Effect of welding of sectioned implant prosthesis on the passive fit and strain on bone
Objective: To evaluate the strain developed in bone before and after joining of a screw retained prosthesis by gas welding technique.
Methodology: Acrylic block of dimension 2.5"x1"x1" was made into which two implant analogues of 10 mm length and 4.2 mm diameter were embedded 15 mm apart. A screw retained bar type cobalt chromium superstructure was fabricated over these implant analogues. A strain gauge was attached on the mesial and distal ends of the specimen and the strain developed was measured on application of a 400 N load. The bar was then vertically sectioned and the strain was measured. The bar was then joined by welding followed by strain measurement.
Result: The combined average strain developed after fabrication of the superstructure was high. After sectioning and rejoining the strain values significantly decreased.
Conclusion: It was concluded that to decrease the strain developed in bone of a multiple unit splinted prosthesis, it should be sectioned and rejoined, as the resultant strain developed is less.