Passive fit analysis of laser-sintered, three-unit implant prostheses: an in- vitro study

Abstract

Statement of problem: The accuracy and passive fit of laser sintered implant prostheses have not been assessed. Purpose: To assess if the implant retained prostheses produced with laser sintering technique present an accuracy and passive fit comparable to their milled counterpart. Material and methods: Two regular neck Straumann analogs were placed in a block of PMMA at 15 mm of distance and parallel to one another. The PMMA block was then scanned and two groups of Cobalt-Chrome screw retained, three-unit implant prostheses were fabricated using milling (control) and laser sintering (test) techniques. The prostheses were then screwed on the PMMA block and the vertical marginal gap between the prostheses and the analogs at the implant-abutment junction was measured twice, i) when only one screw was tightened, and ii) when both screws were fully tightened. The average of each marginal gap measurements were compared to assess the difference in term of passive fit between the laser sintered and the milled prostheses. Results: The mean marginal gap of the milled and the laser sintered groups were 23.18 (SD=6.2) and 23.71 (SD=19.5) respectively. Conclusions: Laser sintered prostheses presented a marginal fit comparable to their milled counterpart.