‐up. Slight white line or ditching of labial surface margin was found in most cases, but it is not easy to be noticed with saliva covering the margins. Conclusions: Sectional feldspathic porcelain veneers presented satisfying clinical outcome with potential long‐term esthetic risk for maxillary midline diastema closure. Clinical Significance: 1. Sectional feldspathic porcelain veneers presented satisfying short to medium term clinical performance when applied to close maxillary midline diastema. 2. The exposure of labial surface margin may increase a long‐term potential esthetic risk. [ABSTRACT FROM AUTHOR]

Purpose: To investigate whether high-level irradiance and short light exposure times with light-emitting diode (LED) curing units could provide bond strength comparable to halogen lights for ceramic laminate veneers (CLVs).Materials and Methods: A total of 160 extracted human maxillary central incisors were prepared to receive CLVs (lithium disilicate) in shades A1 and A3.5. CLVs were luted with light-curing (LC) and dual-curing (DC) resin cements using four protocols: 3 seconds in extra power mode, 8 seconds in high power mode, or 10 seconds in standard mode with an LED unit, or 40 seconds with a conventional halogen light from all aspects (n = 10). Following thermal cycles, shear bond strength test was performed with a universal testing machine. Data were analyzed using one-way analysis of variance and post hoc Tukey test. Failure modes were classified under a stereomicroscope, and data were analyzed using Pearson chi-square test (P = .050).Results: According to the intragroup comparison of different irradiation protocols, the mean shear bond strength of the A1-LC-10 group was found to be significantly higher than that of the A1-LChalogen group (P = .026). Shear bond strength values of the A1-LC-10 group and A3.5-LC-10 group were significantly higher than that of the A3.5-DC-10 group (P = .003). The A3.5-DC-3, A3.5-LC-3, and A1-DC-8 groups revealed the significantly most adhesive failures, and the A1-LC-8 group revealed the most mixed failures (P < .001).Conclusion: Both light and dark ceramic shades with LC cement combination responded the best to the standard mode of 10-second exposure time with LED application. However, with conventional halogen light application, the highest bond strength values were obtained with DC cement and light ceramic shade combination. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the impact of different veneering techniques on the fracture load of telescopic secondary crowns made of a high-performance polymer (Ultaire aryl ketone polymer [UAKP]).Materials and Methods: Zirconia primary crown models (taper of 0 degrees) were prepared (N = 48), polished, scanned, and divided into four veneering groups (n = 12 each): premanufactured, digital, full anatomical, and vestibular. For all groups except vestibular, a standardized telescopic secondary crown (thickness: 0.6 mm, circular margin: 1 mm) was constructed, adapted to the corresponding primary crown, milled from UAKP, and veneered. The veneered master crown was developed based on the premanufactured group. After surface polishing, all specimens were artificially aged in a chewing simulator (1.2 million cycles, 50 N, 1.1 Hz, between 5°C and 55°C). Fracture load was tested in a universal testing machine with a piston (Ø = 6 mm, 1 mm/minute). Fracture patterns were analyzed. For statistical analysis, Kolmogorov-Smirnov test and descriptive statistics followed by one-way ANOVA with post hoc Scheffé test were conducted (P < .05).Results: Significant differences in fracture load were found between different veneering techniques (P < .001), with the highest values for the vestibular and digital groups, followed by the premanufactured group. Full anatomical veneering showed the significantly lowest fracture load (1,885 ± 397 N). For all specimens, cohesive brittle fractures with similar fracture patterns occurred, irrespective of the veneering technique.Conclusion: The veneering technique of telescopic secondary crowns made of high-performance polymer affects overall stability. All veneering techniques provided sufficient fracture load values for telescopic secondary crowns made of UAKP. Digital veneers seem the most recommendable. [ABSTRACT FROM AUTHOR]

Objective: This article describes a technique to implement guided tooth preparation where the tooth is virtually prepared in the laboratory and preparation templates are created for chairside use. Clinical Considerations: Prior to any tooth preparation, patient records are acquired with an intra‐oral scanner, both stump and final shades are selected, and digital photos are taken. These digital records are used in combination with digital laboratory tools to do the virtual preparation first, and then to provide chairside templates for guided tooth preparation. Conclusions: The traditional approach of tooth preparation has evolved from historically preparing a tooth without any pretreatment guidance to, more currently, preparing the tooth through a mock‐up of the desired final restoration. The outcome of these traditional approaches is highly dependent on the operator's skills to produce a successful outcome, and often resulted in more tooth structure removal than necessary. However, CAD/CAM technology now offers a guided tooth approach to tooth preparation which minimizes tooth structure removal and provides an advantage to the beginner dentist. Clinical Significance: This is a unique approach in digital restorative dentistry. [ABSTRACT FROM AUTHOR]

