Lateral static overload on immediately restored implants decreases the osteocyte index in peri-implant bone: a secondary analysis of a pre-clinical study in dogs.

Abstract

This animal study was conducted to evaluate the osteocyte index in the peri-implant bone around immediately restored implants under static lateral overload. Seven mongrel dogs received three implants on each side of the mandible. Forty-two implants were distributed into three groups (14 implants per group); each animal received two implants connected to a 4.5-mm opened expansion device (experimental group); in the other mandible side, two implants were connected into an expansion device without activation (control group); one implant each side of the mandible was left submerged (unload group). After 4 months under daily mechanical and chemical plaque control, the animals were euthanized; dental implants and surrounding bone were removed and processed to obtain thin ground sections. Histomorphometry was used to evaluate the osteocyte index in the peri-implant bone contact to implant. A higher, statistically significant mean number of osteocytes × 10-5 μm2 (54.74 ± 23.91) was found in the control group compared with the test group (22.57 ± 22.55) (p = 0.0221). The correlation between percentage of bone-implant contact and osteocyte index for submerged implants was not statistically significant (p = 0.2667), whereas the value for immediately loaded implants was statistically significant (p = 0.0480). The lower number of osteocytes in the peri-implant bone around overloaded implants could be related to the need for functional adaptation of the bone tissue to overloading and to the hypothesized involvement of the osteocytes in the maintenance of the bone matrix in the control group. Osteocytes play a pivotal role in bone adaptation to mechanical loading, and the osteocyte network has been regarded as being the main mechanosensory mechanism.