A comparison of thermocouple and infrared thermographic analysis of temperature rise on the root surface during the continuous wave of condensation technique

Aim This study was designed to use two methods of temperature measurement t o analyse and quantify the in vitro root surface temperature changes during the initial stage of the continuous wave technique of obturation of 17 sin gle-rooted premolar teeth with standard canal preparations. Methodology A model was designed to allow simultaneous temperature measurem ent with both thermocouples and an infrared thermal imaging system. Two the rmocouples were placed on the root surface, one coronally and the other nea r the root apex. A series of thermal images were recorded by an infrared th ermal imaging camera during the downpack procedure. Results The mean temperature rises on the root surface, as measured by the two thermocouples, averaged 13.9 degrees C over the period of study, whilst the infrared thermal imaging system measured an average rise of 28.4 degre es C at the same sites. Temperatures at the more apical point were higher t han those measured coronally. After the first wave of condensation, the sec ond activation of the plugger in the canal prior to its removal always resu lted in a secondary rise in temperature. The thermal imaging system detecte d areas of greater temperature change distant from the two selected thermoc ouple sites. Conclusions The continuous wave technique of obturation may result in high temperatures on the external root surface. Infrared thermography is a usefu l device for mapping patterns of temperature change over a large area.