Surface roughness and morphologic changes of zirconia: Effect of different surface treatment

Purpose: The purpose of this study was to investigate the surface roughness and morphologic changes of pre.sintered ZrO2 after sandblasting and erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser application of different intensities.Material and Methods: Eighty pre-sintered ZrO2 cylinders (7 mm diameter, 3 mm height) were prepared and divided into eight groups. Specimens in the control group were not treated. The following treatments were applied: Er, Cr: YSGG laser irradiation with different energy intensities (1-6 W at 20 Hz, with air.water cooling proportion of 65%/55%) and air abrasion with Al2O3 particles (120 µm). Then, all the specimens were sintered. The average surface roughness of each specimen was determined with a profilometer, and the morphology changes of a specimen from each group were evaluated with scanning electron microscope (SEM) analyses. The surface roughness data were analyzed through one.way analysis of variance and Tukeyfs honestly significant difference test (P < 0.05).Results: There were significant differences between 2 and 6 W irradiations and control group. The highest surface roughness value was obtained with 6 W irradiation (8.14 ± 1.26 Ra), followed by the 5 W (7.60 ± 1.12 Ra), 4 W (7.50 ± 0.90 Ra), 3 W (5.86 ± 1.03 Ra), 2 W (4.54 ± 0.53 Ra) and sandblasting group (2.18 ± 0.92 Ra). 1 W laser irradiation (0.80 ± 0.06 Ra) presented Ra values similar to the control group (0.77 ± 0.03).Conclusion: The result of the statistical analyses and SEM images showed that Er, Cr: YSGG laser irradiation with 4-6 W/20 Hz presented significantly effect in surface roughness changes of zirconia than other surface  treatments.Key words: Erbium, chromium: Yttrium, scandium, gallium, garnet laser, scanning electron microscopic, surface roughness, Y-TZP zirconi

Shear bond strength of a self‑etched resin cement to an indirect composite: Effect of different surface treatments

Objectives: The aim of this study was to compare the shear bond strength of resin cement (Rely X‑U200) bonded to differently conditioned indirect composite samples.Materials and Methods: Sixty‑six composite resin specimens (5 mm in diameter and 3 mm in thickness) were prepared with an indirect composite resin (Grandia) and randomly divided into six groups. Surfaces of the samples were treated with one of the following treatments; %37 phosphoric acid etching, sandblasting, 1,5 W, 2 W and 3 W erbium, chromium: Yttrium‑scandium‑gallium‑garnet laser application. An untreated group was used as a control. In each group surface of the sample was analyzed with scanning electron microscopy. The remaining samples (n = 60) were built up with a self‑adhesive resin cement (Rely X‑U200) 3 mm in diameter and 2 mm height. After 24 h water storage at 37°C, the prepared specimens were submitted to shear bond strength test. One‑way analysis of variance was used to analyze the bond strength values of different groups.Results: Highest shear bond strength values were observed in sandblasting group however there were not statistical difference among the tested surface treatment methods.Conclusion: In Shear bond strength of resin, cement was independent of the surface conditioning methods applied on tested indirect resin composite.Key words: Composite resins, dental bonding, resin cements, surface propertie

Effect of intracanal medicament on bond strength of fibre posts

The aim of this study was to evaluate the effect of calcium hydroxide (CH), triple antibiotic paste (TAP) and double antibiotic paste (DAP) on the push-out bond strengths of three different self-adhesive resin cements. Forty-eight single-rooted human maxillary central incisors were selected. The crowns were removed and the root canals were performed. After the irrigation protocols, the post space was prepared. The teeth were then randomly divided into a control group (no intracanal medicament) and three medicament groups (n = 12 for each group). After three weeks, the medicaments were removed using 17% ethylenediaminetetraacetic acid, 2.5% sodium hypochlorite and EndoActivator agitation. The teeth were divided into three subgroups according to the fibre-post luting cement: Maxcem Elite, RelyX Unicem and BisCem. The specimens were sectioned and the push-out test was performed. One-way analysis of variance and Tukey's post hoc tests were used for statistical analyses. Regarding the type of cement, BisCem had significantly lower bond strength values than Maxcem and RelyX. There was no significant difference between the bond strength values of Maxcem and RelyX (p > 0.05). The TAP-RelyX group had the highest bond strength value and the DAP-BisCem group had the lowest bond strength value. RelyX and Maxcem had higher bond strength to root canal dentin than BisCem. The bond strength of BisCem, RelyX and Maxcem was not negatively affected by the use of DAP, CH and TAP as intracanal medicaments