PURPOSE To investigate the effect of resin cement color on the post-cementation shade of thin laminate veneers milled from multilayered glass ceramic blocks for each layer. MATERIALS AND METHODS Thin slices (N = 180) with two thicknesses (A: 8 × 8×0.55 mm and B: 8×8×0.8 mm; n = 90/group) were obtained from multilayered glass ceramic blocks using a diamond saw. Resin die specimens were prepared (8 × 8 × 4 mm) (n = 180) and divided into two resin cement colors (D: -3. L: +3) and one control group (C: translucent). Each slice was luted to the composite specimens using a dual-curing resin cement under a constant load of 250 g and light-polymerized for 120 seconds. Specimens were placed on a white background and CIELab values for each layer of the blank slices (incisal [In], body [Bo], and cervical [Ce]) were recorded using a dental contact spectrophotometer. The values were calculated as ΔE, and the data were statistically analyzed (one-way ANOVA, Shapiro-Wilk). RESULTS Mean ΔE values for A and B were significant (p < 0.05) for In (A: 6.2 ± 1.1; B: 6.6 ± 1.2), Bo (A: 5.1 ± 2.6; B: 3.9 ± 1), and Ce (A: 5.3 ± 2.7; B: 3.8 ± 1.2). Mean ΔE values for In for D and L for A and B groups were significantly higher (6.3 ± 1.2; 6.6 ± 1.2) than Bo and Ce for D (4.4 ± 2.4; 4.6 ± 2.6) and L (4.6 ± 1.4; 4.5 ± 1.7) groups (p < 0.05), respectively. Mean differences between Bo and Ce for A and B groups were insignificant (p 0.05), while for In the differences were significant. Mean differences between Bo and Ce for A (5.1 ± 2.6; 5.3 ± 2.7) and for B (3.9 ± 1; 3.5 ± 1.2) groups were insignificant (p 0.05), while for In the differences were significant (6.2 ± 1.1 for A and 6.6 ± 1.2 for B). CONCLUSION The color changes for body and cervical regions of multilayered ceramic veneers were not affected by resin color or ceramic thickness, but the incisal area was affected. The translucency of each layer in ceramic veneer fabricated with multilayered blanks should be considered for clinical situations. for A and B groups were significantly higher (6,3±1,2;6,6±1,2) than Bo and Ce for D (4,4±2,4;4,6±2,6 ) and L (4,6±1,4;4,5±1,7) groups (p< 0.05), respectively. Mean differences between Bo and Ce for A (5,1±2,6; 5,3±2,7) and for B (3,9±1;3,5±1,2) groups were insignificant (P≥0.05) while for In the differences were significant (6,2±1,1 for A and 6,6±1,2 for B). Conclusion:The color changes for body and cervical regions of multilayered ceramic veneers were not affected from resin color or ceramic thickness while only incisal area was affected.Translucency of each layer in ceramic veneer fabricated with multilayered blanks should be considered for clinical situations.

Purpose To compare the marginal and internal fit of cobalt‐chromium (Co‐Cr) alloy copings fabricated by with lost wax technique (LW), computer‐aided design and computer‐aided manufacturing (CAD/CAM), and direct metal laser sintering (DMLS). Materials and Methods Thirty‐six tissue level, straight titanium abutments were screwed onto implant replicas. All specimens were embedded in acrylic resin and randomly divided into 3 subgroups according to the fabrication of metal coping: LW, CAD/CAM, and DMLS. In total, 36 (n = 12/group) Co‐Cr implant‐supported metal copings were prepared. Marginal, intermarginal, axial, and occlusal fits of each coping were measured using the silicone replica technique. The data were evaluated statistically using one‐way ANOVA and Bonferioni post‐hoc test (α = 0.05). Results The CAD/CAM group showed significantly lower marginal fit than the LW group and DMLS groups (p < 0.001). The marginal fit of the LW group was not significantly different from the DMLS group (p = 0.721). No significant difference found among the fabrication methods in terms of intermarginal fit (p = 0.913). The CAD/CAM group showed lower axial fit than the LW group (p = 0.026), but there was no statistical difference between the DMLS group and the LW (p = 0.999) and CAD/CAM groups (p = 0.247). No significant differences found among the fabrication methods in terms of occlusal fit (p = 0.158). Conclusions The LW and DMLS groups showed better marginal fit compared to the CAD/CAM group; however, the CAD/CAM group was better than the LW group in terms of axial fit. All fabrication methods demonstrated similar intermarginal and occlusal fit.

