Strategies to achieve fit in implant prosthodontics: a review of the literature.

PURPOSE This paper reviews the literature on advanced strategies that attempt to improve fit in implant prosthodontics with reference to the concept of the "distortion equation." MATERIALS AND METHODS The majority of the articles reviewed were either clinical or technique articles that advocated strategies to improve fit in implant prosthodontics. A limited number of retrospective and prospective clinical trial studies were included as they related to the topic. Reviewed articles were limited to those that addressed advanced strategies to improve fit. All of the scientific studies included in this review used an in vitro experimental design. The advanced strategies were categorized into methods that address intraoral indexing and methods that use the implant master cast. RESULTS Relatively few methods have been scientifically proven to improve fit in implant prosthodontics. Most of the tested strategies still resulted in a slight misfit of the frameworks to the implant abutments/analogues. CONCLUSION Multiple factors preclude that the concept of "passive fit" can be achieved in implant prosthodontics, even with the use of advanced strategies. The use of meticulous, accurate implant prosthodontic procedures and the appropriate use of advanced strategies continue to be the recommended means of achieving precise fit of the implant prosthesis to the intraoral abutments.