The Microbiology of Primary Dental Caries in Humans

Abstract

A systematic literature review from 1966 to 2000 revealed 2,730 English-language publications on the role of bacteria in human primary dental caries in vivo. The most pertinent 313 papers were analyzed in evidence tables accessible online (http:// www.nidcr.nih.gov). The search targeted all bacterial types implicated previously in caries and asked two questions. First, what is the association of specific bacteria with tooth decay and can causation be attributed to any of those bacteria? Retrieved studies were categorized as randomized-blinded-interventional, longitudinal, case-control, and cross-sectional and were weighted in descending order in terms of significance. Although many studies, due to ethical requirements, had confounding variables, they still indicate strongly: 1) the central role of the mutans streptococci in initiation of caries of smooth surfaces and fissures of crowns of teeth and suggests their potent role in induction of root surface caries; and 2) that lactobacilli are implicated as important contributory bacteria in tooth decay, but their role in induction of lesions is not well supported. Second, what is the source of infection by cariogenic bacteria? Molecular/genetic studies of implicated bacteria isolated from humans, randomizedblinded-interventional, and longitudinal studies indicate that mutans streptococci are spread vertically among humans, mostly from mothers to their children. Implications of these conclusions are briefly discussed. The most significant problems of literature interpretation include the benefits/shortcomings of salivary and plaque monitoring of the flora, the role of sugar(s) in decay as it influences the flora, and modeling strategies to predict lesion score increments as distinct from determination of the etiological role of specific bacteria. Future directions for microbiological clinical caries research are suggested, and the use of the term "caries" to describe the disease, not its lesions, is urged.

Distribution of selected cariogenic bacteria in five different intra‐oral habitats in young children

“…Lactobacilli have been found mostly together with S. mutans in plaque and saliva because they have poor adhesive capability and similar dietary needs as S. mutans 23,24 . Lactobacilli have been also implicated with the persons having a diet rich in sugar and deep caries and/or large restorations 3 . Therefore, it is not surprising that the children in this study had L. acidophilus , on average, in all sample locations, although in somewhat low proportions, because more than two‐thirds of them had carious lesions or restored caries.…”

“…Both dental caries and periodontal disease comprise multi‐factorial diseases in which the oral microorganisms play a key role. In caries, the major suspect organisms are mainly Streptococcus mutans , Streptococcus sobrinus , and lactobacilli species 1–3 . These diseases require colonization by aetiological pathogens before their occurrence.…”

Effect of high‐fructose corn syrup on the acidogenicity, adherence and biofilm formation of Streptococcus mutans

“…Thus, cariogenic bacteria and carbohydrates in foods are pivotal factors in the process of caries. Streptococcus mutans ( S. mutans ) is regarded as a primary aetiological agent in the pathogenesis of dental caries even though additional microorganisms may be involved . Sucrose is recognized as the most caries‐promoting carbohydrate because it dramatically increases the efficiency of S. mutans adhesion and accumulation within plaque.…”

Real-time quantitative polymerase chain reaction for enumeration of Streptococcus mutans from oral samples

“…In that bacteria are required but many of these factors influence the process, dental caries is considered to be a conditional dieto‐bacterial disease (1,2). Among over 600 identifiable bacterial species in the human oral cavity, the mutans streptococci are thought to play a major microbiologic role in the initiation of dental caries (3–7). Many studies have been carried out to identify the relationship between dental caries and the timing of the initial colonization of the oral cavity as well as between dental caries and the burden of infection with mutans streptococci (8–11).…”