RESUMEN
Composite Resin is a kind of polymer that has been recently substituted for Amalgam; therefore biocompatibility of Composite with periodontal tissue should be acceptable and also should not clinically induce inflammation and irritation symptoms in gingival tissue over a long time. The objective of this research is to investigate biocompatibility of posterior composite with periodontal tissue by means of PPD and BOP indices in teeth which have been filled with Composite and intact ones. This is a clinical trial research and a kind of case control in which 40 teeth of 20 patients -15 men and 5 women - were selected from students of Dentistry Faculty of Tehran Medical Science University as the case group with cl II caries in posterior teeth [4,5,6,7] and the outline of preparation was near or 0.5 coronal to gingival which were filled with posterior composite Resin [P60]. PPD indices based on ranking of 1 to 4 and BOP based on Muhlemann category were measured and recorded exactly before operation and 3 and 6 months after in 40 restored case group and 40 control group [intact teeth in opposite quadrant]. Then the results were analyzed by means of SPSS software and tested by Friedman and Wilcoxon Tests. There was no significant difference between BOP Indices in To-Ti and T[2] in case group and also in control group. Further more there was no significant difference in PPD Indices in To-Ti and T; in case and control groups. There was no significant difference between BOP indices in case and control teeth groups in To [exactly before operation]. Also there was no significant difference between mentioned teeth groups in Tl [3 months after operation]. But a significant difference was found between them in T2 [6months after operation] [P=0. 035] Furthermore there was no difference between PPD indices in case and control teeth groups in proximal side of buccal surface in To, Tl and T2 and also no significant difference on the proximal side of lingual surface in To, Tl and T2. Regarding biocompatibility of new generation posterior Composite Resin [like P60] with periodontal tissue, they have not been able to compete with the intact surface of tooth