Comparative Evaluation of Microleakage with Different Composite Placement Technique in Preparation with High C Factor-An In vitro Study

Objective: To evaluate and compare the effect of different composite placement technique on microleakage in class I composite resin restoration with high C factor. Method: Standardized class-I cavities were prepared on 90 caries-free, extracted human premolars and were randomly assigned to three groups:  Horizontal incremental curing was done; each increment of thickness 1.5 mm was cured one after the other using curing unit (Rotex, Taiwan).  Concave surface was obtained with a ball burnisher on the first increment and cured for 20 seconds; subsequently, the next increment was placed and similarly cured.  Cavities were filled with resin, short of the occlusal surface; two cuts (mesiodistal and buccolingual) were made through the condensed resin and cured for 20 seconds, followed by addition of resin in the gaps created by the cuts and additional curing for 20 seconds. The specimens were stored in distilled water for three months and then subjected to thermocycling, followed by immersion in 0.5% methylene blue dye for 24 hours. The teeth were sectioned longitudinally and evaluated for microleakage under stereomicroscope, and the scores obtained were analysed with Mann whitney test and Kruskal-Wallis nonparametric test. Result: The comparison of groups was statistically significant between Group I, Group II and Group III. Conclusion: split increment horizontal placement technique were capable of generating an effective bonding at the tooth/restoration interface followed by incremental horizontal placement technique and scoop shaped (concavity) technique.