Oral Health

Oral health conditions include a number of congenital or developmental anomalies, such as clefts and tumors. But the most common oral health problem is tooth decay, known medically as dental caries. Although dental caries is largely preventable, more than half of all adults above age 18 present early signs of this disease and, at some point in life, about three out of four adults will develop the disease. In older adults, tooth decay and periodontal disease are the leading causes of tooth loss. Tooth decay is also common among children as young as 5 years and remains the most common chronic disease of children aged 5 to 17 years. It is estimated that tooth decay is four times more prevalent than asthma in childhood. Poor oral health has been related to decreased school performance, poor social relationships, and less success later in life. It is estimated that about 51 million school hours per year are lost in the United States alone because of dentalrelated illness. In adults, dental caries and, eventually, tooth loss can reduce chewing ability that leads to detrimental changes in food selection. This, in turn, may increase the risk of particular systemic diseases such as cardiovascular diseases.

Despite numerous epidemiologic studies currently available to assess the pattern of dental caries in oral health, there are still some fundamental questions that remain unanswered. As an example, many dentists believe that there are spatial symmetries in the mouth with respect to caries development, but this has never been demonstrated statistically. Although many dental studies provide detailed tooth-level data on caries activity, most analyses still rely on the decayed, missing, and filled (DMF) index introduced in the 1930s. This approach operates at the mouth level, that is, it counts the number of decayed teeth within a person's mouth without including information on which specific teeth are decayed; therefore, it may not be relevant in assessing the spatial distribution of the dental caries in a mouth. A more useful way to study oral health may be to collect data at the tooth level. Models that summarize tooth-level data can be used to answer questions related to tooth surface susceptibility to caries experience, symmetries in the mouth with respect to dental caries, and differences in surface susceptibility according to caries risk groups. Use of tooth-level models should improve our ability to analyze and interpret complex dependent data generated from clinical trials and epidemiologic studies in dental research.