The occlusal plane is an imaginary line or surface formed by the biting edges of your upper and lower teeth when your jaws are closed. This alignment includes the front teeth’s incisal edges and the back teeth’s chewing surfaces. It serves as a fundamental reference point for dental professionals to evaluate tooth alignment and overall oral function.
The Functional Importance of the Occlusal Plane
A properly aligned occlusal plane plays a significant role in several daily functions. One primary function is efficient mastication, or chewing. When the occlusal plane is well-aligned, chewing forces are distributed evenly across all teeth, which helps in breaking down food effectively and reduces excessive wear on individual teeth.
Beyond chewing, the occlusal plane contributes to clear speech, known as phonetics. The precise positioning of teeth along this plane influences how the tongue and lips interact with the teeth to form various sounds. Any misalignment can interfere with this interaction, potentially affecting speech clarity.
A balanced occlusal plane supports the health of the temporomandibular joints (TMJ), which connect your jaw to your skull. Proper alignment ensures that the forces generated during chewing and biting are directed favorably through these joints, helping to prevent strain and discomfort.
Signs of an Irregular Occlusal Plane
An irregular occlusal plane means the biting surfaces of your teeth do not align as they should, presenting as a tilt or unevenness. One common irregularity is a “canted” plane, where the occlusal plane appears tilted or slanted when viewed from the front, rather than being parallel to your eyes and ears. This tilt can be noticeable at an angle of 4 degrees or more to the facial midline.
A canted occlusal plane can result from various factors, including jaw alignment issues, misaligned teeth, or uneven gum lines. It can also be linked to skeletal asymmetry, which might stem from uneven bone development in the jaw, potentially due to childhood injuries to the mandible. Such an injury could disrupt growth centers in the jaw, leading to one side developing differently from the other.
Other irregularities include a “steep” or “flat” occlusal plane, which refers to the curvature of the biting surfaces. A steep posterior occlusal plane, for instance, has been correlated with a small, retruded mandible with backward rotation. These irregularities can manifest as visible symptoms like an asymmetrical smile, where one side of the mouth appears higher or lower than the other.
Functionally, an irregular occlusal plane can lead to excessive tooth wear, as some teeth bear more biting force than others. Individuals might experience difficulty chewing food evenly, or even facial muscle pain and discomfort in the jaw joints due to unbalanced forces. Dentists often use simple tools like a tongue depressor to quickly check for a canted plane by observing if it appears slanted when bitten horizontally.
Corrective Dental Procedures
Correcting an irregular occlusal plane often involves a combination of dental procedures tailored to the specific nature and severity of the misalignment. Orthodontics, using braces or clear aligners, is a common approach to gradually move teeth into their correct positions. This treatment aims to realign individual teeth and dental arches to establish a more harmonious biting relationship.
Restorative dentistry offers another pathway, particularly when issues involve the shape or size of individual teeth. Procedures like dental crowns or veneers can be used to alter the biting surfaces of teeth, effectively building up or reshaping them to contribute to a more even occlusal plane. This method helps to distribute chewing forces more uniformly across the dental arches.
For more severe skeletal discrepancies involving the jawbones themselves, orthognathic surgery, or jaw surgery, may be recommended. This surgical procedure involves repositioning the upper jaw (maxilla), lower jaw (mandible), or both, to achieve proper alignment and balance with the rest of the face. Orthognathic surgery often works in conjunction with orthodontics, with braces typically worn before and after the surgery to refine tooth positioning.