Effect of Irrigation, Bur Size and Rotational Speed on Thermographic Heat at Implant Site Osteotomy Interface. An In Vitro Study

Abstract

Objectives: This study aimed to evaluate the impact of drill diameter, rotational speed, and irrigation on critical heat generation (≥ 47°C) at the dynamic bone-drill interface during dental implant osteotomy in pre-existing pilot bone cavities. Material and Methods: Bone samples were cut such that immediate and direct thermographic measurements at the dynamic bone-drill interface were possible. Osteotomy cavities of 2.4 mm width were expanded to either 3.2 or 3.8 mm in cortical bovine bone with a thickness of 3.5 mm, using two-bladed twist drills at rotational speeds of 200, 600, or 1000 rpm, with or without saline irrigation. A logistic regression model was developed to predict the likelihood of reaching temperatures ≥ 47°C during osteotomy based on these parameters. Results: The absence of irrigation, major osteotomy diameter expansion, and higher rotational speeds were identified as significant risk factors for increasing the bone-drill interface temperature by more than 10°C (OR: irrigation 177.53; expansion step 9.94; speed by 400 rpm 4.94). No osteotomy performed at a low rotational speed (200 rpm) resulted in a critical temperature rise in either drill diameter group when irrigation was provided. However, temperatures exceeded 47°C across all groups when irrigation was absent. Conclusions: Dental implant osteotomy procedures without irrigation result in critical heat stress at the bone-drill interface, even at low drilling speeds. Shortened protocols with large drill diameter differences of up to 1.4 mm can be safely implemented when drilling at 200 rpm with irrigation. Osteotomy protocols can therefore be shortened while maintaining safety. Trial Registration: No clinical trial was included in the study.