Dental zirconia has been commonly used for all ceramic restorations as it has excellent mechanical properties and adequate optical properties. Dental zirconia has crystalline structure and transformation toughening mechanism which makes it one of the strongest dental ceramics available. Despite its high strength, fracture of restoration still occurs when dental zirconia is used. Multiple factors can influence zirconia's mechanical properties. This present narrative review is focused on the procedures that may have influence on zirconia's mechanical properties. The clinical procedures include chairside grinding, surface treatment and the use of dental adhesive. All these factors may influence microstructural changes and phase transformation which, eventually, affect strength of zirconia. [ABSTRACT FROM AUTHOR]

Copyright of RSBO: Revista Sul-Brasileira de Odontologia is the property of UNIVILLE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and Objective: This study aimed to compare the surface finish of milled leucite-reinforced ceramics polished with ceramic and composite polishing systems based on the manufacturers' recommendations. Materials and Methods: Sixty subtractive computer-aided manufactured (s-CAM) leucite-reinforced glass-ceramic specimens (IPS-Empress-CAD) were assigned into six groups: no polishing, a ceramic polishing kit, and four composite kit groups. The roughness average (Ra) was evaluated in microns using a profilometer, and scanning electron micrographs were obtained for qualitative analysis. A Tukey HSD posthoc test (α = 0.05) was used to determine significant intergroup differences. Results: After surface evaluation of the ceramics, the Ra values of the polishing systems ranked OptraFine (0.41 ± 0.26) < Enhance (1.60 ± 0.54) < Shofu (2.14 ± 0.44) < Astropol (4.05 ± 0.72) < DiaComp (5.66 ± 0.62) < No Polishing (5.66 ± 0.74). Discussion: Composite polishing systems did not provide as smooth surfaces as the ceramic polishing kit for CAD-CAM leucite-reinforced ceramics. Thus, using ceramic polishing systems, polishing leucite ceramics is recommended, whereas composite polishing systems should not be considered as an alternative for use in minimally invasive dentistry. [ABSTRACT FROM AUTHOR]

Objective: the use of digital tools in dentistry offers a new perspective for daily clinical activities. Digital information is a starting point for a wax-up and intraoral matrix, which is widely reported in the literature as an objective and efficient communication tool between dentist, patient, and technician. This case report demonstrates digital aesthetic planning for correcting anterior maxillary diastemas with lithium disilicate dental veneers. Method: patient JD, female, 22 years old, attended the clinic, complaining of diastemas of the maxillary anterior teeth. The patient reported she had had several direct composite resin restorations performed but was still frustrated with her smile. After the clinical and photographic examinations and obtaining the study models, digital planning was conducted, and a new model was printed. In this technique, a silicone matrix was placed on the model to guide the buccal and incisal preparation. After making the preparations, molding, and choosing the color, a mock-up with bisacrylic resin was made to facilitate the patient to see the result. Lithium disilicate dental veneers were cemented with light-cured resin cement. Result: the treatment showed a satisfactory aesthetic result, meeting the patient's expectations. Conclusion: the combination of digital planning and mock-up for diagnosis and treatment planning presents predictable and highly satisfactory results in the aesthetic rehabilitation of the anterior teeth. [ABSTRACT FROM AUTHOR]

Introduction: Peg teeth are incisors which mesio-distal incisal widths are smaller than the cervical widths. The significant reduced size and format of those teeth are often related to a distal migration of the maxillary central incisors and maxillary anterior diastema. The presence of bilateral canine guidance is recommended to obtain a balanced occlusion, as it promotes a single contact between the maxillary and mandibular canines on the working side, with no other horizontal contacts. In aesthetic reconstructions, dental ceramics present high resistance and optical properties that resemble natural teeth. Objective: The aim of this study is to report an aesthetic and functional rehabilitation of peg teeth and establishment of canine guidance with ceramic fragments and veneers. Case report: The 25-year-old female patient complained about her "sharp" teeth. Clinical examination revealed the presence of peg-shaped maxillary lateral incisors, diastema between maxillary central incisors, and absence of canine guidance. After patients digital smile design and in-office tooth bleaching, a study cast and diagnostic wax-up were obtained. Following mock-up and patients approval, dental preparations and impressions were performed. Lithium disilicate ceramics were fabricated and tried in mouth. Veneers were then bonded, followed by occlusal adjustments, finishing and polishing. Conclusion: Thus, the final result was a natural smile, integrating aesthetics and function after 1-year follow-up. [ABSTRACT FROM AUTHOR]

