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Objective To evaluate the effect of professional experience and lighting conditions on visual shade selection on natural teeth and comparing the visual‐shade‐selection results with those of instrumental methods. Materials and Methods Shade selection was performed on five maxillary central incisors. The 25 observers were divided into five groups according to their professional experience. Observers performed visual‐shade‐selection using shade guide (Vita 3D Master, Vita Zahnfabrik, Bad Säckingen, Germany) under two lighting conditions (4000 and 6500 K) from the cervical, middle and incisal thirds of the teeth. Same teeth were measured using an intraoral scanner (Trios 3Shape, Copenhagen, Denmark) and spectrophotometer (Vita Easyshade Compact, Vita Zahnfabrik, Bad Säckingen, Germany), under the same two lighting conditions. Results Visual‐shade‐selection outcomes were not affected by professional experience under both lighting conditions (P < .05). Outcomes of visual‐shade‐selection and intraoral scanner were not significantly different than that of spectrophotometer (P > .05). Lighting conditions had no effect on the shade measurement outcomes of visual shade selection, Vita Easyshade Compact, and Trios 3Shape (P > .05). Conclusions Shade measurement outcomes were not affected by the lighting conditions (4000 and 6500 K). The shade measurement feature of the T‐3S could be an alternative to V‐ES and VSS. Clinical significance This study suggests professional experience and lighting conditions has no effect on visual shade selection. Trios 3Shape could be used for shade determination as an alternative to a Vita Easyshade Compact spectrophotometer.

This study confirmed that the actual kinematics of reciprocating endodontic motors differ from the manufacturers' set values. Some kinematic parameters were influenced by the clinical usage of the motors.

Objective To evaluate the influence of saliva contamination and cleaning procedures on shear bond strength (SBS) of a self‐adhesive resin cement (SAC) to zirconia surfaces. Materials and Methods A total of 160 sandblasted zirconia blocks were randomly divided into eight groups as follows: No saliva contamination, no cleansing (NC‐NC); contamination with saliva, no cleansing (SC‐NC); no saliva contamination, cleansing with a zirconia primer (ZP; Z‐Bond, Danville Materials, Inc., S. Ramon, California) (NC‐ZP); contamination with saliva, cleansing with ZP (SC‐ZP); no saliva contamination, cleansing with hydrofluoric acid (HF; Ultradent Porcelain Etch; Ultradent Products, South Jordan, Utah) followed by cleansing with ZP (NC‐HF‐ZP); contamination with saliva, cleansing with HF followed by cleansing with ZP (SC‐HF‐ZP); cleansing with ZP, contamination with saliva, cleansing with ZP (ZP‐SC‐ZP); application of ZP, contamination with saliva, cleansing with HF followed by cleansing with ZP (ZP‐SC‐HF‐ZP). Cylindrical resin composite blocks were luted to the zirconia surfaces with SAC (Clearfil SA Cement Automix, Kuraray, Inc., Tokyo, Japan). Specimens were subjected to shear forces at a cross‐head speed of 0.5 mm/min. Data were analyzed with Analysis of Variance and Tukey tests (α = 0.05). Results The bond strength values to zirconia were significantly influenced by saliva contamination (P < .05). The SC‐NC group showed the lowest bond strength values (5.6 ± 1.4 MPa; P < .05). All cleansing or pretreatment agents improved the bond strengths when compared to noncleansing groups, NC‐NC and SC‐NC. Conclusion In situations where saliva contamination is deemed unavoidable, application of ZP after try‐in of the zirconia restoration could be beneficial for the accurate cementation. Clinical Significance During try‐in sessions of fixed dental prostheses, zirconia ceramic restoration may come into contact with saliva and surfaces should be cleansed to obtain an optimal surface for adhesion. Application of zirconia primer to the sandblasted zirconia surface is recommended whether the surface is contaminated with saliva or not.

Purpose:This study evaluated the effects of different adhesive systems on repair bond strength of aged resin composites.Materials and Methods:Ninety composite discs were built and half of them were subjected to thermal aging. Aged and non-aged specimens were repaired with resin composite using three different adhesive systems; a two-step self-etch adhesive, a two-step total-etch adhesive and a one-step self-etch adhesive; then they were subjected to shear forces. Data were analyzed statistically.Results:Adhesive type and aging significantly affected the repair bond strengths (p<0.0001). No statistical difference was found in aged composite groups repaired with two-step self- etch or two-step total-etch adhesive. One-step self-etch adhesive showed lower bond strength values in aged composite repair (p<0.0001).Conclusion:In the repair of aged resin composite, two-step self-etch and two-step total-etch adhesives exhibited higher shear bond strength values than that of one-step self-etch adhesive.