We pathologically investigated the effects of water irrigation during Er:YAG laser irradiation on wound healing in mouse skin. Fifty-one 6-week-old ICR male mice were used in the present study. Dermal wounds were generated on the skin of the backs using the Er:YAG laser at 100 mJ/pulse and 10 Hz with (4 ml/min) or without (control) water irrigation. Mice were then sacrificed on 0, 1, and 3 days after laser irradiation, and the crust of the skin and thickness of the thermal coagulation layer were evaluated pathologically. The epidermis extended faster in the water irrigation group than in the control group on 1 day. The epidermis with keratinized layers became thicker and the crust had completely detached after 3 days in the water irrigation group. The thermal coagulation layer was thinner in the water irrigation group than in the control group. Apoptotic cell death was prominent in the control group. Detachment of the crust was observed after 3 days in 50% of the water irrigation group and 20% of the control group. These results demonstrated that Er:YAG laser irradiation with water irrigation promoted faster wound healing

Ⅰ. INTRODUCTION
 Ⅱ. MATERIALS AND METHODS
  1. Equipment
  2. Animals and laser irradiation
  3. Pathological observations
  4. Measurement of the coagulation layer
  5. TUNEL staining
  6. Statistical analysis
 Ⅲ. RESULTS
  1. Histological observation
  2. Thickness of the coagulation layer
  3. TUNEL-positive cells
  4. Detachment of the crust
 Ⅳ. DISCUSSION
 Ⅴ. REFERENCES

• 유타 호시야(Tokyo Dental College Department of Operative Dentistry) | Yuta Hoshiya
• 테츄아 아마게이(Tokyo Dental College Department of Operative Dentistry, Tokyo Dental College Department of Endodontics and Clinical Cariology) | Tetsuya Amagai
• 나츄코 아이다(Tokyo Dental College Department of Endodontics and Clinical Cariology) | 나츄고 아이다
• 마사히로 푸루사와(Tokyo Dental College Department of Endodontics and Clinical Cariology) | Masahiro Furusawa
• 토시푸미 아주마(Tokyo Dental College Department of Biochemistry) | Toshifumi Azuma
• 요시토 히라이(Tokyo Dental College Department of Operative Dentistry) | Yoshito Hirai
• 타카시 무라마츄(Tokyo Dental College Department of Endodontics and Clinical Cariology) | Takashi Muramatsu correspondence