Epidemiology and Etiology of Caries and Periodontal Disease in a U.S. Population


Dental caries, or tooth decay, results from the breakdown of the hard tissues of the tooth (enamel, dentin, and cementum) due primarily to the acid by-products of bacterial metabolism on a susceptible tooth surface. Bacteria use simple sugars as a food source and produce metabolic acids as a part of the process to break down sugars.17,18 Overall acidity within the mouth, the buffering capacity of the saliva, the hardness of tooth enamel, and available mineral content for remineralization of the hard tissues influence the rate and severity of the progression of carious lesions.13 Conditions and medications that affect salivary flow, poor tooth cleaning, dietary sugar and acid content, and fluoride availability can all affect the rate of caries.14

Within the oral cavity, the oral hard tissues constantly undergo remodeling through a demineralization-remineralization process.19 As pH within the oral cavity or at a local site drops, demineralization occurs and as the pH increased, remineralization of those tissues is seen. The net resultant mineral exchange is a determinant of caries development and progression.20 Strategies for dental caries prevention include providing access to fluoride as a component of the remineralization process, which results in an increase in acid-resistance in the resulting remineralized enamel and limiting exposure to acids from dietary, intrinsic, and extrinsic sources that may decrease pH and facilitate the demineralization process.20,21 Water fluoridation has proven to be one of the most cost-effective methods for reducing overall caries rates in the population with every $1 spent on water fluoridation returning from $5-32 in decreased healthcare costs within the community!22

Dental caries is a highly prevalent disease in both children and adults, despite declining rates of both treated and untreated caries since the 1970s. Nearly 19% of US children ages 5-19 years have untreated caries and almost 32% of US adults ages 20-44 years have untreated caries.23 The average adult has 3.28 decayed, missing, or filled teeth and tooth loss and decay are more prevalent in some groups of individuals, including: children and older adults, individuals with lower socioeconomic status, Hispanic ethnicity, and non-Hispanic blacks.23,24 Patients’ quality of life is negatively affected by poor oral health and high caries and edentulism rates with the impact being significant in both children and adults.25 Nearly 51 million school hours are lost each year to dental-related illnesses, and children from the lowest household incomes suffer 12 times more restricted-activity days than those from higher income households.26 Employed adults also lose 164 million work hours each year to dental disease.26 The emotional, financial, and educational impact of these diseases is of high importance and proper oral hygiene and home care is critical to the management and prevention of dental caries (Figure 1).

Figure 1. Caries Impact in the United States.22,113,114

Image of Caries Impact in the United States.

Periodontal Disease

Periodontal diseases include inflammatory and tissue-destructive diseases of the supporting structures around the teeth, comprised of the gingival tissues, periodontal ligament, alveolar bone, and cementum. Research shows all individuals are susceptible to gingivitis, a reversible form of gingival inflammationand may be the precursor to more serious, irreversible forms of periodontal disease. Gingivitis is caused by bacterial plaque and a susceptible host and, in most cases, the severity is related to the amount and type of bacteria present on tooth and soft tissue surfaces throughout the mouth as well as the individual patient susceptibility to disease.27,28 Removal of plaque and local etiologic factors results in the reversal of gingivitis symptoms and reduces local and systemic levels of inflammatory markers in patients with gingivitis.8,29

Periodontitis is a chronic disease of the hard and soft tissues supporting the teeth initiated by bacterial plaque, which then causes a host immuno-inflammatory response that, over time, may result in progressive destruction of the periodontal ligament and alveolar bone if not adequately resolved.30-35 The disease typically has a slow to moderate rate of disease progression, but episodes of accelerated attachment loss may be associated with local and/or systemic factors.32,33 Disease severity is classified as mild (1-2mm), moderate (3-4mm), or severe (≥ 5mm) based on the amount of clinical attachment loss (CAL).36,37 The prevalence of periodontitis has been estimated to be over 47% of U.S. adults, or 64.7 million individuals.38 Of those individuals, 8.7% showed mild disease, 30.0% demonstrated moderate disease, and 8.5% had severe chronic periodontitis.38 Risk indicators for periodontitis include male gender, Hispanic ethnicity, and lower socioeconomic status. Furthermore, cigarette smoking and uncontrolled or poorly controlled diabetes mellitus have been shown to be risk factors for periodontitis.39 Prevalence of periodontitis varied two-fold between the lowest and the highest levels of socioeconomic status (Figure 2).39

Figure 2. Periodontal Disease Prevalence in the United States.114

Image of Periodontal Disease Prevalence in the United States.

Disease progression of periodontitis has been categorized into subpopulations demonstrating rapid progression (10-15% of disease cases), moderate progression (80% of disease cases), and mild/no progression (5-10% of disease cases).38-40 The prevalence distribution of periodontal disease severity and disease progression in treated and untreated populations38-40 suggests host factors play a significant role in disease progression after bacterial initiation.41-46

Because both gingivitis and periodontitis are initiated by bacterial plaque, the removal of bacteria and their food sources from hard and soft tissues in the oral cavity is critical for the prevention, control, and management of periodontal disease.