An esthetically pleasing smile is a valuable aspect of physical appearance and plays a significant role in social interaction. Achieving the perfect balance between extraoral and intraoral tissues is essential for a harmonious and attractive smile. However, certain intraoral deficiencies, such as non-carious cervical lesions and gingival recession, can severely compromise the overall aesthetics, particularly in the anterior zone. Addressing such conditions requires careful planning and meticulous execution of both surgical and restorative procedures. This interdisciplinary clinical report presents a complex case of a patient with esthetic complaints related to asymmetric anterior gingival architecture and severely discolored and eroded maxillary anterior teeth. The patient was treated using a combination of minimally invasive ceramic veneers and plastic mucogingival surgery, resulting in a successful outcome. The report emphasizes the potential of this approach in achieving optimal esthetic results in challenging cases, highlighting the importance of an interdisciplinary team approach in achieving a harmonious balance between dental and soft tissue aesthetics. [ABSTRACT FROM AUTHOR]

This study intended to evaluate the effect of digital veneering on four‐point flexural strength (FS) and microtensile bond strength (μTBS) of veneered zirconia. Two different zirconia blocks, a lithium disilicate and a feldspathic ceramic block, and two different layering ceramics were used. IPS e.max Zir CAD (ZC) and Vita In‐Ceram YZ (YZ) with yttria stabilized tetragonal zirconia polycrystals (3Y‐TZP) were used as substructures. IPS e.max CAD (LD), Vita Mark II (VMII), IPS e.max Ceram (EC) and Vita VM9 (VM9) were used for veneering. Resin cement and fusion ceramic were placed between veneer and zirconia substructure for digital veneering. A total of one hundred and fifty specimens in five groups (n = 30) were prepared for FS and tested in universal machine at 1.0 mm/min. One hundred specimens in five groups (n = 20) were obtained for the μTBS and tested at 1.0 mm/min. Statistical analysis was made by one way ANOVA and Tukey HSD. Conventional veneering showed statistically significant FS. ZC veneered with EC had the highest mean FS and the lowest was obtained in groups veneered through resin cement. YZ layered with VM9 had the highest mean μTBS. ZC veneered through fusion ceramic and YZ veneered through resin cement showed significantly lower and similar μTBS. [ABSTRACT FROM AUTHOR]

Tooth reduction guides allow clinicians to obtain the ideal space required for ceramic restorations. This case report describes a novel design (CAD) for an additive computer-aided manufactured (a-CAM) tooth reduction guide with channels that permitted access for the preparation and evaluation of the reduction with the same guide. The guide features innovative vertical and horizontal channels that permit comprehensive access for preparation and evaluation of the reduction with a periodontal probe, ensuring uniform tooth reduction and avoiding overpreparation. This approach was successfully applied to a female patient with non-carious lesions and white spot lesions, resulting in minimally invasive tooth preparations and hand-crafted laminate veneer restorations that met the patient's aesthetic demands while preserving tooth structure. Compared to traditional silicone reduction guides, this novel design offers greater flexibility, enabling clinicians to evaluate tooth reduction in all directions and providing a more comprehensive assessment. Overall, this 3D printed tooth reduction guide represents a significant advancement in dental restoration technology, offering clinicians a useful tool for achieving optimal outcomes with minimal tooth reduction. Future work is warranted to compare tooth reductions and preparation time for this guide to other 3D printed guides. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the need for photoactivation of the adhesive system inside ceramic laminates before the luting procedure and to evaluate the color stability, nanohardness, and elastic modulus of the adhesive interface activated with singlewave and polywave light-curing units.Materials and Methods: A total of 44 lithium disilicate ceramic veneers (7.0 mm × 8.0 mm × 0.6 mm) were fabricated, bonded to enamel, and sorted into four experimental groups (n = 11 each) according to the type of light-curing unit (Radii-Cal [singlewave] or Valo [polywave]) and mode of adhesive system activation (with or without previous photoactivation). Two luting agents were used: the Tetric N-Bond adhesive system and Variolink Veneer resin cement. A visible ultraviolet spectrophotometer was used to evaluate the color stability before and after UVB artificial accelerated aging for 252, 504, and 756 hours (n = 8 samples from each group). A nanohardness tester under a load of 1,000 μN was used to evaluate the nanohardness and elastic modulus (n = 3 samples from each group). Data regarding the color stability and the mechanical properties (nanohardness and elastic modulus) were subjected to analysis of variance and Tukey protected least significant difference test (α = .05).Results: Prior activation of the adhesive system, the distinct light-curing units, and different aging periods exerted no significant difference on the color stability or mechanical properties of the resin cement (P > .05), except for in the group activated with Radii-Cal after 756 hours, in which the nonprevious activation showed lower color alteration compared to the previous photoactivation (P = .0285). Without prior activation of the adhesive with Valo, the polywave unit promoted higher nanohardness and elastic modulus values in the adhesive system (P < .05).Conclusion: In general, singlewave and polywave light-curing units promoted no difference in color stability or the mechanical properties of the adhesive interface. The prior curing of an adhesive system inside ceramic laminate is not necessary. [ABSTRACT FROM AUTHOR]

