TO COMPARE THE MARGINAL FIT, INTERNAL GAP AND FIRING SHRINKAGE OF METAL CERAMIC CROWN FABRICATED BY CAD-CAM AND CONVENTIONAL METHOD:AN INVITRO STUDY

Purpose: The purpose of this in vitro study is to compare the marginal fit , internal gap and firing shrinkage of metal ceramic crown fabricated by cad-cam and conventional method.

Materials And Methods: Atotalof30workingmodels,i.e.15modelseachgroup:conventionallost-waxandmillingwere used.Marginaldiscrepancywasevaluatedattheframeworkandporcelainstepsthroughscanningunder a stereomicroscope. Then, the crowns were cemented to the related die and the marginal gap was measuredundera stereomicroscopeandthensectioningwasdoneandinternalgapwasevaluatedusing scanning electron microscopy (SEM). The data was analyzed using the independent t test and the one- way analysis of variance (ANOVA). The significance level was set at0.05

Results: Among the experimental group, group 2 cad cam shows the better marginal gap in all aspect compare to group 1 conventional technique in both beffore after ceramic firing. Group 1 shows the better internal fit at 4 places out of 5 that is marginal opening area was better in group 2.

Conclusion: Withinthelimitationofthisinvitrostudy,itwasconcludedthatforallthefeaturesCAD-CAM techniques gave better results except internal gap, when compared with the conventional methods and there was a significant statistical difference between the two comparisongroups.