title: Healing process of skin after CO2 laser ablation at low irradiance: a comparison of continuous-wave and pulsed mode.
abstract: OBJECTIVE
  The purpose of the present study was to compare the healing process of rabbit's skin after the ablation of continuous wave CO(2) laser and pulsed CO(2) laser at low irradiances.
  
  
  BACKGROUND
  Because of its advantages, the CO(2) laser has been viewed as an alternative to the traditional scalpel. Simple thermal models suggest that suitably short pulses of laser irradiation can leave a smaller thermal damaged zone to ablated tissue, which may lead to faster healing.
  
  
  METHODS
  One continuous-wave (cw, 2 watt) and two pulsed CO(2) lasers (sp(1), 100 Hz, 2 watt; and sp(2), 25 Hz, 2 watt) were used to ablate twelve rabbits' ear skin for 2 min, respectively. After sacrifice at 0, 3, 7, 14, 28, and 56 days postsurgery, gross observation and histological examination were performed.
  
  
  RESULTS
  sp(1) and sp(2) resulted in similar ablation rates to cw laser. At 3, 7, 14, and 28 days postsurgery, the scores of the group cw were significantly lower than both the sp(1) and sp(2) scores (p < 0.01). From 7 to 28 days, wounds of sp1 showed the best histological outcomes.
  
  
  CONCLUSIONS
  At a relatively low irradiance, pulsed CO(2) laser is capable of bloodless skin ablation with improved wound healing. Increasing repetition rate of the CO(2) laser may help to achieve a better surgical outcome. Pulsed CO(2) laser may be a valuable instrument for ablation skin and skin lesions.
authors.affiliation: Department of Endodontics, Showa University School of Dentistry, 2-1-1 Kitasenzoku, Ohta-ku, Tokyo 145-8515, Japan.
authors.forename: Xiaogu
authors.initials: X
authors.lastname: Wang
authors.forename: Nelson Tatsunari
authors.initials: NT
authors.lastname: Ishizaki
authors.forename: Koukichi
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D000818:Animals; D002245:Carbon Dioxide; D062109:Dermatologic Surgical Procedures; D053685:Laser Therapy / Q000379:methods*; D008297:Male; D011817:Rabbits; D012867:Skin / Q000473:pathology*; D014945:Wound Healing
chemical_list: D002245:Carbon Dioxide