Aleksa Markovic ´ Tijana Mis ˇic ´ Biljana Milic ˇic ´ Jose Luis Calvo-Guirado Zoran Aleksic ´ Ana Ðinic ´ Heat generation during implant placement in low-density bone: effect of surgical technique, insertion torque and implant macro design Authors’ affiliations: Aleksa Markovic ´, Tijana Mis ˇic ´, Ana Ðinic ´, Clinic of Oral Surgery, Faculty of Dentistry, University of Belgrade, Belgrade, Serbia Biljana Milic ˇic ´, Department of Medical Statistics and Informatics, Faculty of Dentistry, University of Belgrade, Belgrade, Serbia Jose Luis Calvo-Guirado, Department of Dental Implantology, Faculty of Medicine and Dentistry, University of Murcia, Murcia, Spain Zoran Aleksic ´, Department of Periodontics, Faculty of Dentistry, University of Belgrade, Belgrade, Serbia Corresponding author: Professor Dr Aleksa Markovic ´ Clinic of Oral Surgery Faculty of Stomatology University of Belgrade Dr Subotica 4 11 000 Belgrade, Serbia Tel: +381 11 2685860 Fax: +381 11 2685268 e-mail: maleksa64@gmail.com Key words: bone temperature, implant macrodesign, implant placement, insertion torque, low-density bone, surgical technique, thermocouple technology Abstract Objectives: The study aimed to investigate the effect of surgical technique, implant macrodesign and insertion torque on bone temperature changes during implant placement. Material and methods: In the in vitro study, 144 self-tapping (blueSKY Ò 4 9 10 mm; Bredent) and 144 non-self-tapping (Standard implant Ò 4.1 9 10 mm; Straumann) were placed in osteotomies prepared in pig ribs by lateral bone condensing or bone drilling techniques. The maximum insertion torque values of 30, 35 and 40 Ncm were used. Real-time bone temperature measurement during implant placement was performed by three thermocouples positioned vertically, in tripod configuration around every osteotomy, at a distance of 5 mm from it and at depths of 1, 5 and 10 mm. Data were analysed using Kruskal–Wallis, Mann–Whitney U-tests and Regression analysis. Results: Significant predictor of bone temperature at the osteotomy depth of 1 mm was insertion torque (P = 0.003) and at the depth of 10-mm implant macrodesign (P = 0.029), while no significant predictor at depth of 5 mm was identified (P > 0.05). Higher insertion torque values as well as non-self-tapping implant macrodesign were related to higher temperatures. Implant placement in sites prepared by bone drilling induced significantly higher temperature increase (P = 0.021) compared with bone condensing sites at the depth of 5 mm, while no significant difference was recorded at other depths. Compared with 30 Ncm, insertion torque values of 35 and 40 Ncm produced significantly higher temperature increase (P = 0.005; P = 0.003, respectively) at the depth of 1 mm. There was no significant difference in temperature change induced by 35 and 40 Ncm, neither by implant macrodesign at all investigated depths (P > 0.05). Conclusions: Placement of self-tapping implants with low insertion torque into sites prepared by lateral bone condensing technique might be advantageous in terms of thermal effect on bone. Bone tissue is highly cellular. The preserva- tion of the vitality of the differentiated and undifferentiated bone cells that participate in osseointegration cascade and provide anchor- age of endosseous implants to withstand functional loading is an important prerequi- site for successful implant therapy (Brane- mark et al. 1985; Mavrogenis et al. 2009). However, implant surgical procedures cause mechanical and thermal damage to the bone involved. The degree of thermal injury increases exponentially with increasing tem- perature and exposure time (Abouzgia & James 1997). The threshold temperature value for bone tissue necrosis is 47°C for exposure time of 1 min (Eriksson & Albrekts- son 1983; Eriksson et al. 1984). Therefore, excessive heat induces delayed regeneration as a result of bone cells necrosis as well as implant mobility due to dislocation in the hydroxyapatite mineral lattice structure and accordingly it is considered a factor of early failure of implant therapy (Bonfield & Li 1968; Eriksson & Albrektsson 1983; Eriksson et al. 1984; Mauch et al. 1992; Rimnac et al. 1993; Piattelli et al. 1998). Because of its importance, the factors affect- ing heat generation during implant site prepa- ration have been investigated in many studies (Tehemar 1999; Karmani 2006). But another possible source of bone overheating is the implant placement into the prepared site. Although it is known that some of the energy that is used for implant placement is con- verted into heat, factors that contribute to this process are still not described in literature. We Date: Accepted 25 February 2012 To cite this article: Markovic ´ A, Mis ˇic ´ T, Milic ˇic ´ B, Calvo-Guirado JL, Aleksic ´ Z, Ðinic ´ A. Heat generation during implant placement in low- density bone: effect of surgical technique, insertion torque and implant macro design. Clin. Oral Impl. Res. 24, 2013, 798–805 doi: 10.1111/j.1600-0501.2012.02460.x 798 © 2012 John Wiley & Sons A/S