In vitro evaluation of temperature changes in the root canal induced by ultrasonic scalers

Objective To evaluate in vitro the thermal effects induced by four different ultrasonic scalers on the temperature in the root canal during ultrasonic scaling. Methods An extracted lower central incisor provided with a thermocouple in the root canal and a tube, entering the tooth incisally and exiting it apically to simulate an artificial bloodstream, was placed in a model of the lower jaw with soft artificial gingiva. Tested ultrasonic scaler systems included: EMS PM-600, Satelec P-max, Durr Vector and Dentsply Cavitron. The tooth was scaled with each system at full water supply of 21°C. Furthermore, the amount of water supply was determined to maintain during scaling a constant temperature in the root canal. Finally, thermal changes due to scaling without water were assessed. Results Except for the Vector all scaler systems showed a temperature decrease in the root canal. The Vector with water/polish suspension showed a trend towards an increase in temperature. To maintain a constant temperature in the root canal the Cavitron needed twice the amount of water compared with PM-600 and P-max. Without water, all scaling systems induced a temperature increase. Conclusion For safe ultrasonic scaling, care should be taken that the cooling water has room temperature and that, dependent on the scaler system, the proper amount of water is supplied.