627COMPARATIVE INVITRO EVALUATION OF MARGINAL ACCURACY OF FOUR PROVISIONAL RESTORATIVE MATERIALSBackground: One of the factors that determine the success of a provisional restoration is adequate marginal accuracy. Obtaining the best possible marginal adaptation of provisional restoration effectively prevents plaque accumulation and protects the pulp from thermal, bacterial and chemical insults. Aim & Objective: The aim of study was to evaluate and compare the marginal accuracy of four commercially available bis-acryl composite resin provisional restorative materials using direct technique of fabrication. Material and method: A total of 60 provisional restorations were made using 4 different commercially available bis-acryl composite resin provisional restorative materials: Protemp II, Integrity, Cool Temp, Tempofit(n=15) using direct technique. An artificial maxillary right first molar ivorine tooth was prepared for complete crown restoration with a 1 mm chamfer finish line and a taper of approximately 5 degrees and then casted in non precious Ni-Cr alloy and 1 vertical reference line was marked at the midpoint of metal die finish line, each on mesial, distal, buccal and palatal sides. The provisional restorations were fabricated using four bis-acryl composite resin on this metal die with a vinyl polysiloxane impression as matrix. The marginal discrepancies were measured using stereomicroscope at 30X magnification using Image J software. Statistical analysis of the data was done with one way analysis of variance (ANOVA) and Duncan’s Multiple Range Test. Results: Amongst the four bis-acryl composite resin provisional restorative materials tested, the maximum marginal accuracy was shown by Protemp II (mean 98.45 µm) followed by Tempofit (mean 106.93 µm), Integrity (mean 110.13 µm) and Cool Temp showed the least marginal accuracy (mean 114.12 µm). No significant difference in marginal accuracy was found between the four bis-acryl composite resin provisional restorative materials. (p<0.076). Conclusion: The maximum marginal accuracy was shown by Protemp II, followed by Tempofit, Integrity and Cool Temp bis-acryl composite resin provisional restorative materials. No significant difference was found in the marginal accuracy of materials.drmukesh.mds@gmail.comResearch912019Marginal adaptation,Marginal accuracy,Finish line,StereomicroscopyMukesh Kumar,Vikas B. Kamble,Raviraj G. Desai,Kashinath C. Arrabi,Debashis PanigrahiDepartment of dentistry, S.K.M.C.H, Muzaffarpur, Bihar, India,Department of Prosthodontics, P.M.N.M Dental College & Hospital, Bagalkot, Karnataka, India,Department of dentistry,ISPAT General Hospital, Rourkela, India,Department of dentistry,ISPAT General Hospital, Rourkela, India,Department of dentistry,ISPAT General Hospital, Rourkela, India