Effect of the different implant protocols on peri-implant bone: a 6-month prospective study in beagle dogs

Objective: To compare the effects of different implant placement and loading protocols on the marginal bone loss (MBL) in beagles by intraoral radiography. Methods and materials: 61 dental implants were inserted on 9 beagle dogs at bilateral lower posteriors according to 8 different protocols: immediate implant placement and immediate loading for 3 months (IIP + IL3) or 6 months (IIP + IL6) and unloading (IIP + UL), immediate implant placement and delayed loading for 3 months (IIP + DL3) or 6 months (IIP + DL6), delayed implant placement and immediate loading for 3 months (DIP + IL3) or delayed loading for 3 months (DIP + DL3) and unloading (DIP + UL). Intraoral radiography was performed to analyze the MBL during each surgery, before and after the implant placement and at 3-month intervals after the procedure. Results: In total, 57 samples were included. There was less MBL (p<0.05) in the IIP + IL3 group (1.22 +/- 0.63 mm) compared to the DIP + IL3 group (1.89 +/- 0.9 mm). The longer the loading time, the more bone loss appeared in the IIP + IL group; however, the results were reversed in the IIP + DL group. The MBL during the latter 3-month period was dramatically decreased compared to the former 3-month period in the IIP + DL3 group (p<0.05). Conclusions: The IIP + IL group seems superior to the DL protocol and the MBL changed significantly during the first three months and thereafter became stable.