Caries Process, Prevention, and Management: The Agent
Course Number: 711
Introduction
Dental caries is a very complex disease. It is arguably the most prevalent chronic disease in humans, affecting most of the dentate population at some time in their lives. In the United States, dental caries is the most common chronic disease in childhood, with 42% of children between the ages of 2 and 11 having had caries in primary teeth and 23% of children in this same age group having untreated dental caries.1 Among dentate adults aged 20 to 64, nearly 90% have caries in permanent teeth.2 Commonly termed “tooth decay,” dental caries can be defined as a biofilm-mediated dysbiosis that involves changes in the microbiome composition and function, which leads to the dissolution of tooth tissues (enamel and dentin) by acid produced by select oral bacteria, as a result of the fermentation of dietary carbohydrate.3 Clinically, it is observed the localized destruction of tooth tissues over time. These bacteria aggregate in dental plaque that forms on the outer surface of teeth. In a healthy mouth environment, the bacteria that populate plaque are harmless, but when the environment becomes acidic, the population changes to bacteria that thrive in acidity and are linked to caries. A combination of several factors and sub-factors are required for dental caries to develop, including some that are innate to the oral environment, making caries a multifactorial disease that can be difficult to manage and completely prevent. The caries process, the multiple factors that influence caries development, and plaque as a microbial biofilm ecosystem, are discussed.
Clinical Significance Snapshot
Simply put, what causes dental decay? How can I explain it to my patients?
Dental decay is caused when bacteria that accumulate on the surfaces of the teeth feed on sugars in the diet and convert the sugars into acids that then dissolve the hard tooth material. This results in the loss of minerals, which over time can result in cavities.
Nearly every mouth contains the bacteria that can cause decay. The mouth can withstand several attacks each day from the bacteria that turn sugar into acid. During times between meals, it is possible for the tooth to be repaired by the action of saliva, which contains buffers that will neutralize the acids produced by bacteria and replace the minerals that have been dissolved by the acids. Fluoride in toothpaste helps make teeth more resistant to the acid attack. It is important to clean teeth well to remove as much dental plaque as possible.
The decay process starts with the appearance of a white spot on the surface of the tooth in areas that accumulates dental plaque, i.e., close to the gum line and on the occlusal surfaces. Once sufficient mineral has been lost, the white spot turns into a cavity and it is more difficult to control the lesion progression, frequently requiring the repair of the cavity by the dentist to restore tooth function.
In most cases, caries can be controlled by good oral hygiene practices, focusing on biofilm mechanical control (toothbrushing), since the disease is caused by dysbiosis in the biofilm lead by frequent exposure to fermentable carbohydrates, especially between meals.4 Therefore, the most important action is to brush at least twice a day with a fluoride toothpaste that strengthens the enamel against acid attack, encourages remineralization, and removes the plaque biofilm. The frequency of intake of sugars should be reduced as much as possible, and, ideally, limited to mealtimes, so that acids in biofilm are only produced 3 or 4 times a day, and that there is plenty of time between meals for saliva to act by replacing any minerals that have been dissolved by the acid production during mealtimes. In addition, the presence of fluoride in toothpaste makes enamel more resistant to acid dissolution and encourages the process of remineralization.