Prevalence of Mutans Streptococci in Japanese Children with Systemic Disease

Objectives: Streptococcus mutans and S. sobrinus are associated with the development of dental caries. We detected these bacteria using a polymerase chain reaction (PCR) method, and then compared their presence and caries incidence in Japanese children with systemic disease. Methods: The subjects were 57 children with systemic disease and 57 healthy controls, aged 2-16 years old, that were matched for age and sex. Plaque samples were collected using a sterile toothbrush from all erupted tooth sites in the subjects. A dental examination was performed for dmft and DMFT using the WHO caries diagnostic criteria. Results: Mean dmft and DMFT scores for diseased children were 3.90±3.67 and 0.67±1.24, respectively, and 3.83±3.29 and 0.42±0.95, respectively, for the healthy controls. There was no significant difference in dmft and DMFT scores between the 2 groups, and mutans streptococci distribution was similar between the diseased children and healthy controls. In all subjects the prevalence of S. mutans and S. sobrinus was 45.6% and 74.6%, respectively, while 7.1% were positive for S. mutans alone, 35.5% for S. sobrinus alone, and 38.6% for both S. mutans and S. sobrinus, whereas 18.5% were negative for both S. mutans and S. sobrinus. Conclusions: Our results indicated that both diseased and healthy children exhibit similar mutans streptococci compositions and dental caries incidence.