Intraosseous Temperature Change during Installation of Dental Implants with Two Different Surfaces and Different Drilling Protocols: An In Vivo Study in Sheep

Abstract

Background: The intraosseous temperature during implant installation has never been evaluated in an in vivo controlled setup. The aims were to investigate the influence of a drilling protocol and implant surface on the intraosseous temperature during implant installation, to evaluate the influence of temperature increase on osseointegration and to calculate the heat distribution in cortical bone. Methods: Forty Brånemark implants were installed into the metatarsal bone of Finnish Dorset crossbred sheep according to two different drilling protocols (undersized/non-undersized) and two surfaces (moderately rough/turned). The intraosseous temperature was recorded, and Finite Element Model (FEM) was generated to understand the thermal behavior. Non-decalcified histology was carried out after five weeks of healing. The following osseointegration parameters were calculated: Bone-to-implant contact (BIC), Bone Area Fraction Occupancy (BAFO), and Bone Area Fraction Occupancy up to 1.5 mm (BA1.5). A multiple regression model was used to identify the influencing variables on the histomorphometric parameters. Results: The temperature was affected by the drilling protocol, while no influence was demonstrated by the implant surface. BIC was positively influenced by the undersized drilling protocol and rough surface, BAFO was negatively influenced by the temperature rise, and BA1.5 was negatively influenced by the undersized drilling protocol. FEM showed that the temperature at the implant interface might exceed the limit for bone necrosis. Conclusion: The intraosseous temperature is greatly increased by an undersized drilling protocol but not from the implant surface. The temperature increase negatively affects the bone healing in the proximity of the implant. The undersized drilling protocol for Brånemark implant systems increases the amount of bone at the interface, but it negatively impacts the bone far from the implant.

Clinical effects of conventional and underprepared drilling preparation of the implant site based on bone density: A systematic review and meta-regression

“…Many studies have histologically demonstrated that implant insertion could cause overheating or excessive compression of the cortical bone with the formation of microfractures in early MBL [34,35]. Microfractures and overheating of the cortical bone are complications that can occur when placing an implant in an underprepared osteotomy [18,36].…”

“…An in vivo study in sheep by Stocchero et al [34] further showed that cortical overheating during implant insertion was a determining factor for bone healing. The study results demonstrated that a higher temperature (approximately 8°C compared to 4°C of the conventionally prepared site) is present in an underprepared site during implant placement, resulting in a smaller amount of peri-implant bone after healing.…”

Comparison of bone-to-implant contact and bone volume around implants placed with or without site preparation: a histomorphometric study in rabbits

“…Under drilling complications are derived from high insertion torque which may cause bone microfractures and increased temperature generation 27,28 , resulting in compression necrosis of the bone, delayed healing process and increased bone resorption 15,27 . Microfractures occurrence depends on bone density and the discrepancy between the diameter of the implant and the implant's bed 29 .…”

Thermal exposure of implant osteotomies and its impact on osseointegration—A preclinical in vivo study

“…In addition to osteotomy preparation, implant placement itself might also result in a significant temperature increase in an implant osteotomy. Stocchero et al have studied this effect in vivo and found that temperature increase was mainly correlated to the degree of osteotomy under-preparation and associated high-insertion torques (Stocchero et al, 2019). Interestingly, the authors have also shown that osteotomy under-preparation was correlated to higher BIC values but lower bone volumes around the implant.…”