Proper gingival displacement is an important prerequisite to obtain good quality impressions. Retraction pastes could eliminate the need for retraction cords, as they have advantages such as comfort reported by patients, faster technique, ease of use, no need for anesthesia, and reduced tissue trauma. The objective of this paper was to present a clinical case of ceramic veneers and crowns in which a retraction paste was used for gingival displacement during both the impression and cementation stages, with 3 years of follow-up. Treatment planning consisted of the replacement of preexisting crowns and ceramic veneers on the anterior teeth. After finishing the preparations, gingival displacement with Astringent Retraction Paste was performed without anesthesia or the use of cords and the impression was taken. Before cementation of the crowns and veneers, the Astringent Retraction Paste was applied. Avoiding the use of cords during cementation prevented trauma. The soft tissue margins remained stable and healthy after a period of 3 years. It can be concluded that retraction pastes could be indicated for displacement of soft tissue when preparation margins are at the gingival level or slightly intrasulcular prior to impressions, restoration cementations, direct restorations, and before relining provisional restorations. Clinical significance: The impression appointment can be traumatic to some patients. The use of cords for gingival displacement usually requires local anesthesia and is time consuming. Retraction astringent pastes instead of cords seems to be a good option for some cases in gingival tissue displacement. [ABSTRACT FROM AUTHOR]

Objective: This study investigated the effect of framework design and modification of porcelain firing cycle on the occurrence of fractures of metal-ceramic and bilayered zirconia crowns after cyclic loading. Method and materials: Twentyfour zirconia crowns with two different apicocoronal incisal veneering porcelain lengths (ZS = 2.0 mm and ZL = 4.0 mm) were fabricated. Twenty-four metal-ceramic crowns with the same apicocoronal incisal veneering porcelain lengths (MS = 2.0 mm and ML = 4.0 mm) served as the control. All the specimens (n = 48) were thermally and mechanically cycle-loaded (49 N) for 1,200,000 cycles, and then evaluated for cracks and/or bulk fractures with an optical stereomicroscope (×10). In the second part of the study, the influence of firing cycle modification on the success rate of twenty-four bilayered zirconia crowns was also evaluated. Finally, two specimens from each group (n = 12) were sectioned and analyzed using a scanning electron microscope. Load-to-failure of the specimen that did not present bulk fracture was further assessed using a universal testing machine. Statistical analysis was performed with Fisher exact test and Kruskal-Wallis test. Results: A statistically significant lower occurrence of fractures (P < .05) was found after cyclic loading for bilayered zirconia versus metal-ceramic crowns. Modification of the firing cycle did not significantly influence the outcome after cyclic loading for zirconia bilayered crowns (P > .05). Conclusion: Within the limitations of this study, porcelain-firing cycle with an extended cooling time did not appear to influence the occurrence of cracks and fractures of bilayered zirconia crowns. [ABSTRACT FROM AUTHOR]

Digital light processing (DLP) 3D printing technology was applied to manufacture thin dental porcelain veneers. The prepared thin dental porcelain veneers showed excellent translucency and appearance. The median and mean particle sizes of the printed glass powders were 10.11 µm and 12.03 µm, respectively, with a unimodal distribution. The green glass compacts were printed layer by layer, with an individual layer thickness of 50 µm. The results showed that, according to the thermal expansion coefficient (TEC) and the thermogravimetry/differential scanning calorimetry (TG/DSC), the debinding procedure of the green glass compacts was annealed at 320 °C for 120 min and 570 °C for 120 min, respectively. The results of the classical sintering kinetics models and SEM examination demonstrated that the glass compacts were sintered at 790 °C for 5 min. The flexural strength and the chemical solubility of the sintered glasses were 132.58 ± 25.83 MPa and 18 μg·cm−2, respectively. Both flexural strength and chemical solubility met ISO 6872 criteria. [ABSTRACT FROM AUTHOR]

