title: An 18-year longitudinal study of untreated mucogingival defects.
abstract: BACKGROUND
  A study was conducted to observe the changes in areas with untreated mucogingival defects over an 18-year period. The results in this group after 4 and 10 years were previously published.
  
  
  METHODS
  Upon entering dental school, a group of 39 freshman dental students were assessed for plaque index, gingival index, probing depth, and width of keratinized tissue. At that time, 112 sites of inadequate keratinized gingiva were found. Seventeen of the original 39 participants with a total of 61 sites were reassessed for the same parameters after 18 years.
  
  
  RESULTS
  The results revealed that 19 sites showed a slight increase in keratinized tissue, 35 were unchanged (for a total of 54 stable sites), and 7 sites showed a slight decrease in keratinized tissue. The mean width of keratinized tissue at the beginning of the study was 1.74+/-0.545 mm and 2.02+/-0.885 mm after 18 years. This represented a small, but statistically significant increase in the width. The plaque index (PI) and gingival index (GI) of this group at baseline (PI = 0.77+/-0.439 and GI = 0.93+/-0.447) and at 18 years (PI = 0.36+/-0.344 and GI = 0.65+/-0.303) indicated a high level of oral hygiene and gingival health.
  
  
  CONCLUSIONS
  It was concluded that in the absence of gingival inflammation, areas with small amounts of keratinized tissue may remain stable over long periods of time.
authors.affiliation: Department of Periodontology, Temple University School of Dentistry, Philadelphia, PA, USA.
authors.forename: A L
authors.initials: AL
authors.lastname: Freedman
authors.forename: K
authors.initials: K
authors.lastname: Green
authors.forename: L M
authors.initials: LM
authors.lastname: Salkin
authors.forename: M D
authors.initials: MD
authors.lastname: Stein
authors.forename: J R
authors.initials: JR
authors.lastname: Mellado
mesh_terms: D003774:Dental Plaque Index; D005881:Gingiva / Q000378:metabolism; D005882:Gingival Diseases / Q000175:diagnosis* / Q000378:metabolism; D006801:Humans; D007633:Keratins / Q000378:metabolism; D008137:Longitudinal Studies; D009061:Mouth Mucosa; D010512:Periodontal Index; D013997:Time Factors
chemical_list: D007633:Keratins