Heat generation in 1-piece implants during abutment preparations with high-speed cutting instruments

OBJECTIVES: Evaluation of heat generation in 1-piece implants according to 3 variables: preparation time, bur type, and preparation environment. MATERIALS AND METHODS: Study implants were 1-piece designs with the same endosseous dimensions and surface microtexture, but with abutment sections that were either conical in shape, which required clinical preparations to shape and establish a restorative finish line (test), or with a pre-machined shape and restorative margin, which required minimal preparations (control) to accommodate a cemented crown. Burs were either carbide (group 1) or diamond (group 2), and the preparation environment was either ambient air or under water spray. An infrared camera was used to measure temperature changes in the exposed endosseous implant threads during grinding procedures. Three endosseous zones of the implant body were defined for heat measurements: crestal bone region (SP01), middle of the threaded region (SPO2), and apical region (SPO3). Grinding was performed in either ambient air or under water spray. The abutment was reduced to a 2.0 mm height, and one side was ground down to a 30 degree angle. RESULTS: Highest heat elevations were concentrated in SP01, followed by SP02 and SP03. Average temperature changes in SP01 showed that preparation time and environment significantly affected heat generation but not bur type. Lowest temperatures were exhibited by control implants prepared under water spray. Bur type (carbide or diamond) did not affect temperature changes. CONCLUSION: Intraoral implant abutment preparations can transfer heat to the bone capable of impairing osseointegration.