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Background/Aim: In recent years, the role of computer aided design (CAD) and computer aided manufacturing (CAM) in dentistry has increasingly become important. However, the influence of different Yb: fiber laser applications on surface roughness of CAD/CAM implant has rarely been studied. The aim of this study is to investigate the effect of different Yb: fiber laser parameters on the surface roughness of CAD/CAM titanium. Material and Methods: Titanium samples, produced by CAD/CAM, were divided into 11 groups according to laser parameters such as scanning types (ST), application angles (AA) and hatch interval (HI). The surface roughness of CAD/CAM titanium was examined for each group. Wettability contact angles (CA) were also determined. Results: The highest surface roughness (43 mm) value was obtained for Group 10 (three-ways ST, 60o AA, 0.07mm HI). The lowest value (2.77 mm) after control group was obtained for Group 6. Surface roughness values, for Group 3, Group 9 and Group 10 were significantly higher than for the other groups (P= 0.000). In contact angle evaluations, the highest contact angle (144o) was observed in Group 10, while the lowest (95o) was observed in control group. Conclusions: Surface roughness was dependent on mixed effect of the laser application parameters. Three-ways ST, 60o AA, 0.07mm HI provided highest surface roughness and wettability contact angles. The surface roughness values of one-way ST, 0.06 mm HI, two-ways HT, 45o AA and 0.08 mm HI and three-ways ST, 60o AA and 0.07 mm HI were significantly higher than for the other groups (P=0.000).

Objective: Laser irradiation is an alternative surface treatment method for roughening zirconia surfaces. The aim of this study was to evaluate the effects of ytterbium-doped fiber laser (YbPL) on zirconia., Background: Zirconia surfaces are resistant to many surface treatment methods, but surface roughness is crucial for adhesion of veneering materials and cements to zirconia., Methods: The zirconia discs were prepared and divided into four groups according to the power of the laser irradiation (5, 12, 17, and 20 W). These groups were divided into five subgroups according to the frequency (25, 40, 60, 80, and 100 kHz). Surface roughness values were measured with a noncontact profilometer, and the mean Ra values were calculated. Wettability was measured with a goniometer. The surface morphology was observed with a scanning electron microscope (SEM). The changes in the surface crystalline structure were analyzed with X-ray diffractometry., Results: Ra values of all groups were higher than the control group. The highest surface roughness value was at 20 W and 100 kHz. Best wettability characteristic was observed at 5 W and 60 kHz. The correlations between Ra and wettability were low but significant. SEM examination of 5 W with different frequencies showed no microcracks, however, melted areas were observed. Remaining groups had microcracks and melted layers. A significantly lower T/M-phase transformation was observed in some groups., Conclusions: YbPL irradiation was effective at roughening the zirconia surface. Although laser treatment affected zirconia surfaces and provided surface roughness, the power and frequency should be adjusted to achieve optimum results.

Objective: The clinical survival rates of the adhesive restorations are limited due to the deterioration of resin-dentin bonds over time, partly due to the endogenous enzymatic activity of dentin. Recently, benzalkonium chloride (BAC) has been shown to effectively inhibit endogenous protease activity of dentin. This study evaluated the effect of different concentrations of benzalkonium chloride (BAC) on the degree of conversion (DC), vickers hardness (VH), setting time (ST) and biaxial flexural strength (FS) of two self-adhesive resin luting cements (RC)., Methods: Two RC SpeedCEM (Ivoclar-Vivadent) and BisCem (Bisco) were modified by addition of 0.1, 0.5, 1, 1.5, 2 wt% BAC. The luting cements without the addition of BAC served as control. The DC (FT-IR/ATR from the bottom of the resin disc), vickers hardness (from top and bottom of the light-cured specimen), setting time (ISO 4049) and biaxial flexural strength (0.6 × 6 mm discs) of the specimens were tested. Data were analyzed using ANOVA and Tukeys HSD., Results: DC results were in the range of 70-80%, with some significant changes in BisCem (p < 0.05). VH values of both materials increased significantly compared to control, with no significant change as the BAC percentage increases. BAC addition influenced the ST differently for both materials. For BisCem, a gradual decrease (p < 0.05) was observed whereas, for SpeedCEM, a gradual increase was observed until 1% BAC (p < 0.05). For FS values, a gradual decrease was observed for both materials with increased amounts of BAC (p < 0.05), compared to the control group., Conclusions: BAC addition of up to 1% seems to be acceptable considering the properties tested. Clinical significance. Incorporation of benzalkonium chloride to self-adhesive resin luting cements during the mixing procedure does not significantly affect the degree of conversion or flexural strength of the luting agent and may be a good option to improve the durability of adhesive interface.