title: Do caries explorers transmit infections with persons? An evaluation of second molar caries onsets.
abstract: Dental caries explorers may become contaminated during routine caries examinations with pathogenic organisms and thereby potentially transmit infections from one tooth to another within a patient. The purpose of this study was to test the hypothesis that the contamination status of explorers influenced the caries risk of second molars. Two explorer contamination statuses were defined: (1) contamination status 1--explorers which had probed a carious molar just prior to examining the second molar, and (2) contamination status 2--sterile explorers versus explorers which had probed several teeth. Caries examinations were performed by 4 dentists on a cohort of 4th grade students in Belize City. The examination dates and sample sizes (n) were: September-October 1989 (n = 1,277), January 1991 (n = 1,111), and January 1992 (n = 961), and January-February 1993 (n = 861). Within this cohort, there were 221 subjects who (1) had at least one pit and fissure carious onset on a caries-free second molar, (2) had no evidence of dental treatments, and (3) were examined by the same examiner during the entire study. After adjusting for confounding variables, the examination of a second molar with a dental caries explorer in either contamination status 1 or 2 had no substantial effect on the caries risk (rate ratio 0.95, 95% confidence interval: 0.77-1.18, and rate ratio 1.18, 95% confidence interval: 0.89-1.56, respectively). If a true rate ratio of 1.7 or greater was associated with the contamination status 1 and 2, these analyses had more than 99 and 80% probability of detecting it, respectively.
  
  
  CONCLUSIONS
  Examining a sound second molar with a contaminated dental explorer either does not affect the caries risk, or results in such a small increase in caries risk that it can only be reliably identified in studies where the exposure of sound teeth to contaminated dental explorers is randomized.
authors.affiliation: Department of Dental Public Health Sciences, School of Dentistry, University of Washington, Seattle 98195, USA.
authors.forename: P P
authors.initials: PP
authors.lastname: Hujoel
authors.forename: K K
authors.initials: KK
authors.lastname: Mäkinen
authors.forename: C B
authors.initials: CB
authors.lastname: Bennett
authors.forename: P J
authors.initials: PJ
authors.lastname: Isokangas
authors.forename: K P
authors.initials: KP
authors.lastname: Isotupa
authors.forename: H R
authors.initials: HR
authors.lastname: Pape
authors.forename: R J
authors.initials: RJ
authors.lastname: Lamont
authors.forename: T A
authors.initials: TA
authors.lastname: DeRouen
authors.forename: S
authors.initials: S
authors.lastname: Davis
mesh_terms: D002648:Child; D003731:Dental Caries / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000382:microbiology*; D003762:Dental Instruments / Q000009:adverse effects*; D004866:Equipment Contamination; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008963:Molar / Q000382:microbiology; D012044:Regression Analysis; D018570:Risk Assessment