Evaluation of the marginal fit of cast and prefabricated cylinders on abutments for implant-supported prostheses

RESUMO

The aim of this study was to evaluate the marginal fit of cylinders cast in a cobalt-chromium alloy from plastic patterns, compared to the fit of prefabricated silver-palladium cylinders. An octagonal stainless steel device measuring 16 mm in height and 10 mm in width was used to hold an implant replica. A 4-mm high standard abutment was screwed to the replica, using a torque force of 20 N/cm2. Over the abutment, 5 cylinders made up of silver-palladium and 5 of cobalt-chromium alloy were fixed by means of titanium screws, using a torque force of 10 N/cm2. Each cylinder was analyzed three times in eight different locations determined by the octagonal faces of the holder device. After the first measurements, the cylinders were loosened and once again screwed under 10 N/cm2. The whole procedure was repeated a third time, counting up 24 readings of the interface for each abutment/cylinder set. The analysis of the abutment/cylinder interface was carried out in light microscope under magnification of 150X, with a green background light. All silver-palladium and cobalt-chromium cylinders were considered to present a satisfactory fit to the abutment. All results were considered as acceptable fit, thus both types of cylinders studied presented the same characteristics regarding their adaptation