Passive Fit Analysis of Laser-Sintered, Three-Unit Implant Prostheses: An In Vitro Study.

Abstract

Purpose: To assess if the implant-retained prostheses produced with laser-sintering technique present an accuracy and passive fit comparable to their milled counterpart.

Materials and methods: Two regular neck Straumann analogs were placed in a block of PMMA 15 mm apart and parallel to each other. The PMMA block was then scanned and two groups of cobalt-chromium, 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, (1) when only one screw was tightened, and (2) when both screws were fully tightened. The average of each marginal gap measurement was 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 µm (SD = 6.2) and 23.71 µm (SD = 19.5) respectively.

Conclusions: Laser-sintered prostheses presented a marginal fit comparable to their milled counterpart and represent a clinically valid alternative to their milled counterpart. Int J Prosthodont 2023;36:e53-e60.