Application of Er: YAG Laser to Apicoectomy

Abstract

ently, many studies on the application of Er: YAG laser in the dental field have been reported. Er: YAG laser can ablate dental hard tissues with small thermal damages, and is clinically applied for removal of dental caries. However, there are few studies on apicoectomy using Er: YAG laser. The purpose of this study was to compare apicoectomy using Er: YAG laser and the conventional cutting method in vitro.Extracted single-rooted human teeth were used in this experiment. Root resection was performed with Er: YAG laser (output energy: 70mJ10pps) or a fissure bur mounted to a micro-motor. Resected root surfaces were evaluated with scanning electron microscopy.In addition, cutting efficiency of both methods and dye penetration of the cut surface were compared. After removing the tooth crown of 10 extracted single-rooted human teeth, root canals were cleaned, shaped and obturated. Then, the samples were randomly divided into two groups. Root resection by Er: YAG laser or micro-motor was perfOrtned, and working time was counted and the cut surface area measured. Then, all the root surfaces were sealed with nail polish except the resected surface. All roots were placed into 0.1% methylene blue dye for 7 days, rinsed and air-dried. Finally, they were split and the dye penetration from the resected surface was measured and statistically analyzed.The results were as follows:1. There were no smear layer or debris left on the resected surface cut by Er: YAG laser, and the shape of the cut surface was irregular. On the other hand, both smear layer and debris were observed on the surface cut by the conventional method, and the cut surface was smooth.2. The cutting efficiency of Er: YAG laser and micro-motor was 14.8 (±7.3) sec./mm2 and 4.4 (±1.7) sec./ram2, respectively. Cutting by Er: YAG laser significantly needed more time than that by micro-motor (t-test, P<0.05).3. Dye penetration length in the Er: YAG laser group and micro-motor group from the resected surface was 0.95 (±0.37) mm and 1.07 (±0.70) mm, respectively. There was no significant difference between the two groups.(J. Jpn. Soc. Laser Dent. 8: 23-30, 1997 Reprint requests to Dr. EBIHARA)