An overbite is a common type of malocclusion where the upper front teeth overlap the lower front teeth when the jaw is closed. This excessive vertical overlap affects the function and health of the mouth, not just appearance. An existing overbite can definitely get worse over time due to a combination of natural processes and harmful habits.
What Exactly Is an Overbite
The term “overbite” specifically describes the vertical measure of overlap between the upper and lower front teeth. This is technically known as a deep bite when the upper teeth cover too much of the lower teeth. It is distinct from an “overjet,” which measures the horizontal protrusion of the upper teeth forward of the lower teeth.
A bite is considered normal when the upper front teeth cover approximately 20 to 40 percent of the lower front teeth, corresponding to 2 to 4 millimeters of vertical overlap. Overlap significantly exceeding this range is classified as an excessive overbite or deep bite, which can lead to functional problems.
Progression is measured by an increase in this vertical overlap, often assessed by the percentage of the lower tooth height that becomes obscured. Severity ranges from mild overlap to severe, where the upper teeth completely obscure the lower teeth.
Habits and Factors That Increase Severity
Several factors contribute to the deterioration of an existing overbite through constant, subtle forces exerted on the dental structure. One unavoidable factor is the natural aging process, which causes slight changes in jawbone density and tooth position over decades. Teeth naturally shift due to wear and bone loss, potentially making a pre-existing overbite more pronounced.
Chronic oral habits apply sustained pressure that physically pushes teeth out of alignment, increasing overlap. Habits like lip biting or nail-biting involve repetitive contact that forces upper incisors forward or drives lower teeth backward. Tongue thrusting, where the tongue pushes against the front teeth during swallowing, can also gradually worsen the protrusion and vertical mismatch of the bite.
Bruxism, the unconscious clenching or grinding of teeth, is a significant mechanical factor that accelerates the problem. This chronic grinding causes premature and excessive wear on the chewing surfaces, particularly the lower incisors. As the lower teeth shorten, the upper teeth overlap them more significantly, effectively deepening the bite over time.
The absence of teeth also disrupts the delicate balance of the bite, leading to further misalignment. When a tooth is lost and not replaced, adjacent teeth drift into the gap, altering the overall bite structure. This shifting changes the relationship between the upper and lower jaws, which may exacerbate the pre-existing overbite by removing necessary support.
Physical and Health Effects of Progression
The mechanical forces involved in a worsening overbite create a cycle of damage impacting the teeth, gums, and jaw joint. Accelerated tooth wear is a common consequence, as excessive overlap causes the upper and lower teeth to grind against each other more severely. This friction leads to chipping, cracking, and the erosion of protective enamel, increasing sensitivity and the risk of decay.
As the vertical overlap increases, a deeper bite poses a significant risk of trauma to the soft tissues. The lower front teeth can bite directly into the gum tissue behind the upper front teeth, known as palate trauma. This chronic irritation leads to inflammation, gum recession, and tissue damage, compromising the long-term health of supporting structures.
A misaligned and progressing bite places considerable strain on the temporomandibular joint (TMJ) and its surrounding muscles. The jaw is forced into an unnatural position to compensate for bite disharmony, leading to muscle fatigue and joint stress. This can manifest as chronic pain, clicking or popping sounds in the jaw, headaches, and difficulty chewing.
Severe progression can also affect speech clarity and facial aesthetics. The misalignment of the front teeth may impede the proper articulation of certain sounds, altering the speech pattern. As the jaw relationship changes, the facial profile may become disproportionate.