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The objective of this study was to assess the influence of immediate dentin sealing (IDS) on the fatigue behavior of laminate occlusal veneers fabricated with CAD/CAM lithium disilicate ceramic and resin composite. Forty sound human molars were prepared and randomly divided into 4 groups (n = 10): RC–IDS+ (IDS and resin composite occlusal laminate veneer); RC–IDS- (resin composite occlusal laminate veneer without IDS); LD–IDS+ (IDS and lithium disilicate laminate veneer); LD–IDS- (lithium disilicate occlusal laminate veneer without IDS). The restorations were obtained using a digital workflow. After surface conditioning and bonding, thermocycling and accelerated fatigue tests (20 Hz, 5000 cycles with an initial load of 300 N, step-size of 100 N for 10,000 cycles, up to 1000 N, and then a step-size of 50 N until failure) were conducted. Fatigue data were recorded for both outcomes (crack or fracture) and statistically analyzed. Fractographic and adhesive interface analysis were conducted. The indirect resin composite groups showed better fatigue behavior compared to lithium disilicate. IDS only had a positive effect for the survival of resin composite restorations for the 'fracture' outcome. Evident presence of micro-gaps at the adhesive interface in the LD–IDS- group could be noted. Immediate dentin sealing improved fatigue resistance behavior of resin composite occlusal veneers. However, this effect was not observed in lithium disilicate veneers. • Occlusal veneers of CAD/CAM resin composite perform better under fatigue than ceramic veneers. • IDS positively influences the fatigue behavior of resin composite occlusal laminate veneers. • IDS promotes a more homogeneous adhesive interface between the agent and dentin/restorative material. • Micro-gaps were visualized at the adhesive interface to dentin in the absence of IDS for LD restorations. [ABSTRACT FROM AUTHOR]

In this prospective clinical trial the survival, success rate and patient satisfaction of ceramic laminate veneers with special interest on existing restorations, immediate dentin sealing and endodontically treated teeth was evaluated. A total of 104 patients (mean age: 42.1 years old) received 384 feldspathic ceramic laminate veneers on maxillary anterior teeth. Veneer preparations with incisal overlap were performed using a mock up technique. Existing resin composite restorations of acceptable quality were not removed but conditioned using silica coating and silanization. Immediate dentin sealing (IDS) was applied when more than 50% of dentin was exposed during preparation. Endodontically treated teeth were not excluded. After adhesive cementation, restorations were evaluated by calibrated evaluators at baseline and final follow-up using modified USPHS criteria. 225 Laminate veneers were bonded onto teeth without existing restorations, 159 on teeth with pre-existing resin composite restorations, 87 to teeth with more than 50% of exposed dentin surface and 43 to endodontically-treated teeth. In total, 19 failures were observed in form of debonding (n = 3), fracture (n = 15) and extraction due to endodontic complications (n = 1). In teeth with more than 50% of dentin exposure, a significant increase in survival rate was observed when IDS was used (96.4% versus 81.8%). No significant difference was found between teeth with and without pre-existing composite resin restorations (84.6% versus 95.5%) or between vital and non-vital teeth (95.6% versus 88.1%). Laminate veneers luted to endontically-treated teeth had a significant mis-match in color compared to vital teeth. Patients who smoked presented with significantly more marginal discoloration, but no intervention was needed. Patients scored favorably values on the Oral Health Impact Profile questionnaire and were generally satisfied with the treatment. In this clinical trial, the ceramic laminate veneers had a relatively high survival rate. Teeth with more than 50% of dentin exposure significantly benefit from IDS. Pre-existing restorations or endodontic treatments do not have an effect on the survival rate of ceramic laminate veneers. However, smoking habits and previous endodontic treatments negatively affect the success rate due to color changes. Clinical Trial Registration Number: NCT03645551 [ABSTRACT FROM AUTHOR]

Objectives Adhesion on dentin is less reliable than on enamel, which could affect the durability of laminate veneers (LV). Immediate dentin sealing (IDS) is suggested instead of delayed dentin sealing (DDS) to overcome hypersensitivity and prevent debonding from dentin. This study evaluated the effect of IDS and DDS on the durability of Li 2 Si 2 O 5 laminate veneers in vitro. Methods Window preparations were made on the labial surfaces of sound maxillary central incisors ( N = 50). They were randomly divided into five groups: Group 1: Enamel only + H 3 PO 4 + Adhesive (control); Group 2: <1/4 dentin + H 3 PO 4 + DDS (2 weeks later); Group 3: Complete dentin + H 3 PO 4 + DDS (2 weeks later); Group 4: <1/4 dentin + H 3 PO 4 + IDS; Group 5: Complete dentin + H 3 PO 4 + IDS. Li 2 Si 2 O 5 laminate veneers (e.max Press) were bonded to the labial surfaces of the teeth with adhesive resin cement (Variolink Veneer). IDS layers were silicacoated (CoJet System) and silanized (ESPE-Sil). The teeth with their bonded laminates were thermocycled (10.000× cycles) and then subjected to static loading (1 mm/min). Failure type and location after debonding were classified. Data were analyzed using ANOVA and Tukey's post hoc test ( α = 0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale ( m ) and shape ( 0 ), values were calculated. Results Mean fracture strength ( N ) per group in descending order was as follows: Group 5 (576 ± 254), Group 4 (478 ± 216), Group 1 (473 ± 159), Group 2 (465 ± 186), and Group 3 (314 ± 137). The presence of complete dentin exposure sealed with DDS after 2 weeks on the bonded surface (Group 3) resulted in significantly lower fracture strength results than those in group 5 with IDS ( p = 0.034). Weibull distribution presented higher shape ( 0 ) for Group 1 (3.67), than those of other groups (2.51–2.89). Failure types were predominantly adhesive failure between the cement and the laminate veneer in Groups 1, 2, 4 whereas Group 3 presented more often complete adhesive failures between the cement and dentin. In Group 5, failures showed some IDS and cement with or without ceramic fracture attached on the tooth. Significance When laminate veneers are bonded to a large dentin substrate, application of immediate dentin sealing improves adhesion and thereby, the fracture strength of Li 2 Si 2 O 5 laminate veneers. [ABSTRACT FROM AUTHOR]