Chewing gum is a soft substance designed for repetitive chewing. This product has a complex relationship with oral health. Depending on its ingredients and usage, chewing gum can either benefit teeth or cause potential harm. Its effects range from mechanically stimulating protective responses to altering the mouth’s biological environment.
The Primary Action: Stimulating Saliva Flow
The most immediate effect of chewing gum is the mechanical stimulation of salivary glands. The act of chewing dramatically increases the rate of saliva production, sometimes by as much as 10 to 12 times the resting rate. This increased flow is a fundamental protective mechanism for the teeth and gums.
Saliva acts as a natural rinsing agent, washing away food debris and sugars after a meal. It contains bicarbonate, a powerful buffer that neutralizes acids produced by oral bacteria. This neutralization is important because a highly acidic environment (pH 5.5 or lower) causes the demineralization and erosion of tooth enamel.
Saliva is also saturated with minerals like calcium and phosphate, which are necessary for the remineralization of tooth enamel. When enamel is weakened by acid attacks, these minerals are redeposited onto the tooth surface, helping to repair and strengthen the enamel. By stimulating a higher volume of saliva, chewing gum enhances this natural repair process, especially when chewed for about 20 minutes after eating.
Chemical Differences: Sugar, Xylitol, and Acid Neutralization
The chemical composition of the gum, particularly its sweetener, determines the overall effect on teeth. Gum containing sugar, such as sucrose, provides a direct food source for Streptococcus mutans, the primary bacteria responsible for tooth decay. When these bacteria metabolize sugar, they rapidly produce acids that cause the pH to drop, leading to enamel erosion and cavity formation. This acid production often outweighs the benefit of increased saliva flow, making sugary gum detrimental to dental health.
Sugar-free gums use non-fermentable sweeteners like sorbitol, maltitol, or xylitol, which oral bacteria cannot process into acid. This lack of acid production is the major benefit of sugar-free gum, helping maintain a neutral or higher pH level in the mouth.
Among these sugar alcohols, xylitol has a unique, active anti-cariogenic effect. Streptococcus mutans attempts to metabolize xylitol, but this process is futile, leading to a buildup of toxic compounds and the eventual death of the bacteria. Xylitol actively reduces the number of decay-causing bacteria in the mouth, sometimes by as much as 90 percent. Chewing gum with xylitol also encourages the release of bicarbonate in the saliva, which further boosts the mouth’s buffering capacity to neutralize plaque acid after meals.
Physical Consequences: Wear and Dental Hardware
Beyond chemical interactions, the physical act of chewing gum introduces mechanical stresses on oral structures. Prolonged chewing can contribute to excessive mechanical wear on tooth enamel, though this risk is low for most modern gums. The more significant physical concerns relate to existing dental work and the jaw joint.
The sticky, repetitive motion of chewing gum can pose a direct threat to dental hardware, such as fillings, crowns, and bridges. The gum’s adhesive nature and continuous pulling force can loosen restorations or completely dislodge a crown or filling. For individuals with orthodontic braces, gum is strictly discouraged because it can stick to wires and brackets, causing damage or making the appliances difficult to clean.
Excessive or prolonged gum chewing can also strain the muscles that control the jaw’s movement. This habit can lead to fatigue or exacerbate existing issues with the Temporomandibular Joint (TMJ). Symptoms of this strain include jaw pain, headaches, or a clicking and popping sensation in the joint.