Bacterial composition in the supragingival plaques of children with and without dental caries

Abstract

Purpose: The purpose of the present investigation was to determine if the supragingival bacterial composition plaques in children with caries would differ from those found in caries-free controls.

Material and methods: Pooled supragingival plaque samples from the smooth surfaces of teeth were collected from 75 children with caries and 131 children without caries. The plaque samples were analysed for bacterial content by cultures on a series of non-selective and selective media for aerobic, microaerophilic and anaerobic bacteria. Additionally, the specimens of dentine carious lesions were examined. The standard culture procedures and identifications of bacteria were used.

Results: Among 131 children without dental caries, 41 (31.3%) were at preschool age with deciduous teeth and 90 (68.7%) at school age with permanent teeth. Dental plaques of caries-free children revealed 452 strains, out of which 326 (72.1%) were from permanent teeth, 126 (27.9%)--from deciduous teeth (p = 0.0001). Among 75 children with dental caries, 61 (81.3%) were at preschool age and 14 (18.7%)--at school age. There were 239 strains isolated from supragingival plaques in children with dental caries, 187 (78.2%) --in preschool children, and 52 (21.8%)--in school children (p < 0.05). From dentine carious lesions in these children, 209 strains were isolated; 164 from preschool children and 45--from school children (p < 0.05). Gram-positive bacteria were isolated more frequently than Gram-negative ones (p = 0.0001) from supragingival plaques both in children with and without dental caries. Streptococcus genus bacteria were isolated more often (p = 0.0002) from the plaques in school children without dental caries. The proportion (%) of aerobic and anaerobic bacteria was comparable (p > 0.05) in dental plaques in children with and without dental caries, except for Veillonella spp., which were isolated more frequently from dental plaques in school children with dental caries (p = 0.01).

Conclusions: 1) Generally, there was no statistically significant difference of bacterial species composition isolated from supragingival plaques in children with deciduous and permanent dental caries and caries-free children. 2) There was no difference between bacterial composition in dentine carious lesions of deciduous teeth and permanent teeth as compared to supragingival plaques in these children (except for Neisseria spp., Peptostreptococcus spp.).