title: Comparison of epidermal/dermal damage between the long-pulsed 1064 nm Nd:YAG and 755 nm alexandrite lasers under relatively high fluence conditions: quantitative and histological assessments.
abstract: OBJECTIVE
  The purpose of this study was to compare degrees of epidermal/dermal tissue damage quantitatively and histologically after laser irradiation, to find ideal treatment conditions with relatively high fluence for skin rejuvenation.
  
  
  BACKGROUND
  A number of recent studies have evaluated the clinical efficacy and safety of therapeutic lasers under relatively low fluence conditions.
  
  
  METHODS
  We transmitted the long-pulsed 1064 nm Nd:YAG and 755 nm Alexandrite lasers into pig skin according to different fluences and spot diameters, and estimated epidermal/dermal temperatures. Pig skin specimens were stained with hematoxylin and eosin for histological assessments. The fluence conditions comprised 26, 30, and 36 J/cm2, and the spot diameter conditions were 5, 8, and 10 mm. Pulse duration was 30 ms for all experiments.
  
  
  RESULTS
  Both lasers produced reliable thermal damage on the dermis without any serious epidermal injuries, under relatively high fluence conditions. The 1064 nm laser provided more active fibrous formations than the 755 nm laser, while higher risks for tissue damages simultaneously occurred.
  
  
  CONCLUSIONS
  The ideal treatment conditions for skin rejuvenation were 8 mm diameter with 30 J/cm2 and 10 mm diameter with 26 J/cm2 for the 1064 nm laser, and 8 mm diameter with 36 J/cm2 and 10 mm diameter with 26 J/cm2 for the 755 nm laser.
authors.affiliation: Department of Medical Bio Technology, Dongguk University-Seoul Seoul , Republic of Korea.
authors.forename: Ju Hwan
authors.initials: JH
authors.lastname: Lee
authors.forename: So Ra
authors.initials: SR
authors.lastname: Park
authors.forename: Jeong Ho
authors.initials: JH
authors.lastname: Jo
authors.forename: Sung Yun
authors.initials: SY
authors.lastname: Park
authors.forename: Young Kwon
authors.initials: YK
authors.lastname: Seo
authors.forename: Sung Min
authors.initials: SM
authors.lastname: Kim
mesh_terms: D000818:Animals; D020405:Dermis / Q000502:physiology*; D004817:Epidermis / Q000502:physiology*; D053844:Lasers, Solid-State; D012060:Rejuvenation; D013552:Swine; D013556:Swine, Miniature