EFFECT OF SOME TECHNICAL VARIABLES AND RESIN PHASE MODIFICATION ON MICROLEAKAGE OF DIRECT RESIN ) COMPOSITE RESTORATIONS

Abstract

The present in vitro investigation was designed to study the effect of some technical variables and resin phase modification on microleakage of direct resin composite restorations.

The aim of the study was in two folds, the first was to investigate the influence of using light curing resin modified glass ionomer base and adhesiveresin versus adhesive resin systems only, on the microleakage class V composite resins restorations OIJ microleakage on microleakage at thetooth restorations interface. The second, was to study the effect ofthe modifications of resin matrix i.e., the use oftwo resins, containing composite material versus three resins containing composite resin restorations on• the marginal sealing of both occlusal and gingival margins at different time intervals. A total of 120 freshly extracted human molars were used for preparation of 120 standardized class V cavities, The diameters of the cavity was 4 mm for mesio-distal width, 3 mm in occluso-gingival height and 2 mm in depth. They were divided into two euql groups of 60 molars, each according to the resin formulation of composite resins. In the first group the cavities restored with two resins containing composite, while in the second group the cavities were restored with a three resins containing composite. Each group was subdivided into two equal subgroups of 30 molars according to. use of adhesive system only under composite resin or use of adhesive system and a light cured resin modified glass ionomer abase underneath the composite resin. Each subgroup will be divided into three classes relative to the testing period. i.e., after 24 hours, three 1nonths, six ni.onths respectively. The