title: Host response to microbial challenge following resective/non-resective periodontal therapy.
abstract: BACKGROUND
  The host response to microbial challenge depends on the recruitment of homing leucocytes and may be related to the experience to infectious insults over years.
  
  
  OBJECTIVE
  The aim of this study was to investigate the soft tissue reactions to de novo plaque formation at sites treated with either open flap debridement or with the use of resective means during periodontal therapy.
  
  
  METHODS
  Fifteen patients, who had been treated for periodontal disease (severe generalized chronic periodontitis), participated in the study. Surgical therapy was performed using either gingivectomy (GV) or open flap debridement (OFD) procedures in a split mouth design. After 6 months of healing (day 0), two gingival biopsies were obtained, one from the GV- and one from the OFD-treated sites. The experimental gingivitis model was applied and plaque accumulation was allowed for 3 weeks. New biopsies were obtained from the remaining quadrants on day 21 of plaque formation. The biopsies were snap frozen and prepared for immunohistochemical analysis.
  
  
  RESULTS
  Following 3 weeks of plaque accumulation, the size of the lesion in OFD sites was more than twice as large than that in GV sites (0.42 versus 0.19 mm2). In the GV units, the lesion was characterized by almost similar proportions of T cells (CD3+, 6.0%) and B cells (CD19+, 6.6%), while the ICT in OFD sites was dominated by B cells (13.8%). During the 3-week period of plaque formation the increase in cell densities of T and B cells was three times larger in OFD than in GV sites. The proportion of ELAM-1 (CD62+ cells) decreased in GV (-0.4%) and increased in OFD (0.9%) sites.
  
  
  CONCLUSIONS
  The host response that occurred in the gingival sites treated with OFD was more pronounced than the reaction that under similar experimental conditions took place in the regenerated gingiva at sites treated by resective means.
authors.affiliation: Department of Periodontology, Göteborg University, Göteborg, Sweden. N.Zitzmann@unibas.ch
authors.forename: N U
authors.initials: NU
authors.lastname: Zitzmann
authors.forename: J
authors.initials: J
authors.lastname: Lindhe
authors.forename: T
authors.initials: T
authors.lastname: Berglundh
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis*; D001706:Biopsy; D003773:Dental Plaque / Q000276:immunology*; D005890:Gingivectomy; D006801:Humans; D008875:Middle Aged; D010510:Periodontal Diseases / Q000276:immunology* / Q000601:surgery; D013524:Surgical Flaps; D013997:Time Factors
chemical_list: D015703:Antigens, CD