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Ronald J Billings

Publications and source records attributed to Ronald J Billings.

2 recordsLinked to original sources
PubMed2004

A longitudinal study of caries onset in initially caries-free children and baseline salivary mutans streptococci levels: a Kaplan-Meier survival analysis.

OBJECTIVES: To apply survival analysis to a longitudinal study of the relationship between salivary mutans streptococci (MS) levels at baseline in initially caries-free children and caries onset in deciduous, mixed, and permanent dentition. METHODS: The Kaplan-Meier survival analysis method was used to compare survival times to caries onset for initially caries-free children with low levels of MS at baseline with survival times to caries onset for initially caries-free children with high levels of MS at baseline. RESULTS: Data from a 6-year longitudinal study of caries risk in initially caries-free children in Rochester and the Finger Lakes Region of western New York were utilized for this study. Of 464 children analyzed, 327 had a low level of MS and 137 had a high level of MS at baseline. Survival analyses showed that children with a low level of MS at baseline remained caries-free for a longer period than children with a high level of MS at baseline. Statistically significant relationships [hazard ratios (HR)] with onset of caries in deciduous, mixed and permanent teeth were found with high and low levels of salivary MS. CONCLUSIONS: Based on our analysis, we concluded that children who were caries-free at baseline and who had high salivary MS levels at baseline would be at greater risk, i.e. more susceptible to caries onset, at any given time than caries-free children who had low salivary MS levels at baseline. Survival functions for deciduous, mixed and permanent dentitions with their 95% confidence limits have been calculated. Survival analysis for the exploration of longitudinal caries studies has an advantage over traditional statistical methods, as it takes into account censored observations and incorporates the concept of risk over time. Hence, survival analysis is well suited for studying transitions from one health state to another, in this case, from a caries-free state to a caries-active state.

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PubMed2004

Teeth.

Common environmental chemicals, drugs, or physical agents can adversely affect human teeth during their embryonic development and after their eruption into the oral cavity. One of the more common elemental toxicants is lead. Teeth are known to accumulate lead during their development. Both animal and human studies have shown that teeth with high lead levels are generally more susceptible to dental caries. Similarly, although inorganic fluorides have long been recognized for their potential to prevent dental caries, exposure to excessive amounts of fluoride when enamel is forming often leads to a type of enamel hypoplasia referred to as dental fluorosis or mottled enamel. Teratogenic agents, such as tetracyclines, a class of antibiotic drugs commonly administered to infants and children, will often result in the discoloration of tooth enamel when prescribed during tooth development. It has recently been suggested that childhood exposure to passive smoking increases the risk for dental caries. Environmental tobacco smoke has previously been linked to periodontal disease in adults. However, this is the first report of an association between passive tobacco smoke and increased susceptibility to dental caries. Last, an often-overlooked source of damage to teeth among all age groups after their eruption into the oral cavity is physical trauma from a variety of sources, especially sports-related injuries. Epidemiologic data suggest that up to one third of all dental injuries are sports related.

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