Chewing on non-food items like plastic pen caps, water bottle tops, or straws is a common habit often driven by stress, anxiety, or deep concentration. Repeatedly biting down on hard or sharp plastic materials is detrimental to overall oral health. The physical stress and chemical exposure from this habit can lead to irreversible damage to the teeth and surrounding oral structures. Understanding the specific risks is the first step toward finding safer alternatives for this oral fixation.
Direct Physical Damage to Teeth
The hard, unyielding nature of most plastics makes them abrasive foreign objects for tooth enamel. Chewing on materials like polypropylene or high-density polyethylene creates friction that contributes to dental abrasion, the physical wearing away of the enamel layer. This gradual mechanical erosion often appears as distinctive notches or grooves near the gumline where the enamel is thinnest.
Repeated, focused pressure on a small plastic object can induce microfractures in the enamel, even if the damage is not immediately visible. These tiny cracks weaken the tooth structure, making it susceptible to larger chips or complete fractures. As enamel wears down, the inner layer of the tooth, dentin, becomes exposed, leading to increased sensitivity to hot and cold temperatures.
Existing dental work, such as fillings, crowns, or porcelain veneers, is particularly vulnerable to this stress. Chewing hard plastic creates shear forces that can cause the bond between the restoration and the natural tooth to fail, resulting in chipped edges or dislodgement of the entire filling. Once the protective enamel is compromised, the risk of bacterial infiltration and subsequent decay increases. Furthermore, the sharp edges of broken plastic can scratch or cut the soft gum tissue, creating entry points for bacteria and localized infection.
Chemical Exposure and Microplastic Ingestion
Beyond the mechanical damage, chewing plastic exposes the body to a release of chemical compounds. Common plastics like polyvinyl chloride (PVC) and polycarbonates are manufactured with various additives that can leach out into the saliva. Human saliva and the warmth inside the mouth act as a solvent, increasing the rate at which these chemicals migrate from the plastic.
Among the chemicals of concern are bisphenol A (BPA) and phthalates, known as endocrine-disrupting chemicals. BPA is often used to make rigid plastics, while phthalates are included to make plastics more flexible, such as in straws or tubing. These compounds can mimic or interfere with the body’s natural hormones, and exposure has been linked to various health issues, including reproductive and metabolic concerns.
The physical act of chewing causes the plastic to fragment into microscopic particles. These microplastics, defined as pieces less than five millimeters in size, are inevitably ingested along with saliva. Studies demonstrate that hundreds to thousands of microplastic fragments can be released per gram during chewing, introducing plastic polymers like polyethylene and polyethylene terephthalate into the digestive system.
Broader Consequences for Oral Structures
The habit of chewing plastic introduces repetitive strain on the entire oral system, extending damage beyond the teeth. The temporomandibular joints (TMJ), which connect the jawbone to the skull, are not designed for the sustained clenching and grinding that chewing hard objects demands. This can lead to temporomandibular joint dysfunction (TMD), characterized by jaw pain, headaches, clicking or popping sounds, and difficulty opening or closing the mouth.
The muscles of mastication, responsible for moving the jaw, can suffer from chronic overexertion. The continuous chewing motion causes muscle fatigue and tension, which may manifest as persistent facial or neck pain. Consistently applying force to a small area can potentially affect the alignment of the teeth, causing them to shift or leading to an uneven bite. This muscular imbalance and joint stress are problematic for individuals already prone to clenching or grinding their teeth.
Understanding and Stopping the Chewing Habit
The compulsion to chew on plastic items is often a manifestation of an oral sensory need, frequently linked to anxiety, stress, or the need for focus. The rhythmic action provides a self-soothing mechanism, helping to regulate emotions and improve concentration. Recognizing the underlying behavioral reason is the first step toward replacing the damaging habit with a safe one.
Safe Chewing Alternatives
A highly recommended alternative is sugar-free gum, which satisfies the need to chew while promoting saliva flow to neutralize acids and protect enamel. For those who require a firmer, more durable texture, specialized chewable tools, often called “chewelry,” are available. These products are made from medical-grade, non-toxic silicone and offer a safe, hygienic outlet for intense chewing needs.
Behavioral Strategies
If the habit is deeply ingrained or linked to significant underlying anxiety, consulting a medical professional or therapist can provide personalized coping strategies and behavioral modifications. Simple environmental changes, like keeping the hands busy with a fidget item or drinking water, can also reduce the impulse to put plastic objects in the mouth.