Dental caries experience in relation to salivary findings and molecular identification of S. mutans and S. sobrinus in subjects with Down syndrome

Abstract

This study investigated the association between clinical and salivary or molecular parameters in Down syndrome subjects. Sixty individuals (1- to 48-year old) were clinically examined using DMFT/DMFS. Stimulated saliva was collected; salivary flow was calculated (mL/min), buffering capacity was measured using a standard pH tape. In addition, 25 μL of saliva was diluted using 10-fold-dilution method and then placed on Mitis-Salivarius-Bacitracin agar to count colony forming units (CFU/mL) of mutans streptococci. Polymerase chain reaction analysis identified species. Caries indexes were 0.65-13.5 (DMFT) and 0.65-26.0 (DMFS) according to groups. Ninety-four percent of subjects had low flow rate (0.7-1.0 mL/min) and 44% had low buffering capacity (pH < 4). Besides, 60% had more than 1 × 10(6) CFU/mL, 60% had S. mutans, and 41.4% had S. sobrinus. Caries indexes did not significantly correlate with flow rate, buffering capacity, CFU/mL by Pearson's correlation (p > 0.05), and showed no significant association with prevalence of species by Chi-square (p > 0.05). There is no association between clinical picture and salivary or molecular parameters in Down syndrome subjects.

Five-year longitudinal study of dental caries risk associated with <i>Streptococcus mutans</i> and <i>Streptococcus sobrinus</i> in individuals with intellectual disabilities

“…mutans and S. sobrinus are the most commonly isolated bacterial species associated with dental caries and are regarded as the main pathogenic microorganisms of the disease (10,11,14,15). The present findings show that the prevalence of mutans streptococci was 94.5% in subjects aged 11-36 years, which is consistent with the findings of a previous study of Down syndrome patients aged 1-48 years (29). However, other studies have reported lower prevalence rates for mutans streptococci in children (13,20,27,39).…”

“…To further investigate the association between these pathogens and dental caries, quantification of bacterial proportions is essential. However, few longitudinal studies have examined the relation between these pathogens and caries incidence in general populations (25,27), and even fewer have investigated individuals with ID (28,29). Detection of these organisms is essential for dental caries prediction and subsequent treatment (22).…”

Salivary density of Streptococcus mutans and Streptococcus sobrinus and dental caries in children and adolescents with Down syndrome

“…The S. mutans ’ results corroborate the findings of previous studies 7,11,18 . However, other studies have reported similar 9 or higher counts 17 .…”

“…However, the relationship between oral streptococci and dental caries in children with DS is not well characterized. While some studies have shown that the occurrence of dental caries is associated with S. mutans counts in children and adolescents with DS 2,9,20,28 , other authors have not found such association 7 . Thus, investigations to clarify the ecologies of the oral cavities of individuals with DS are necessary 7 .…”

“…Some studies have addressed the etiology of this low prevalence of dental caries, but the exact mechanism remains unclear. Some of the hypotheses suggested to explain the low prevalence of dental caries include the following: delayed tooth eruption in combination with an altered chronology of eruption; the high frequency of hypodontia; differences in the composition, pH, and buffering capacity of the saliva and the salivary flow 8,9,25 , and differences in the cariogenic microbiota 7,9,28 .…”