Minimally invasive dentistry is a considered process that requires the clinician to be prepared with the ideal sequence and the tools needed. This report describes a well-planned ultraconservative approach using only two ceramic laminate veneers for the maxillary central incisors to significantly improve the patient's overall smile. A 30-year-old female presented with the chief complaints of having diastemas between the central and lateral incisors as well as incisal wear. Diagnostic wax-up and mock-up were performed, and the patient approved the minimally invasive treatment with veneers only for central incisors. A reduction guide aided the conservative tooth preparations, and hand-crafted feldspathic veneers were bonded under total isolation with a rubber dam. The two final conservative veneers significantly improved the smile and fulfilled the patient's expectations. Following proper planning and sequencing, predictable outcomes were obtained and fulfilled the patient's esthetic demands. Minimally invasive restorative dentistry with only two single veneers can impact the entire smile frame. Overtreatment in the esthetic zone is unnecessary to meet a patient's esthetic expectations. [ABSTRACT FROM AUTHOR]

Objectives: To present an update on the concept of cantilevered single‐retainer all‐ceramic resin‐bonded fixed dental prostheses (RBFDPs) first presented 25 years ago in the Journal of Esthetic Dentistry. Overview: The initially presented case of the concept was followed clinically over 26 years and is presented along with two additional clinical long‐term cases using varying methods to obtain an esthetic and hygienic ovate pontic design. Veneered alumina and zirconia ceramic (3 mol% yttria–tetragonal zirconia polycrystalline ceramic; 3Y‐TZP) was used and bonded with a phosphate monomer containing luting resin after 50 μm alumina particle air‐abrasion at 0.25 MPa pressure. The restorations replacing incisors did not debond and soft tissues in the pontic area were maintained over 26 years. Conclusions: Cantilevered single‐retainer all‐ceramic RBFDPs today made from veneered 3Y‐TZP zirconia ceramic can be considered a standard of care for the replacement of single incisors and provide an excellent esthetic outcome with a long‐term preservation of soft tissues in the pontic area. Clinical Significance: Bonding nonretentive oxides ceramics such as alumina and zirconia ceramic with phosphate monomer containing luting resins after alumina particle air‐abrasion is durable over decades. This proves that bonding to zirconia ceramic is not of any problem when adequate methods are used. Single‐retainer zirconia ceramic RBFDPs maintain soft tissues in the edentulous area of single missing incisors and often deem implants unessential for this indication. [ABSTRACT FROM AUTHOR]

Aim: An aesthetic smile is usually associated with healthy appearance and success in many areas of life. Currently, individuals access the internet and social media in search of health information. The aim of this study was to analyse the quality and reliability of information in videos available on the YouTubeTM platform about ultra-thin ceramic laminates. Methods: YouTubeTM was searched using the therms "dental ceramic laminates" and "dental contact lens" for videos uploaded on ultra-thin ceramic laminates. The first 100 videos in Portuguese were selected and rated for quality and reliability. The content and source of videos were also noted. The quality of the videos was determined by evaluating the presence or absence of reliable information and distributed into seven domains. To compare the distributions of quantitative variables between the classifications of source, content, and quality, the Kruskal-Wallis and Dunn's post-hoc tests were performed. Results: Seventy-two videos were included for qualitative analysis. Regarding quality rating, most videos were rated with poor quality. The reliability of the evaluated videos was low. Conclusion: YouTubeTM showed a large number of videos with many views on the topic, but it does not contribute with good quality and reliable information to the population. [ABSTRACT FROM AUTHOR]

Copyright of RSBO: Revista Sul-Brasileira de Odontologia is the property of UNIVILLE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The success of a restorative treatment in anterior teeth for a patient who lost dental aesthetic depends on the esthetic integration between soft tissues and hard tissues with less invasive procedure. (1/2) The present available case report describes the esthetic management of gummy smile, fractured incisor teeth and midline diastema with a multidisciplinary approach of different specialties from diagnosis to treatment planning. Ceramic veneers and crowns yielded a good aesthetic and functional outcome. [ABSTRACT FROM AUTHOR]