Abstract: This study investigates the color correspondence of resin cements and try-in pastes, and the color stability of bonded lithium disilicate ceramic disks. Resin composite disks were fabricated (n = 36) to serve as the background for lithium disilicate disks prepared in two thicknesses (0.5 and 1.0 mm, n = 18 each). Two brands were used for try-in and cement procedures: Variolink Veneer and AllCem Veneer. For baseline, water was applied between the ceramic disks and their respective backgrounds to achieve the control group. This set was subjected to color measurement using an intraoral measurement device (T0). The try-in was inserted between background and ceramic, and this set was subjected to color measurement (T1). After adhesive procedures, the ceramic disk was placed under cement, and color measurement was performed with uncured cement (T2) and 24 h after light-curing (T3). Each set was immersed in distilled water and thermal-cycled, with color measurement being performed after 10,000 (T4) and 20,000 (T5) cycles. Color differences were calculated by CIELab (rEab) and CIEDE2000 (rE00). Data were analyzed by two-way ANOVA for repeated measurements and Tukey's test (α=5%). There was color correspondence of try-in and resin cement for the Variolink system, regardless of the ceramic thickness (p > 0.05). For the AllCem system, the thickness significantly influenced the color measurement (p < 0.001). The Variolink system also demonstrated color stability after 20,000 thermal cycles with rEab < 3.46 and rE00 < 2.25. It was concluded that the color correspondence between a try-in and its respective cement may vary according to resin cement composition.

AIM: To evaluate the leakage on Er,Cr:YSGG laser- and bur- prepared Class V cavities restored with a silorane-based composite resin using different insertion techniques METHODS: 40 cavities were outlined according to: the type of instrument [Er,Cr:YSGG laser (3.0 W power, energy per pulse of 150 mJ, fluence of 53.57J/cm², pulse duration of 140-200 ∝s, 20 Hz repetition rate and 55/65% air/water spray) or diamond bur]; and the type of filling technique (bulk increment or incremental). Four experimental groups were obtained (n=10): G1- diamond bur (DB) and incremental (I); G2- DB and bulk increment (BI); G3- Er,Cr:YSGG and I; and G4- Er,Cr:YSGG and BI. Specimens were restored with a silorane-based composite resin (Filtek P90, 3M/ESPE), subjected to 500 thermal cycles, sealed, infiltrated with 2% (w/v) methylene blue and sectioned in halves. Specimen analysis was scored based on a scale. Statistical analyses were done using the Kruskal-Wallis and Student Newman-Keuls tests (α=0.05). RESULTS: Statistically significant differences were observed between G2 and G4 (p=0.003) and between G1 and G2 (p=0.028). The filling technique did not influence the pattern of dye leakage in the cavity walls (p=0.151). CONCLUSIONS: Less leakage was observed when Er,Cr:YSGG cavities were restored with silorane-based composite resin, using the bulk increment technique. Nevertheless, cavities done using diamond bur have less leakage only when incrementally restored.