Effect of preheating on the microleakage of bulkfill resin composite restorations in dentinal margins of class 2 cavities

Abstract

Aims: To investigate Effect of preheating on the microleakage of bulkfill resin composite restorations in dentinal margins of class 2 cavities Material and methods: This experimental study performed on 39 extracted human molars, without caries and with mesiodistal and buccolingual dimensions of 8 to12 mm. Class 2 conventional cavities prepared with pulpal depth of 2 mm and a proximal box with width of 3mm and depth of 1.5 mm and 1 mm below CEJ Using a high_ speed turbine and a carbide bur on proximal (mesial and distal) surfaces of all teeth. The cavities in the mesial and distal are cut so that we have dentinal margins on both sides (78 cavities). Then teeth randomly divided into three groups of 13 (26 cavities) which restored using three composite groups that two of them are bulkfill composites and one of them is conventional composite. Then teeth been ready for restoration after the etching and bonding steps. Group 1: teeth restored with Xtrafill composite, group 2: teeth restored with Opus_ bulkfill composite and group 3: teeth restored with Gradia Posterior composite. Each group used in two ways: at room temperature( 24 °c) and after one preheating cycle used up to a temperature of 50°c . Then all types of composites cured for 40 seconds and the teeth placed in fushin solution for 24 hours after preparation. After 24 hours teeth cut in buccolingual direction and examined for microleakge under stereomicroscope with magnification of 40. The results reported as descriptive statistical indicators in the form of number(percentage). For comparing the microleakage of restored teeth with Opus_bulkfill , xtra-fill and Gradia Posterior composites in dentinal margins of class 2 cavities in two groups of preheating and nonpreheating Wilcoxon test used. A probability value less than 0.05 considered a significant level. To analyse the data version 16 of SPSS software will be used. Results: The results of these tests showed that in the preheating group the amount of microleakage was significantly reduced (p <0.001) and also there was no significant difference between the composites tested in terms of microleakage. (p> 0.05)

Conclusion: Preheating up to 50°C reduces the amount of microleakage in the dentinal margin of Class II cavities in both groups of bulkfill composites (Xtrafill and Opus bulkfill) and conventional composite.