Influence of platform switching on crestal bone changes at non-submerged titanium implants: a histomorphometrical study in dogs

Objectives: The aim of the present study was to investigate histomorphometrically the influence of platform switching on crestal bone changes at non-submerged wide-body titanium implants in a dog model. Material and Methods: One-stage insertion of sand-blasted and acid-etched screw-type implants with either matching (CAM) or smaller-diameter healing abutments (CPS) were randomly assigned to the lower jaws of nine beagle dogs. The animals were killed after 7, 14, and 28 days of non-submerged healing. Dissected blocks were processed for histomorphometrical analysis. Measurements were made between the implant shoulder (IS) and: -the apical extension of the long junctional epithelium (aJE), -the most coronal level of bone in contact with the implant (CLB), and -the level of the alveolar bone crest (BC). Results: At 7, 14, and 28 days, the mean IS -aJE values were significantly the lowest at CPS implants. However, after 28 days of healing, both groups revealed significantly increased mean IS-BC values at the buccal aspect of the alveolar bone. The difference in IS-CLB and IS-BC between groups was not significant. Conclusions: Within the limits of the present study, it was concluded that both CAM and CPS implants revealed crestal bone-level changes after 28 days of healing.