Biology, immunology, and cariogenicity of Streptococcus mutans

Oral bacterial levels of 46 mother-child pairs were monitored from infant birth up to five years of age so that the acquisition of mutans streptococci (MS) by children could be studied. The initial acquisition of MS occurred in 38 children at the median age of 26 months during a discrete period we designated as the "window of infectivity". MS remained undetected in eight children (17%) until the end of the study period (median age of 56 mo). The levels of both MS and lactobacilli in saliva of mothers of children with and without MS were not significantly different. Comparisons between a caries-active cohort colonized by MS (nine of 38) and children without detectable MS revealed similar histories in terms of antibiotic usage, gestational age, and birth weight. Interestingly, half of the children between the ages of one and two years who were not colonized by MS were attended by caretakers other than the mother, while all of the caries-active children during this same time period were cared for by their mo...

Initial Acquisition of Mutans Streptococci by Infants: Evidence for a Discrete Window of Infectivity

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, randomized-blinded-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.

The microbiology of primary dental caries in humans.

Changes in restorative techniques and the development of newer restorative materials have allowed for the use of more conservative cavity preparations. This 10-year study evaluated bonded and sealed composite restorations placed directly over frank cavitated lesions extending into dentin vs. sealed conservative amalgam restorations and conventional unsealed amalgam restorations. The results indicate that both types of sealed restorations exhibited superior clinical performance and longevity compared with unsealed amalgam restorations. Also, the bonded and sealed composite restorations placed over the frank cavitated lesions arrested the clinical progress of these lesions for 10 years.

Ultraconservative and cariostatic sealed restorations: results at year 10

Clinical studies have shown that oral tissues can be affected by pregnancy. Pregnancy-related changes are most frequent and most marked in gingival tissue. Pregnancy does not cause gingivitis, but ...

Effect of pregnancy on periodontal and dental health

Preventive measures in mothers influence the establishment of the bacterium Streptococcus mutans in their infants

— The number of S. mutans (S.m.) in saliva of parents and their children was studied. Thirty-six children, 4 1/2–5 years old, and their parents participated. A quantitative correlation was found between the number of S.m. in the mothers and their children. The degree of infection also seemed to reflect the caries experience of the child. When adults with different levels of S.m. in saliva contaminated metal spoons with saliva, a correlation between the salivary count of S.m. and the number of microorganisms transferred to the spoon was found. The survival of S.m. on saliva-contaminated test-plates was tested. After 7 h the number of viable S.m. had decreased considerably but a few cells could be found after 24–48 h. To study the presence of S.m. on objects in the city often touched by hands, MSB-containing agar dishes were pressed against several objects such as doorhandles. Only four out of 24 objects were found to be contaminated by S.m.

Intrafamilial levels of Streptococcus mutans and some aspects of the bacterial transmission.

— S. mutans, S. salivarius, S. mitis and S. sanguis strains were isolated from three subjects of blood groups A, B and O. Parotid saliva samples obtained from the same subjects induced aggregation of some of the bacteria, the S. sanguis and the S. mutans strains in particular. While parotid saliva from the three subjects gave almost identical reactions, slight interindividual differences were observed for a few strains with the submandibular sublingual salivas. In parotid saliva, secretory antibodies reacting with all strains were present. The antibody levels differed between the three subjects but no specific pattern was observed when homologous strains were compared with heterologous strains.

Douglas Bratthall

Papers

Preventive measures in mothers influence the establishment of the bacterium Streptococcus mutans in their infants

Intrafamilial levels of Streptococcus mutans and some aspects of the bacterial transmission.

Salivary agglutinin and secretory IgA reactions with oral streptococci.