Insufficient irrigation induces peri-implant bone resorption: an in vivo histologic analysis in sheep.

OBJECTIVES

To measure in vivo impact of dense bone overheating on implant osseointegration and peri-implant bone resorption comparing different bur irrigation methods vs. no irrigation.

MATERIALS AND METHODS

Twenty TI-bone implants were inserted in the inferior edge of mandibles of sheep. Different cooling procedures were used in each group: no irrigation (group A), only internal bur irrigation (group B), both internal and external irrigation (group C), and external irrigation (group D). The histomorphometric parameters calculated for each implant were as follows: %cortical bone-implant contact (%CBIC) and %cortical bone volume (%CBV). Friedman's test was applied to test the statistical differences.

RESULTS

In group A, we found a huge resorption of cortical bone with %CBIC and %CBV values extremely low. Groups B and C showed mean %CBIC and %BV values higher than other groups The mean %CBV value was significantly different when comparing group B and group C vs. group A (P < 0.05). Significant differences in %CBIC were found also between group C and group A (P < 0.05).

CONCLUSIONS

Thermal injury, due to insufficient irrigation, of hard bone caused massive resorption of the cortical bone and implant failure. Drilling procedures on hard bone need an adequate cooling supply because the bone matrix overheating may induce complete resorption of dense bone around implants. Internal-external irrigation and only internal irrigation showed to be more efficient than other types of cooling methods in preventing bone resorption around implants.