INFLUENCE OF COMPOSITE RESIN PLACEMENT TECHNIQUES ON MICRO LEAKAGE AT THE GINGIVAL SEAT OF CLASS II CAVITY PREPARATION

Abstract

Aim of the study: To evaluate the microleakage at the gingival seat of the proximal class II cavity prepared at 1mm distance above the cement enamel junction restored with bulk fill composite resin material using different placement techniques. Materials and Methods: Forty sound extracted human permanent premolars used in the study. Standardized class II cavities (occluso-mesial and occluso- distal ) were prepared in each tooth, with the cervical margin of the proximal box located 1 mm occlusal to the cemento-enamel junction (CEJ). The teeth were randomly distributed to four groups with 10 specimens each (n=20 cavities) according to packing techniques. In each group, a total-etch adhesive was applied, followed by composite resin that was applied according to; Group I: using bulk technique, Group II: horizontal layering technique, Group III: wedge - shaped layering technique, Group IV: vertical layering technique. All restored specimens were soaked in 2% methylene blue dye for 24 hours, and sectioned for microleakage evaluation using stereomicroscope. Data were collected and statistically analyzed. scanning electron microscope ( SEM) for marginal adaptation and the presence or absence of gaps formed at the margins and of eight samples selected as two sample from each group in the study. The images were taken of the gingival margin at a magnification of1000x. The result : showed no statistical significant differences (p=.610) on comparison of microleakage score by different technique, but it was noticed that bulk technique had the highest mean and median for microleakage score (3.0+- 1.451 &4)and the horizontal, vertical and oblique techniques had the lowest mean scores. Conclusions: Microleakage could not be completely eliminated by any of the testing packing techniques used in the study even with the newly developed Bulk-fill composite resin material. Horizontal packing technique showed the best results in terms of marginal seal with Bulk-fill composit. Key words: Microleakage, Class II, Bulk- fills composite, Composite placement Techniques