Temperature Threshold Values of Bone Necrosis for Thermo-Explantation of Dental Implants—A Systematic Review on Preclinical In Vivo Research

Abstract

Purpose: Very high or low temperatures will lead to bone damage. The objective of this review was to analyze threshold values for thermal bone necrosis. Methods: Histological animal studies evaluating thermal effects on bone necrosis were selected via electronic and hand searches in English and German language journals until 1 November 2019. The outcome measures were temperature-exposure intervals and laser settings effecting bone damage. Furthermore, investigated parameters were the bone-to-implant contact ratios (BIC) and infrabony pockets around dental implants after thermal treatment. For quality assessment of studies, the CAMARADES study quality checklist was applied. Results: A total of 455 animals in 25 animal studies were included for data extraction after screening of 45 titles from 957 selected titles of the MEDLINE (PubMed), The Cochrane Library, Embase and Web of Science search. The threshold values for bone necrosis ranged between 47 °C and 55 °C for 1 min. A threshold value for cryoinsult and laser treatment has not yet been defined. However, temperatures in the vicinity of 3.5 °C produce a histologically proven effect on the bone and in the surrounding tissue. At 50 °C for 1 min, BIC values significantly decreased and infrabony pockets increased. Bone quality had an influence on the outcome, as cancellous bone suffered higher bone damage from thermal treatment compared to cortical bone. Conclusion: No clear threshold value for bone necrosis is available according to the current literature for warm and cold stimuli. More in-depth and clinical studies are required to provide further insights in assessing the potential of thermal necrosis for implant removal.

Heat Generation by Diode Laser (1064-nm) on Dental Implants. (An in vitro study)

“…Such results may fluctuate if different bone models are used and if different types of implant systems are used due to differences in the reaction of the laser by the surface form (32) . In some studies, bone injury by heat induction was carried out in rabbits causing adverse effects on living bone when the temperature rised above 47°C for 60 s affecting the ability of bone to regenerate (27,33,34) . The overheating at the bone-implant interface may cause bone death and compromise the bone's ability to stay alive as a differentiated tissue (35) .…”

Influence of Drilling Technique on the Radiographic, Thermographic, and Geomorphometric Effects of Dental Implant Drills and Osteotomy Site Preparations

“…Kniha et al stated that a thermal threshold between 47 and 55 °C might cause bone necrosis. In addition, bone density has emerged as a determinant factor, with cancellous bone more susceptible to high temperatures than cortical bone [ 23 ]. However, Trisi et al reported that an increase in temperature up to 60 °C maintained for one minute during osteotomy site preparation did not show statistically significant ( p ˃ 0.05) effects on dental implant osseointegration; however, they recommended careful drilling procedures with sufficient irrigation to avoid peri-implant defects [ 24 ].…”

Reversal of Osseointegration as a Novel Perspective for the Removal of Failed Dental Implants: A Review of Five Patented Methods

“…The extent of bone damage depends on the temperature and duration of its application. Application of heat between 47 • C and 55 • C for 1 min can cause irreversible bone damage [38]. Cold cryoinsults also caused osteonecrosis in an emu bone model [38,39], with the moderated critical temperature of 3.5 • C for the reduction in osteocyte viability below 50%.…”

“…Application of heat between 47 • C and 55 • C for 1 min can cause irreversible bone damage [38]. Cold cryoinsults also caused osteonecrosis in an emu bone model [38,39], with the moderated critical temperature of 3.5 • C for the reduction in osteocyte viability below 50%. The holding time and the rate of temperature change were not considered in the study [39].…”

“…A recent systematic review on preclinical in vivo research revealed no clear threshold values of hot and cold stimuli causing bone necrosis in the existing literature. The authors recommended in-depth clinical studies to gain further insight into the potential of thermal necrosis for implant removal [38]. An in vitro pilot study on the induction of thermal necrosis for implant removal showed significant degeneration of the bone matrix at 51 • C for 10 s and 5 • C for 30 s [40].…”