A COMPARISON OF THE MICROBIAL-FLORA IN CARIOUS DENTIN OF CLINICALLY DETECTABLE AND UNDETECTABLE OCCLUSAL LESIONS

It is not known whether the aetiology of occlusal hidden caries lesion s (HCL) is identical to that of small visible lesions (SVL). Previous studies ofthe microflora of HCL suggest that relatively few species ca n be isolated. The aim ofthe present study was to compare the bacteria l composition of dentine from 10 HCL and 17 SVL in a population of chi ldren aged 8-18 years. The following bacteria were identified: Actinom yces spp., mutans streptococci, Streptococcus sanguis, Streptococcus o ralis, Streptococcus gordonii, Streptococcus mitis, and Lactobacillus spp. Streptococcus mutans was found more often in the HCL group (p = 0 .03), while Streptococcus sobrinus was found more often in the SVL gro up (p = 0.05). However, proportions ofboth species were lower in the S VL group as compared with the HCL group (S. mzltnns p = 0.07; S. sobri nus p = 0.03). Lactobacilli and Actinomyces spp. were found at similar levels in bath groups. A more diverse range of streptococcal species and Veillonella was found in the SVL group (p = 0.001). These results show a less complex microflora in HCL as compared with SVL, indicatin, o that the aetiology ofhidden caries might be different from thatofope ncaries.