title: Clinical evaluation of the biological width following surgical crown-lengthening procedure: A prospective study.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the positional changes of the periodontal tissues, particularly the biological width, following surgical crown-lengthening in human subjects.
  
  
  METHODS
  A clinical trial study involving 15 patients was carried out for a period of 6 months. Sites were divided into 3 groups: treated (TT) sites, adjacent (AD) sites and nonadjacent (NAD) sites. Free gingival margin [FGM], attachment level, pocket depth, bone level, biological width [BW] were recorded at baseline, 1, 3 and 6 months. Direct bone level after flap reflection was recorded before and after osseous resection at baseline only. Level of osseous crest was lowered based on BW, and supracrestal tooth structure needed using a combination of rotary and hand instruments.
  
  
  METHODS
  Student t test and ANOVA were used.
  
  
  RESULTS
  Overall, apical displacement of FGM at TT, AD and NAD sites was statistically significant compared to baseline. The apical displacement of FGM at TT site was more when compared to that at AD and NAD sites at 3 and 6 months. The BW at the TT site was smaller at 1, 3 and 6 months compared to that at baseline. However, at all sites, BW was reestablished to the baseline value at the end of 6 months.
  
  
  CONCLUSIONS
  The BW at TT sites was reestablished to its original vertical dimension by 6 months. In addition, a consistent 2-mm gain of coronal tooth structure was observed at the 1, 3 and 6-month examinations.
authors.affiliation: Sri Siddhartha Dental College and Hospital, Tumkur, India.
authors.forename: K S
authors.initials: KS
authors.lastname: Shobha
authors.lastname: Mahantesha
authors.forename: Hema
authors.initials: H
authors.lastname: Seshan
authors.forename: R
authors.initials: R
authors.lastname: Mani
authors.forename: K
authors.initials: K
authors.lastname: Kranti