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.

Comparison of the sensitivity for detecting foreign bodies among conventional plain radiography, computed tomography and ultrasonography.

OBJECTIVE: The purpose of this study was to compare the sensitivity for detecting foreign bodies among conventional plain radiography, CT and ultrasonography in in vitro models. METHODS: Seven different materials were selected as foreign bodies with dimensions of approximately 1 x 1 x 0.1 cm. These materials were metal, glass, wood, stone, acrylic, graphite and Bakelite. These foreign bodies were placed into a sheep's head between the corpus mandible and muscle, in the tongue and in the maxillary sinus. Conventional plain radiography, CT and ultrasonography imaging methods were compared to investigate their sensitivity for detecting these foreign bodies. RESULTS: Metal, glass and stone can be detected with all the visualization techniques used in the study in all of the zones. In contrast to this, foreign bodies with low radiopacity, which could be detected in air with CT, became less visible or almost invisible in muscle tissue and between bone and muscle tissue. The performance of ultrasonography for visualizing foreign bodies with low radiopacity is relatively better than CT. CONCLUSIONS: Ultrasonography detects and localizes superficial foreign bodies with low radiopacity in the tissues of the body more effectively than CT and conventional plain radiography. However, CT is a more effective technique for visualization of foreign bodies in air than ultrasound and conventional plain radiography.