title: A method to compare four mouthrinses: time to gingivitis level as the primary outcome variable.
abstract: OBJECTIVE
  The experimental gingivitis model is a well-established method in comparing the chemical antiplaque activity of agents and products. The aim of the present study was to use time in order to achieve an exit level of bleeding on probing (BOP) as the primary outcome variable.
  
  
  METHODS
  The study was a single blind, randomised four treatment parallel group design employing 76 healthy volunteers. The cohort was accepted into the study proper if they achieved a level of </= 25% BOP after a 5-week pre-study oral hygiene phase. At baseline, 1, 2, 3, 4, 5 weeks BOP, modified gingival index (MGI) and plaque index scores were obtained from each subject. After baseline, oral hygiene was suspended and subjects rinsed twice daily with one of the test rinses, namely: 1 0.05% cetylpyridinium chloride 2 Control fluoride 3 0.2% chlorhexidine 4 0.3% triclosan Subjects were removed from the study when they achieved >/= 50% BOP. Using the baseline and exit BOP, MGI and plaque, a deterioration rate for each parameter was derived and used as the unit of analysis.
  
  
  RESULTS
  There were highly significant treatment differences for all three parameters. Paired analyses revealed chlorhexidine was highly significantly more effective than the other rinses for all three parameters. CPC and triclosan were not different from the control for BOP, but CPC was significantly different from the control for MGI and plaque, and triclosan was different from the control for plaque. There were no differences between the CPC and triclosan rinses.
  
  
  CONCLUSIONS
  The method achieved the expected result of differentiating between the chlorhexidine and the other rinses. Some modification of the method, primarily to group sizes, should improve specificity. The method has the considerable volunteer appeal of early exit, particularly when allocated to control or low activity treatments for plaque.
authors.affiliation: Division of Restorative Dentistry, Dental School, Bristol, UK.
authors.forename: R
authors.initials: R
authors.lastname: Yates
authors.forename: B H
authors.initials: BH
authors.lastname: Shearer
authors.forename: E
authors.initials: E
authors.lastname: Huntington
authors.forename: M
authors.initials: M
authors.lastname: Addy
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000627:therapeutic use; D002327:Cariostatic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D002594:Cetylpyridinium / Q000008:administration & dosage / Q000627:therapeutic use; D002710:Chlorhexidine / Q000008:administration & dosage / Q000627:therapeutic use; D015331:Cohort Studies; D003773:Dental Plaque / Q000517:prevention & control*; D003774:Dental Plaque Index; D005260:Female; D005459:Fluorides / Q000008:administration & dosage / Q000627:therapeutic use; D005884:Gingival Hemorrhage / Q000517:prevention & control; D005891:Gingivitis / Q000517:prevention & control*; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D009067:Mouthwashes / Q000627:therapeutic use*; D009910:Oral Hygiene; D010512:Periodontal Index; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D013223:Statistics as Topic; D013997:Time Factors; D016896:Treatment Outcome; D014260:Triclosan / Q000008:administration & dosage / Q000627:therapeutic use
chemical_list: D000891:Anti-Infective Agents, Local; D002327:Cariostatic Agents; D009067:Mouthwashes; D014260:Triclosan; D002594:Cetylpyridinium; D005459:Fluorides; D002710:Chlorhexidine