Mutans Streptococci and Oral Health Behavior in Children and Adolescents Having Primary and Permanent Caries: A Case–Control Study

correlation between caries experience in primary teeth and caries outcome in permanent teeth. 9Many studies have investigated the correlation of oral microbiota and caries in different dentition stages using saliva as a sample. 10,11However, the tooth surface is the natural habitat for dental plaque. 12,13The levels of S. mutans in different dentition stages have not been fully explored, particularly using dental plaque samples.Recent techniques like 16S ribosomal IntroductIonDental caries is one of the most common chronic oral infectious diseases in the world. 1 Streptococcus mutans has been implicated as the major etiological agent of dental caries. 2,3The ecological plaque hypothesis states that caries result from a shift in the balance of commensal flora to acid-producing bacteria, including S. mutans, due to changes in the oral cavity environment, resulting in biofilm accumulation on the dental surface. 4Mainly, studies have reported a correlation between levels of mutans streptococci and the severity of dental caries, but a few studies have also reported a lack of correlation. 3,5Mutans streptococci are acidogens, using glucosyltransferases to metabolize sucrose, thereby increasing bacterial adhesion and biofilm accumulation on the dental surface. 6The colonization of mutans streptococci is increased with increased sugar consumption, as it decreases the pH and promotes cariogenic flora. 7Tooth brushing also modulates the level of mutans streptococci. 8Poor oral hygiene practices can be a risk factor for caries in children as well as adolescents.Considerable research has established that S. mutans is an efficient cariogenic microorganism.Recent research has shown a significant shift in oral microbiome composition from the primary to permanent dentition stage, indicating several transitions between primary and permanent dentition stages.This suggests a strong