Prediction of caries development for molar fissures with semiquantitative mutans streptococci tests

Risk-specific caries prevention requires validated and simple parameters fo r a caries risk assessment. The aim of the study was to evaluate the validi ty of a site-specific chair-side mutans streptococci (MS) test for the pred iction of caries incidence in fissures. In 230 6- to 7-yr-old children, occ lusal plaque samples of teeth 16 and 36 were cultured with Dentocult SM(R) tests at 37 degrees C for 24 hr. Caries (DMFS), initial caries, sealants, a nd a plaque index (QHI) were recorded and oral hygiene habits were assessed . Not erupted, carious, filled and sealed teeth were excluded from the anal ysis (n=154). After 2 yr, the status of the fissures was re-examined, and a fluoride history was recorded with a questionnaire filled out by the child ren's parents. Sealed teeth were excluded again (n=54). With a classificati on of MS score 0 or 1 as low and MS score 2 or 3 as high caries risk, 92% a greement was reached by two independently working examiners. The MS scores and caries incidence correlated significantly. Seventy-eight % of the carie s progression in fissures was prognosed correctly. Sensitivity was 50%, spe cificity 82%, positive predictive value 29%, and negative predictive value 92%. Children with caries progession tended to have lower fluoride scores. Low MS scores were most likely to be associated with low caries incidence, while high mutans streptococcci scores seem to be partially compensated by other parameters.