Thermomechanical compaction of gutta‐percha: effect of speed and duration

摘要

Summary.The McSpadden technique of obturating root canals with thermoplasticozed gutta‐percha has been used for several years, however the technique has been criticized, among the disadvantages is temperature elevation at the root surface. The objective of this study was to test the hypothesis that the McSpadden technique when used at higher speeds or for longer time than recommended by the manufacturer would result in a temperature rise at the root surface and would also have a determental effect upon linear apical leakage.Niney maxillary incisors were divided ino six groups of 15 teeth whose root canals were prepared and subjected to different filling techniques: 5000 rev/minute for 5 seconds, 10,000 rev/minutee for 5 second, 10,000 rv/minute for 15 minute for 15 seconds, and laterally condensed gutta‐percha. Temperatures were measured by suing two J‐type thermocouples which were at the surface of each root.A strobe was used to controsl the speed of instrument rotation and a stop‐wathch was employed to time each compaction. After obturation the teeth were placed into 1 per cent methylene blue dye for 2 weeks, then the linear extent of dye penetration was measured. Statistical analysis of the data showed that the influence of speed duration of compaction were significant in causing a temperature rise and apical leakage. The results of this study support the hypothesis that the use of the McSpadden technique at a higher speed or for longer duration than recommedned can cause an adverse temperature rise at the root surface and a detrimental effect upon the quality of the apic