title: Staining and calculus formation after 0.12% chlorhexidine rinses in plaque-free and plaque covered surfaces: a randomized trial.
abstract: OBJECTIVE
  Studies concerning side effects of chlorhexidine as related to the presence of plaque are scarce. The purpose of this study was to compare the side effects of 0.12% chlorhexidine gluconate (CHX) on previously plaque-free (control group) and plaque-covered surfaces (test group).
  
  
  METHODS
  This study had a single-blind, randomized, split-mouth, 21 days-experimental gingivitis design, including 20 individuals who abandoned all mechanical plaque control methods during 25 days. After 4 days of plaque accumulation, the individuals had 2 randomized quadrants cleaned, remaining 2 quadrants with plaque-covered dental surfaces. On the fourth day, the individuals started with 0.12% CHX rinsing lasting for 21 days. Stain index intensity and extent as well as calculus formation were evaluated during the experimental period.
  
  
  RESULTS
  Intergroup comparisons showed statistically higher (p<0.05) stain intensity and extent index as well as calculus formation over the study in test surfaces as compared to control surfaces. Thus, 26.19% of test surfaces presented calculus, whereas calculus was observed in 4.52% in control surfaces.
  
  
  CONCLUSIONS
  The presence of plaque increased 0.12% CHX side effects. These results strengthen the necessity of biofilm disruption prior to the start of CHX mouthrinses in order to reduce side effects.
authors.affiliation: School of Dentistry, Division of General Dentistry, Franciscan University Center, Santa Maria, RS, Brazil. fabriciobzanatta@yahoo.com.br
authors.forename: Fabrício Batistin
authors.initials: FB
authors.lastname: Zanatta
authors.forename: Raquel Pippi
authors.initials: RP
authors.lastname: Antoniazzi
authors.forename: Cassiano Kuchenbecker
authors.initials: CK
authors.lastname: Rösing
mesh_terms: D000328:Adult; D002710:Chlorhexidine / Q000009:adverse effects / Q000031:analogs & derivatives*; D003728:Dental Calculus / Q000737:chemistry / Q000209:etiology*; D003773:Dental Plaque / Q000737:chemistry / Q000188:drug therapy*; D003777:Dental Prophylaxis / Q000009:adverse effects; D005891:Gingivitis / Q000503:physiopathology; D006801:Humans; D008297:Male; D009067:Mouthwashes / Q000009:adverse effects*; D010512:Periodontal Index; D016037:Single-Blind Method; D013499:Surface Properties; D013997:Time Factors; D014075:Tooth Discoloration / Q000209:etiology*
chemical_list: D009067:Mouthwashes; C010882:chlorhexidine gluconate; D002710:Chlorhexidine