title: Mutans streptococci in subgingival plaque of treated and untreated patients with periodontitis.
abstract: BACKGROUND
  The etiology of root caries is thought to be identical to coronal caries, though root caries seem to be more complicated because of the higher susceptibility of exposed roots (dentin) by periodontal therapy to demineralization than intact enamel. This implies that mutans streptococci are the most likely pathogens in the development of root caries. Although it is known that both the numbers of mutans streptococci and the frequency of isolation in root caries lesions are negatively correlated with the distance from the gingival margin, the subgingival sulcus has not been considered a possible habitat for mutans streptococci. However, subgingival occurrence of mutans streptococci in both untreated and treated periodontal patients has not been documented well in the literature.
  
  
  OBJECTIVE
  To investigate the presence and levels of mutans streptococci in the subgingival plaque of patients (n=154) in different stages of periodontal therapy. The subgingival sulcus may be a possible habitat for mutans streptococci. This localisation of mutans streptococci may be of importance in the development of root caries after periodontal surgery.
  
  
  METHODS
  In this cross-sectional study, subgingival plaque samples from 154 consecutive adult periodontitis patients were tested for presence and levels of mutans streptococci and putative periodontal pathogens by anaerobic cultures. These patients were divided into 4 groups based on their stage of periodontal treatment: (1) untreated patients; (2) patients after initial periodontal therapy only; (3) patients in the maintenance phase who not underwent periodontal surgery; (4) patients after periodontal surgery.
  
  
  RESULTS
  The prevalence of mutans streptococci in the 4 study groups varied from 82% in untreated patients to 94% in maintenance patients. The mean proportion of mutans streptococci was 6.65% in maintenance patients versus 1.86% in untreated patients (p=0.005) and 2.51% in patients after scaling and root planing (p=0.041).
  
  
  CONCLUSIONS
  The subgingival area is a microbial habitat for mutans streptococci that may be of importance in the development of root caries in periodontitis patients.
authors: Sections of Clinical Periodontal Microbiology and Oral Microbiology, Department of Oral Biology, Academic Centre for Dentistry Amsterdam, The Netherlands.
authors: W A
authors: WA
authors: Van der Reijden
authors: N
authors: N
authors: Dellemijn-Kippuw
authors: A M
authors: AM
authors: Stijne-van Nes
authors: J J
authors: JJ
authors: de Soet
authors: A J
authors: AJ
authors: van Winkelhoff
mesh_terms: D000328:Adult; D016976:Aggregatibacter actinomycetemcomitans / Q000254:growth & development; D000704:Analysis of Variance; D001439:Bacteroides / Q000254:growth & development; D002167:Campylobacter / Q000254:growth & development; D015169:Colony Count, Microbial; D003430:Cross-Sectional Studies; D003773:Dental Plaque / Q000382:microbiology* / Q000628:therapy; D003774:Dental Plaque Index; D012534:Dental Scaling; D016967:Fusobacterium nucleatum / Q000254:growth & development; D006801:Humans; D008875:Middle Aged; D009910:Oral Hygiene; D010462:Peptostreptococcus / Q000254:growth & development; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000382:microbiology / Q000628:therapy; D010518:Periodontitis / Q000382:microbiology / Q000517:prevention & control / Q000601:surgery / Q000628:therapy*; D016966:Porphyromonas gingivalis / Q000254:growth & development; D018713:Prevotella intermedia / Q000254:growth & development; D012044:Regression Analysis; D017213:Root Caries / Q000382:microbiology; D016745:Root Planing; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013295:Streptococcus mutans / Q000254:growth & development*