title: Preprosthetic periodontal surgery in the interproximal area with modification of the COL area: anatomic and histologic study in dogs.
abstract: BACKGROUND
  Due to its concave morphology, a COL creates difficulties for proper oral hygiene. When this characteristic is accentuated by tooth position or caries and when restorations are necessary, they should be corrected by preprosthetic surgery. However, there are no data proving the efficacy of the procedures. The purpose of this study was to evaluate tissue response to preprosthetic surgery to modify COL morphology.
  
  
  METHODS
  Five mongrel dogs received apically positioned flaps, osteotomy/plasty, and RAI (restorative alveolar interface technique) on the maxillary right third bicuspid and first molar; on the same teeth on the left side, a large tissue excision similar to gingivectomy and RAI were performed. Histologic specimens stained with hematoxylin and eosin and Mallory were evaluated at hour 0 and 1, 2, 3, and 4 weeks under light microscopy.
  
  
  RESULTS
  At hour 0, hemorrhage in the remaining interproximal tissue on the left side, and denuded bone modified by the osteotomy on the right side, were observed. At 1 week, both sides showed the presence of granulation tissue and the beginning of reepithelialization and fiber formation. At 2 weeks, the papillae were rebuilt and epithelialized, with fewer inflammatory cells and dilated blood vessels, with a convex morphology. At 3 weeks, the papillae were convex and saddle shaped, with thicker epithelium and denser connective tissue. The general aspect was similar to attached gingiva. However, on the right side, the total extension of the interproximal tissues was longer and had a less accentuated convex curvature. At 4 weeks, the tissues were more mature, but the morphologic and histological findings were similar to 3 weeks.
  
  
  CONCLUSIONS
  Both techniques modified the COL morphology, suggesting that the RAI technique was effective; but the apically positioned flap with osteotomy and RAI created a more extensive convex surface and more interproximal space for the prosthesis. It is recommended that this technique be considered for use in humans.
authors.affiliation: Department of Oral Surgery and Periodontology of the School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil. novaesjr@.forp.usp.br
authors.forename: A B
authors.initials: AB
authors.lastname: Novaes
authors.forename: A B
authors.initials: AB
authors.lastname: Novaes
authors.forename: P T
authors.initials: PT
authors.lastname: De Oliveira
mesh_terms: D000539:Alveolar Process / Q000601:surgery; D000541:Alveolectomy / Q000379:methods; D000818:Animals; D004285:Dogs; D005881:Gingiva / Q000601:surgery*; D005890:Gingivectomy / Q000379:methods*; D008297:Male; D013516:Oral Surgical Procedures, Preprosthetic / Q000379:methods*; D010027:Osteotomy / Q000379:methods; D013524:Surgical Flaps