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The purpose of this study was to elucidate the origin of initiation of hybrid layer biodegradation. Ninety caries‐free human third molars were divided into three surface groups: enamel, dentin, and NaOCl‐treated dentin. (n = 30/group) Each group was divided into three subgroups (n = 10/group) of luting resin materials with etch‐and‐rinse; self‐etch and self‐adhesive systems. Resin composite blocks and sticks were fabricated and adhered onto dentin and enamel surfaces. The bond strength values were evaluated with micro shear test and statistical analysis were made. On the other hand, teeth were sectioned with a slow‐speed saw into multiple beams. After thermocycling, samples were kept in 50% silver nitrate solution. Samples were analyzed with SEM in back‐scattered mode. According to the micro‐shear bond tests, higher bond strength values were observed in etch‐and‐rinse system. Bond strength values in self‐adhesive and etch‐and‐rinse groups were significantly higher than self‐etch groups in dentin surface and dentin surface treatment with NaOCl. Back‐scattered scanning electron microscope results showed that, different degradation mechanism was observed. The present study indicates that, due to the acid etching in dentin, collagen biodegradation was observed within the hybrid layer. On the enamel surfaces, resin degradation was related with resin monomers in adhesive systems.

Background: Wear and quality assessments of translucent monolithic zirconia and CAD-on â restorations were performed. Methods: Forty 3-unit posterior fixed partial denture (FPD) in 18 patients (age:18-50 years) were made from translucent monolithic zirconia (tm) (Zenostar T) and zirconia-frameworked, lithium disilicate layered (c) (CAD-on), materials in a split-mouth design. Restorations were digitally fabricated and their internal and marginal adaptations were measured before cementation followed by luting (Multilink Speed). Clinical evaluations were made by modified United States Public Health Service criteria at baseline, 6, 12, and 24-months. Wear of the restorations and the antagonists were digitally evaluated after optical scanning of stone casts at 1st week and 24 m through a software (Cerec 4.4). Statistical analysis was made (analysis of variance, Shapiro-Wilk, Friedman and Wilcoxon tests (SPSS 20)) at a = 0.05 significance level. Results: At 24 m, all restorations were clinically acceptable. Insignificant differences were found between tm and c restorations (P > 0.05). Mean internal and marginal adaptation of c restorations were significantly better (145 µm (premolar)-174 µm (molar)) than tm (190 µm (premolar)-207 µm (molar)) (P < 0.05). C restorations significantly caused more wear (0.3 AE 0.1 mm) than tm (0.1 AE 0.07 mm) on the antagonistic dentition (P < 0.05). Conclusions: Translucent monolithic zirconia restorations caused less wear and antagonist wear than CAD-on restorations. CAD-on restorations exhibited higher internal and marginal adaptation.

Purpose: To investigate colour agreement between different shades of Panavia V5 resin cement and their try-in pastes under zirconia-reinforced lithium silicate ceramics. Methods: Forty-four zirconia-reinforced lithium silicate ceramic specimens were prepared at 0.8 AE 0.01 mm thickness. Composite resin tooth-shaded background specimens were obtained in two shades. Resin cement specimens were fabricated at 0.1-mm thickness. Colour difference values (ΔE) between Aquagel and both the try-in paste and resin cement were calculated using the CIE-Lab system. The CIEDE2000 (ΔE00) colour formula was used to determine colour differences. The three-way ANOVA test and a multiple comparisons test were used for statistical analysis (α = 0.05). Results: A statistically significant difference was found between the ΔE00 values obtained from the cement shade colour measurements for all specimens (P < 0.05). According to the three-way ANOVA test, lower ΔE00 values were observed in the try-in paste group compared to the resin cement group. The ΔE00 values were significantly affected by the cement shade and tooth-shaded background (P < 0.05). Conclusions: The colour agreement between the try-in pastes and the corresponding resin cement differed, and the try-in pastes could not mask the dark dental background as much as the corresponding resin cement.

Summary Background/Aim: The aim of this study was to investigate in the esthetic perceptions of 2nd grade dental students before and after training. Material and Methods: A total of 16 photographs which contain golden ratio, buccal corridor, midline deviation, incisal embrasure, lip line, midline diastema, dark triangles and smile arc were shown to 78 dental students (33 male, 45 female). Immediately after the training about the smile esthetics, the same photos were shown again. The effect of gender on esthetic perception was also examined, in addition to assessing the effects of education on esthetic perception. Pearson Chi-square, Fisher’s Exact test and McNemar test were used in the analysis of the results. Results: According to the results of the analysis, it was found that the answers of the smile arc before and after the education were statistically significant (p< 0.05). Accordingly, the rate of correct answers of women is statistically higher than that of men. A statistically significant difference was found between the responses to the gingival appearance in the smile before and after the education (p< 0.05). Conclusions: Based on the limited results of this study, professional dental education may affect the esthetic evaluation of smile. There were differences in the esthetic perception of women and men.

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