Intra-osseous heat generation during implant bed preparation with static navigation: Multi-factor in vitro study.

OBJECTIVES To compare the intra-osseous temperature reached during bone drilling for dental implant placement using open versus closed static surgical guides and evaluate the influence of bone density, osteotomy drilling depth, and irrigation fluid temperature. MATERIAL AND METHODS 960 osteotomies were performed with 2 mm pilot drills in 16 solid rigid polyurethane foam blocks. Two main variables were considered: the guide type (open or closed guide) and bone density (hard (D1) or soft (D4). The blocks were divided into four groups according to the type of surgical template and bone density as follows: group one: closed guide and hard bone; group two: open guide and hard bone; group three: closed guide and soft bone; and group four: open guide and soft bone. A combination of different experimental conditions was used, including different bone osteotomy depths (6 or 13 mm) and irrigation fluid temperatures (5 oC or 21 oC). RESULTS The highest mean temperature was found in group one (28.29±4.02 oC). In the soft bone groups (three and four), the mean maximum temperature decreased compared to groups one and two (dense bone) and was always higher with closed guides (23.38±1.92 oC) compared to open guides (21.97±1.22 oC) (p<0.001). The osteotomy depth and irrigation fluid temperature also significantly influenced the bone temperature (p<0.001), especially in hard bone. CONCLUSIONS The greatest heat generation was observed in high-density bone. The final intra-bone temperature was about 1 oC higher with a closed static surgical guide than with an open guide. The heat generation in osteotomy sites was substantially reduced by cooling the irrigation fluid to 5 oC.