title: Comparison of surgical stripping; erbium-doped:yttrium, aluminum, and garnet laser; and carbon dioxide laser techniques for gingival depigmentation: a clinical and histologic study.
abstract: BACKGROUND
  Gingival melanin depigmentation procedures are commonly associated with recurrence of pigmentation, which starts with migration of melanocytes from the adjacent free gingiva. The extent and rate of recurrence varies according to the treatment modalities used and duration of follow-up. The aim of this study is to compare the surgical stripping; carbon dioxide (CO2); and erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser techniques for gingival depigmentation and to evaluate their effect on histologic changes in melanocyte activity and clinical repigmentation.
  
  
  METHODS
  In this study, 140 sites from 35 patients with bilateral melanin hyperpigmentation were treated with surgical stripping (two sites per patient), "epithelial-peel" (CO2 laser, 2 to 4 W, continuous wave),and "brushstroke" (Er:YAG laser, 180 mJ, 10 Hz, long pulse) techniques. Surgical microscope monitoring was performed intraoperatively. Patient preference and perception of pain, change in Dummett oral pigmentation index (DOPI), Hedin index, and change in area of pigmentation from baseline to 6 months postoperatively were recorded. Twenty samples each from the three treatment modalities were selected for histologic analysis using hematoxylin and eosin and dihydroxyphenylalanine oxidase special stains.
  
  
  RESULTS
  At the 6-month postoperative visit, 15 of 70 (21.4%) and three of 20 (15%) of the surgical-treated; 10 of 35 (28.6%) and six of 20 (30%) of the Er:YAG-laser-treated; and eight of 35 (22.8%) and four of 20 (20%) of the CO2-laser-treated sites showed clinical and histologic repigmentation, respectively. Paired t test, analysis of variance, and χ(2) tests were used for statistical analyses. P values for comparison of microscopic evaluation, change in DOPI, Hedin index, and area of pigmentation were 0.001, which were statistically significant. Comparison for patient preference and pain indices gave statistically significant values for Er:YAG laser depigmentation (P = 0.001).
  
  
  CONCLUSIONS
  Clinical repigmentation after gingival depigmentation is an outcome of histologic changes in the melanocyte activity and density of the melanin pigments. Surgical stripping for gingival depigmentation remains the gold standard; however, Er:YAG laser and CO2 lasers can be effectively used but with distinct differences.
authors.affiliation: Department of Periodontology and Oral Implantology, MA Rangoonwala College of Dental Sciences and Research Centre, Pune, Maharashtra, India. rashmidr21@yahoo.com
authors.forename: Rashmi
authors.initials: R
authors.lastname: Hegde
authors.forename: Ashvini
authors.initials: A
authors.lastname: Padhye
authors.forename: S
authors.initials: S
authors.lastname: Sumanth
authors.forename: A Sanjay
authors.initials: AS
authors.lastname: Jain
authors.forename: Naresh
authors.initials: N
authors.lastname: Thukral
mesh_terms: D000293:Adolescent; D000328:Adult; D002452:Cell Count; D002465:Cell Movement / Q000502:physiology; D004396:Coloring Agents; D005260:Female; D005500:Follow-Up Studies; D005881:Gingiva / Q000473:pathology; D005882:Gingival Diseases / Q000473:pathology / Q000601:surgery*; D005890:Gingivectomy / Q000379:methods* / Q000523:psychology; D006801:Humans; D017495:Hyperpigmentation / Q000473:pathology / Q000601:surgery*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D053685:Laser Therapy / Q000379:methods* / Q000523:psychology; D054020:Lasers, Gas / Q000627:therapeutic use*; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008297:Male; D008543:Melanins / Q000032:analysis; D008544:Melanocytes / Q000473:pathology; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology; D010149:Postoperative Pain / Q000145:classification; D057240:Patient Preference; D012008:Recurrence; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D004396:Coloring Agents; D008543:Melanins