The effect of three different curing methods on the microleakage of cl V posterior composite restorations

The effect of three different curing methods on the microleakage of cl V posterior composite restorations Dr. N. Mohammadi* - Dr. P. Alizadeh Oskoee* - Dr. S. Savadi Oskoee*- Dr. A . Soleyman zadeh** *- Assistant Professor of Esthetic & Operative Dentistry Dept. - Faculty of Dentistry – Tabriz University of Medical Sciences.*- Dentist. Background and Aim: Light-cured composites have become almost universal in modern clinical dentistry. Unfortunately, these materials have demonstrated critical limitations such as postoperative sensitivity and polymerization shrinkage. The aim of this study was to evaluate the effects of three curing modes on the microleakage of class V composite restorations. Materials and Methods: In this experimental in vitro study, class V cavities were prepared on the buccal surfaces of 90 extracted human molar and premolar teeth and were randomly divided into 3 groups. All teeth were etched followed by bonding and composite filling. Three different methods were used for curing: conventional, 750 mw/cm2/40s pulse delay, 400 mw/cm2/5s-5 minutes delay-750 mw/cm2/35s and soft start, beginning at 150 mw/cm2 and increasing to 750 mw/cm2 during 15 seconds and remaining for another 35 seconds. After polishing, the specimens were stored in a 37°C incubator, thermocycled (500 cycles) and immersed in basic %0.5 fushin. Longitudinal buccolingual sections of all teeth were scored for marginal dye penetration under a stereomicroscope. Kruskal-Wallis test was used for statistical analysis. Results: Leakage was observed in all groups but no significant difference was found in the microleakage scores among the three light-curing techniques, used in this investigation. Conclusion: These findings suggest that the 3 studied light-curing methods may have no effect on the microleakage of class V posterior composite restorations. Key words: Microleakage - Composite resin - Bonding agents - Pulse delay - Soft start