The study of Diode laser effect on pulp tissue

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 11672038
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 矯正・小児・社会系歯学
• Research Institution: Tokyo Medical and Dental University
• Principal Investigator: KATO Junji Division of Oral Health Science, Graduate School, Tokyo Medical and Dental University, Research Associate, 大学院・医歯学総合研究科, 助手 (80177451)
• Project Period (FY): 1999 – 2000
• Keywords: Diode laser / pulpotomy / calcified barrier

Research Abstract

The purpose of this study was to examine the wound healing effect of Diode laser on the amputated pulp tissues. This experiment was conducted on the bilateral maxillary first molar teeth of young male Wistar rats, divided into three groups. In group 1 (control group), they received no irradiation on the surface of the amputated pulp. In group 2, the surface of the amputated pulp was irradiated with the continuous wave Diode laser with an output power of 500mW and an irradiation time of 5 seconds. In group 3, the surface of the amputated pulp was irradiated with Diode laser with an output power of 500mW and an irradiation time of 10 seconds.
The condition of Diode laser irradiation was determined by preliminary examination that a high output power of Diode laser produced heat damage to the pulp, in contrast a low output power of that gave no damage to the pulp.
All of the teeth were dressed with a pure calcium hydroxide powder mixed with sterile saline solution and the cavities were sealed with glass ionomer cement, finally histopathological examination of the specimens was performed.
After 14 days, a large amount of calcified barrier consisted of bone like hard tissue was found in both Diode laser groups. However, the inflammation in radicular pulp is often found in group 3 in comparison with group 2. In control group, the calcified dentin like hard tissue barrier was formed at the amputation site. However, in some cases, severe inflammation in radicular pulp and no formation of a calcified barrier were found. These results suggested that Diode laser irradiation on the amputated pulp might be useful for wound healing after pulpotomy. After these serial experiments Diode laser was applied to the clinical pulpotomy cases, which have been good in the period of observation.