A novel standardized bone model for thermal evaluation of bone osteotomies with various irrigation methods

作者：Strbac Georg D^*; Giannis Katharina; Unger Ewald; Mittlboeck Martina; Watzek Georg; Zechner Werner

来源：Clinical Oral Implants Research, 2014, 25(5): 622-631.

DOI：10.1111/clr.12090

• standardized testing specimen
• dental implants
• multiple temperature sensors
• combined irrigation
• implant osteotomies
• external irrigation
• internal irrigation
• thermal osteonecrosis
• implant drills
• heat generation

Objectives
Based on a novel standardized bovine specimen, the aim of this study was to investigate thermal effects of different irrigation methods during intermittent and graduated drilling.
Material and methods
Temperature changes during implant osteotomies (n=320) of 10 and 16mm drilling depths with various irrigation methods were investigated on manufactured uniform bone samples providing homogenous cortical and cancellous areas and analogous thermal conductivity comparable to human bone. Automated sequences were performed with surgical twist drills of 2mm null and conical drills of 3.5, 4.3 and 5mm null . Real-time recording of temperature increase was done using two custom-built multichannel thermoprobes with 14 temperature sensors at a predefined distance of 1 and 2mm to the final osteotomy. The effects of drilling depth, drilling diameter and irrigation methods on temperature changes were investigated by a linear mixed model.
Results
Using this uniform bone specimen, the greatest temperature rise was observed without any coolant supply with 29.87 degrees C, followed by external with 28.47 degrees C and then internal with 25.86 degrees C and combined irrigation with 25.68 degrees C. Significant differences (P <= 0.0156) between drill depths of 10 vs. 16mm could be observed with all irrigation methods evaluated. With each of the irrigation methods, significantly higher temperature changes (P<0.0001) during osteotomies could be observed between twist drills of 2mm null and conical drills of 3.5, 4.3 and 5mm null . During 10 and 16mm drilling osteotomies, external irrigation showed significantly higher temperatures (P<0.05) for all conical drills compared with internal or combined irrigation, respectively. Significantly lower temperatures (P<0.05) could be detected with internal or combined irrigation for the use of conical drills with various diameters and drilling depths.
Conclusions
This fully standardized bone model provides optimized comparability for the evaluation of bone osteotomies and resulting temperature changes. As regards the efficiency of the various irrigation methods, it could be demonstrated that internal and combined irrigation appears to be more beneficial than external irrigation.

• 出版日期2014-5