CEMENTATION OF VENTED CROWNS WITH LOW DEFORMATION

Crown deformation during cementation was measured with a circumferenti al strain gauge. The effects of different seating forces (3, 10 and 25 N), three different cements (Phosphacap, Ketac-cem Applicap and Fuji- cap I) and the presence or absence of venting on deformation and seati ng discrepancy were investigated. Forty mu m of cement space was provi ded for all experiments. Venting increased deformation and reduced sea ting discrepancy, whilst increased force increased deformation and dec reased seating discrepancy. Ketac-cem Applicap allowed the lowest seat ing discrepancy with median crown deformation. It was possible, by usi ng venting, low forces (10 N) and Ketac-cem Applicap, to achieve a low marginal discrepancy with low crown deformation. Venting also diminis hed the seating discrepancy to acceptable levels when higher forces (2 5 N) were used with Phosphacap.