In Vitro Evaluation of Temperature Increase on the External Root Surface During Root Canal Shaping using Single File System

Abstract

During rotary instrumentation frictional force generates heat along the root canal walls due to difference in velocities between the two sliding surfaces.Surface and near surface temperatures can become raised enough to cause changes in the structure and biological behaviour of the adjacent tissues may cause complications like tooth ankylosis, bone necrosis and resorption.

Objective:The study aims to evaluate the temperature changes on the external root surface during root canal preparation with three different single file rotary systems in vitro.

Materials and Methods:

The study was approved by institutional ethical committee. Sixty sound mandibular first premolars were collected. Access cavity was prepared and working length was determined by placing a size 15 K file until the tip was observed at the apical plane. All root canals were instrumented using a size-20 K-type hand file until the file moved freely within the canal. The teeth were mounted vertically into self-curing 4 mm acrylic resin rings, and the root surfaces were exposed. The samples were randomly divided into three groups of 20 teeth each according to the 3 experimental single file systems. During the tooth preparations, the temperature changes were measured for all samples using a noncontact infrared thermometer.

Statistical analysis

The Kruskal– Wallis analysis of variance was used for statistical analysis. The level of significance was 5% (P < 0.05).

Results: The temperature increase caused by the Neolixneoniti file system were lower (P < 0.05) whereas Wave One file caused the maximum temperature increase.

Conclusion

NeolixNiTi file is safer than Wave One and One curve single file sytems in context of temperature rise in the external root surface. This may help avoid the harmful effect on the periodontium while shaping the canal in clinical situation.