Increased Risk of Dental Caries Associated with Lead Poisoning

Dental caries, commonly termed tooth decay, is an infection of a tooth surface by carbohydrate-eating, acid-producing bacteria; the acid eats away at the tooth, creating a cavity of decaying tooth. 

Lead poisoning increases the risk of dental caries by:

  • weakening tooth enamel development

  • inhibiting the flow rate of and production of saliva 

  • interfering with fluoride activity and enhancing tooth demineralization 

Enamel

Enamel, the hardest substance in the body, forms the protective outer layer over the surface of baby and permanent teeth. Chemically, enamel is composed primarily of calcium phosphate and some fluoride. In the presence of sugar-eating bacteria, organic acids are produced which cause tooth demineralization, or the loss of calcium phosphate and fluoride from the enamel. This results in weakening the structure of the tooth and making the tooth more prone to dental caries.

Ideally, demineralization is balanced by remineralization, where the calcium, phosphate, and fluoride are replaced, thereby restoring the enamel as a strong protective outer layer of the tooth. 

Lead will replace calcium in enamel and become incorporated into the enamel of developing teeth resulting in a thin, defective enamel (the condition is termed, enamel hypoplasia); such teeth are susceptible to dental caries. The visual signs of enamel thinning include white spots, pits, and grooves on the outer surface of teeth.

Saliva

Saliva is produced by the three major pairs of salivary glands and multiple minor glands in the oral cavity. Saliva has many functions, including aiding to decrease the risk of dental caries. Chemically, saliva is a heavily saturated solution of calcium and phosphate which functions to neutralize acids, thereby protecting teeth from excessive demineralization and is a prime factor in reducing dental caries. In addition to chemically protecting teeth, saliva physically protects teeth through the clearance of food debris and particles. 

Lead interferes with the development of the salivary glands and with their normal functioning. The diminished flow of saliva directly increases the risk of dental caries.

Fluoride

Fluoride is a key ion in maintaining a strong enamel. Fluoride has antimicrobial activity towards oral bacteria that cause dental caries and plays a role in tipping the ratio of demineralization /remineralization towards remineralization. 

Lead interferes with the bioavailability of fluoride by binding to fluoride ions in saliva, thereby reducing the preventative capacity of fluoride to remineralize enamel after acid challenge. 

Basic Suggestions for Lead-proofing Your Home

The main sources of exposure to lead effects are in your home if built prior to 1978 and in your drinking water. Recognizing the potent harmfulness of lead to the nervous system and the hypersensitivity of children to lead, the federal government outlawed the use of lead-painted paints in 1978.

If you live in such a house, even if the walls were painted multiple times, the lead is still dangerous and present when peeling. Therefore, peeling paint, paint chips, and paint dust created by home renovations are all potentially harmful.  

Suggestions to prevent lead exposures in your home

  • Limit your child’s access to peeling paint and to chewable paint chips (apparently, these have a sweet taste)

  • Regularly wet-wipe windowsills, doors, and door frames which, because of abrasion, may contain lead-contaminated dust

  • Isolate home areas undergoing renovation and repair, as these activities generate household lead-contaminated dust; wet-mop all exposed surfaces

The other major source of exposure to lead within your home may be your drinking water. Lead can enter drinking water through corrosion of plumbing materials. Lead pipes, lead fixtures, and solder are more common in homes constructed prior to 1986.  Interestingly, lead in household water is more likely derived from your plumbing than from the local water supply.

Suggestions to reduce lead exposures from your household water

  • As hot water is more likely to contain elevated levels of lead than cold water, use cold tap water for drinking, cooking, and preparing infant formula

  • Clean the faucet aerator (i.e., screen)

  • Use a water filter certified to screen for lead

Other sources of lead of particular interest to protecting children

  • Paint on children’s toys or jewelry should not be peeling, cracking or chipping

  • Avoid candies imported from countries such as Mexico, India and China and others where lead use is common

  • Avoid traditional herbal folk medications