Initial Crestal Bone Loss After Implant Placement with Flapped or Flapless Surgery-A Prospective Cohort Study

Some initial loss of bone around dental implants is generally expected. There is reason to believe that reflecting a mucoperiosteal flap promotes crestal bone loss in the initial phase after an implant has been inserted. The objective of this study was to compare the effect of flapless implant insertion on initial bone loss with that of conventional placement after elevation of a mucoperiosteal flap.

Eighty patients were randomly assigned either to the flapless group (test) or to the group with a full-thickness flap (control). In total, 195 implants were included in the study: 95 of these were inserted flapless (test group), and 100 were inserted by raising a mucoperiosteal flap (control group). Healing occurred unsubmerged for both groups. To assess changes in the peri-implant bone level, the height of the mesial and distal peri-implant bone was measured on digitally calibrated radiographs taken at the time of implant placement and 12 months afterward.

After 1 year, a mean cumulative crestal bone loss of 0.24 ± 0.62 mm was measured. A mean bone loss of 0.55 ± 0.57 mm was found in the group with the mucoperiosteal flap, while a slight mean gain in bone height of 0.09 ± 0.49 mm was found in the test group, a statistically significant difference (P < .001).

Flapless implant insertion caused less peri-implant bone loss than implant insertion with flap preparation. Therefore, the flapless procedure represents a protective and promising method in implant surgery.