The sensation of teeth striking each other prematurely while chewing, or when the mouth is closed, is medically termed occlusal interference or premature contact. This abnormal event occurs when specific teeth meet before the entire dental arch achieves a stable, simultaneous bite. These contacts disrupt the harmonious relationship between the upper and lower teeth, often forcing the jaw to shift to find a comfortable resting position. Ignoring this phenomenon can lead to negative consequences, including accelerated tooth wear, fractures in dental work, chronic jaw pain, and increased tooth sensitivity. Understanding the underlying cause is the first step, as interference can stem from long-term issues in tooth structure, recent dental changes, or problems with the jaw’s mechanics.
Causes Related to Static Tooth Position
Occlusal interference can often be traced back to the physical, static arrangement of the teeth, known as malocclusion. Malocclusion is a fundamental misalignment where the upper and lower teeth do not fit together correctly when the mouth is closed. These structural issues cause teeth to follow an improper, deflecting path during closure, resulting in an unintended clash.
Specific alignment problems, such as overbites, underbites, or crossbites, mean the relationship between the dental arches is incorrect, creating uneven pressure points. For instance, an underbite may cause the lower teeth to protrude and strike the upper teeth. Tooth shifting is another common factor, especially following the extraction of a tooth years earlier. Adjacent teeth can drift or tilt into the empty space, altering the biting surface and creating new, high contact points that interfere with chewing. Furthermore, if the natural wear patterns of teeth are uneven or excessive, it can introduce deflective occlusal interferences in both the static and dynamic phases of the bite.
Interference Due to Recent Dental Procedures
A common and often easily corrected cause of sudden interference is the introduction of new dental materials. When a new filling, crown, veneer, or bridge is placed, it must be perfectly contoured to match the height and shape of the surrounding teeth and the opposing arch. If the restoration is slightly “high,” meaning it extends above the natural tooth surface, it will be the first point of contact when the patient bites down.
This premature contact, also called iatrogenic interference, applies disproportionate pressure to that specific tooth and the opposing one, disrupting the overall alignment. Dentists typically perform “occlusal adjustment” immediately after the procedure, using articulating paper to mark high spots for selective reshaping. However, because the mouth is often numb, a small high spot can sometimes be missed, leading to clashing teeth once the anesthesia wears off. Even a recent tooth extraction can cause a subtle change, as the loss of a tooth allows remaining teeth to shift slightly, changing the chewing path and creating a minor malalignment.
The Role of Jaw Mechanics and Muscle Tension
The problem of clashing teeth does not always originate with the teeth themselves, but with the complex system that moves the jaw: the temporomandibular joints (TMJ) and the muscles of mastication. Dysfunction in the TMJ (TMD) involves misalignment or inflammation of the joint connecting the jawbone to the skull, which alters the jaw’s pivot and closing trajectory. When the jaw’s movement is irregular, the teeth may not meet in their intended position, leading to premature contacts during the chewing cycle.
A significant contributor to bite interference is bruxism, which is the habitual grinding or clenching of the teeth. Bruxism subjects the teeth to extreme, non-functional forces, leading to rapid and uneven wear of the enamel and creating new contact points that disrupt a smooth bite. Constant clenching can also cause the jaw muscles—the masseter and temporalis—to become fatigued and spasm, pulling the jaw slightly off-center and forcing the teeth to clash. This muscle tension is often linked to stress and anxiety, creating a cycle where occlusal interference aggravates muscle tension, which then worsens the bite alignment.
Professional Diagnosis and Correction Methods
Identifying the exact source of occlusal interference begins with a comprehensive clinical examination by a dental professional, often involving a detailed patient history regarding pain and recent procedures. Dentists use thin, colored articulating paper, which leaves marks on the teeth to highlight premature or high contact points. For more complex cases involving jaw movement, the dentist may use instrumental methods like a T-Scan system, which digitally measures the timing and force of occlusal contacts, or take impressions to mount the teeth on an articulator to study the bite outside the mouth.
Once the cause is determined, treatment is tailored to the specific problem. For minor interferences caused by new dental work, the dentist performs occlusal equilibration, or “selective grinding,” which involves reshaping the interfering surface of the tooth or restoration to restore harmonious contact. For structural misalignment problems, the solution may involve orthodontic alignment using braces or clear aligners to physically move the teeth into a proper relationship. If the interference is caused by bruxism or TMD, a custom-fitted night guard or occlusal splint may be prescribed to protect the teeth from grinding forces and stabilize the jaw joint, relaxing the hyperactive muscles.