RESUMO
STATEMENT OF PROBLEM: High stress concentration on the crestal cortical bone has been regraded as a major etiologic factor jeopardizing long term stability of endosseous implants. PURPOSE: To investigate if the design characteristics of crestal module, i.e. internal type, external type, and submerged type, affect stress distribution on the crestal cortical bone. MATERIAL AND METHODS: A cylindrical shaped implant, 4.3 mm in diameter and 10 mm in length, with 3 different crestal modules, i.e. internal type, external type, and submerged type, were analysed. An axisymmetric scheme was used for finite elment formulation. A vertical load of 50 N and an oblique load of 50 N acting at 45degrees with the implant's long axis was applied. The peak crestal bone stress acting at the intersection of implant and crestal bone was compared. RESULTS: Under vertical load, the crestal bone stress was high in the order of internal, external, and submerged types. Under the oblique loading condition, it was in the order of internal, submerged, and external types. CONCLUSION: Crestal module design was found to affect the level of the crestal bone stresses although the actual amount was not significant.