Abstract:

  Background and Aim: studies show that only 50-70% of composite material is polymerized. A polymerization shrinkage of less than one percent has been reported by the manufacturer for a newly introduced silorane based composite material named filtek P90 (3M ESPE, USA). However, only few independent studies are available regarding degree of conversion (DOC) of this material. The purpose of this study was to evaluate the degree of polymerization in filtek P90 compared to Z250 using deferential scanning calorimetry (DSC).

  Materials and Methods : In this experimental study10 composite disks ( 5 sample for each group ), 2x3 millimeter dimensions, were prepared in stainless steel molds and cured for 20 seconds based on the manufacturer instruction using a LEDTurbo( Apoza,Japan ) with 950 mw/cm2 ray power against a black surface to omit light reflection. Samples were kept in boxes far from sun light, in room temperature before taking the DSC test. The degree of polymerization was evaluated in each group by DSC (Perkin Elmer,Norwalk,CT,USA) device. Obtained data was analyzed By statistical Mann-Whitney Test.

  Results : Degree of conversion of Filtek p90 composite measured as 62.56 ± 5.12 whereas degree of conversion of Z250 composite was messaged as : 71.65 ± 5.30. Z250 composite had a higher degree of polymerization compared to Filtek p90 composite. There was statistically significant difference between two groups (p<0.05).

  Conclusion : Composite Z250 has a higher degree of polymerization compared to Filtek P90.

  Key words : Composite resin-DSC-Degree of conversion-Silorane Base