Tetsuya Amagai

Questionnaire Study of the First Educational Seminor for the Safety Management in Clinical Laser Dentistry

In 2010, The Committee of Clinical Training Program in Japanese Society for Laser Dentistry held the third educational seminar for safety management in clinical laser dentistry at the 22nd annual meeting of Japanese Society of Laser Dentistry.The purpose of this questionnaire study was to investigate the current status of dental laser applications as well as in clinic safety management. The data was taken from 53 attendants including 45 dentists and 8 dental hygienists.The participants of the seminar showed a high level of satisfaction with the contents of the seminar and expressed their in interests in participating in the future seminar. Sixty-nine percent of the dentists frequently use lasers in clinic, 31% checked lasers before usage and 82% used lasers approved by the ministry of Health, Labor and Welfare of Japan.The types of lasers used were the Er:YAG (24%), CO2 (23%), Diode (16%), Nd:YAG (16%), low-power laser (11%) and Er, Cr:YSGG (7%).The laser was applied to the treatment of hypersensitive dentin, soft tissue surgery, stomatitis, periodontal pocket, dental caries and temporomandibular joint disorders.These results suggested the necessity to hold this kind of seminar periodically.

Experimental oral soft tissue surgery with a high-repetition-rate Er:YAG laser

Abstract The purpose of this study was to evaluate performance in oral soft tissue surgery and the periodontal tissue interactions resulting from increasing the repetition rate of a pulsed-mode Er:YAG laser system from 10 to 30 pulses per second (pps). Five beagle dogs aged 2 or 3 years old were used in this study. The specific maneuvers were performed for a gingivectomy and the removal of melanin pigmentation. A trial Er:YAG laser, which is adjustable up to 30 pps of repeated rate, was used. As for gingivectomy, the output power was made under eight conditions (35 mJ–30 pps, 35 mJ–20 pps, 70 mJ–10 pps, 70 mJ–20 pps, with or without water). The irradiation condition for the removal of melanin pigment was set at 35 mJ–30 pps with or without water. The observation periods were immediately, 7 and 28 days. Specimens were made and observed under a light microscope. Procedures of the gingivectomy and removal of melanin pigmentation resulted in favorable healing, regardless of the irradiation conditions. Increasing the repetition rate up to the 30 pps with low power significantly improved the smoothness and morphology. The high-repetition-rate Er:YAG laser technology described is advantageous, compared with low-repetition-rate Er:YAG lasers, and is applicable in a variety of oral soft tissue surgical procedures.

Pulpal reaction of Er:YAG laser irradiation by different power/pulse conditions

Abstract In this study, using a prototype Er:YAG laser of which pulse repetition rate can be adjusted up to 30 pps, we histopathologically investigated the damage to pulpal response at the time of cavity preparation in relation to the pulse repetition rate. After the Beagle dogs received systemic anesthesia, a contact tip of 600 μm in fiber diameter was placed in the Er:YAG laser and a Blacks V cavity was prepared under the following radiation conditions with watering. After cavity preparation was completed, the interior of the cavity was cleansed and filled with a hydraulic sealing material. Observation periods lasted both 7 and 28 days. Paraffin sections were obtained via a conventional method, stained with a double-staining of hematoxylin and eosin, and histopathologically investigated for changes in the pulp under a microscope. In both the 7th and 28th day follow-up observation cases, circular disorders such as vasodilation and hemorrhage were found at a high rate in both groups, although inflammatory changes such as infiltration of round cells were few. Under the radiation conditions set in this experiment, it was confirmed that cutting of the dental hard tissue could be made without severe changes to the pulp. Because the pulse repetition rate can be changed, we will be able to study in detail the cutting efficiency with changes in the width of the radiation conditions at various cutting sites, such as the dental enamel, dentine and soft dentine.