Wide Post-extractive vs Delayed Normal-diameter Implants: 1 Year Postloading RCT

Objectives: Our purpose was to compare the effectiveness of 6.0-8.0 mm diameter implants, placed immediately after tooth extraction, with 4.0-5.0 mm diameter implants placed in a preserved socket after a 4-month period of healing in the molar region.
Methods: After extraction of 1 or 2 molar teeth, 100 patients requiring immediate post-extractive implants were randomly allocated to immediate placement of 1 or 2 6.0-8.0 mm-wide diameter implants (immediate group; 50 patients) or for socket preservation (delayed group; 50 patients), according to a parallel group design. Four months after socket preservation, 1 or 2 4.0-5.0 mm-wide delayed implants were placed. Implants were loaded 4 months after placement with provisionals and replaced after 4 months by fixed definitive restorations. Patients were followed until 1 year after loading. Outcome measures were: implant failures, complications and peri-implant marginal bone level changes.
Results: Three patients dropped out 1 year after loading from the immediate group vs six from the delayed group. Five implants out of 47 failed in the immediate group (10.6%) vs two out 44 (4.6%) in the delayed group, the difference being not statistically significant (P=0.436). In the immediate group 10 patients were affected by 10 complications, while in the delayed group four patients were affected by four complications. The difference was not statistically significant (P=0.084). Marginal bone levels at implant insertion were 0.04 mm for immediate and 0.11 mm for delayed implants, which was statistically significantly different (P<0.0001). One year after loading, patients in the immediate group lost on average 1.06 mm and those from the delayed group 0.63 mm, the difference being statistically significant (P<0.0001).
Conclusions: One year follow-up data suggest that immediate placement of 6.0-8.0 mm wide diameter implants in molar extraction sockets could cause more marginal bone loss than delayed placement of conventional 4.0 to 5.0 mm diameter implants.