Influence of abutments in stress induction by implanted-supported frameworks

Objectives: This study evaluated two techniques indicated to obtain implant-supported fixed prostheses with satisfactory passive fit by means of photoelastic analysis. Methods:Two titanium casts groups were fabricated in a metallic master cast: Group I – three frameworks fabricated by laser welded cylinder technique and Group II – three frameworks cast in one-piece and submitted to Rectification Cylinder System. After optical microscopy evaluation, only the better-fit framework of both groups was submitted to the photoelastic analysis, testing three screw tightening sequences (5/4/3/2/1; 1/2/3/4/5 and 3/2/4/1/5). Subsequent to the first analysis, the selective framework of Group II was sectioned and laser welded to be submitted to a new evaluation. Results:Showed superior stress magnitude in 1/2/3/4/5 and 5/4/3/2/1 sequences of both groups, while 3/2/4/1/5 screw tightening sequence presented better stress results of them. Laser welded cylinder framework illustrated better results, even though had showed superior values of misfit (165ìm) compared to the rectified framework before (54ìm) and after section and vertical laser welded (117ìm). Conclusion:Laser welded cylinder group achieved better results mainly allied to 3/2/4/1/5 screw tightening sequence.