Dental occlusion describes the way your upper and lower teeth meet when your mouth closes. When the teeth and dental arches align properly, the top teeth rest slightly over the bottom teeth, allowing for comfortable chewing and speaking. Misalignment, known as malocclusion, is a common condition that can cause functional issues beyond appearance, such as chronic headaches, difficulty chewing, and excessive wear on tooth enamel. Addressing these issues requires professional intervention, which can range from repositioning teeth to realigning the jawbones themselves.
Identifying and Classifying Jaw Misalignment
A dental professional first determines the extent of a misalignment by assessing the size and shape of the teeth and the skeletal structure of the jaws. The most widely used system for describing malocclusion is the Angle classification, which focuses on the relationship between the upper and lower first permanent molars. Class I malocclusion is the most frequent, where the molar relationship is normal, but the issue lies with dental irregularities like crowding, spacing, or rotations.
Class II malocclusion involves an overbite, where the upper jaw or teeth protrude significantly forward relative to the lower jaw. Conversely, a Class III malocclusion presents as an underbite, with the lower jaw or teeth positioned forward of the upper jaw. Misalignment can result from genetic factors influencing jaw size, early loss of baby teeth, or childhood habits such as thumb-sucking or prolonged pacifier use.
Orthodontic Approaches for Correction
For most cases of malocclusion, the primary method of correction involves orthodontics, which focuses on repositioning the teeth within the dental arches. Traditional metal or ceramic braces use brackets bonded to the tooth surface that act as handles for a thin archwire. This archwire runs through the brackets, applying a gentle, constant force to the teeth. The sustained pressure stimulates the periodontal ligament and triggers bone remodeling, allowing the tooth to move safely.
Clear aligners offer a less visible alternative, using a series of custom-made, transparent plastic trays to achieve movement. Each sequential aligner is designed to move the teeth incrementally, typically by only 0.2 to 0.3 millimeters per tray. Small, tooth-colored resin bumps called attachments are often bonded to certain teeth to give the aligner a better grip, which is necessary for more complex movements like rotation or intrusion. Patient compliance is important, as aligners must be worn for 20 to 22 hours per day to ensure the planned movement sequence is completed successfully.
For younger patients whose jaws are still developing, specialized auxiliary appliances are used to modify skeletal growth. A palatal expander, for example, is fixed to the upper molars and uses a screw mechanism to gradually widen the upper jaw. This is done by gently separating the mid-palatal suture, which is still flexible during childhood, creating necessary space to prevent crowding and correct a crossbite. Other devices, such as functional appliances or headgear, can be used to guide the growth of the lower jaw forward or backward to address developing Class II or Class III discrepancies.
When Surgical Intervention is Necessary
When a jaw misalignment stems from a severe mismatch in the size or position of the upper and lower jawbones, orthodontic treatment alone is insufficient. It often requires a combined approach involving orthodontics and orthognathic surgery. Jaw surgery is reserved for cases where the bite issue is too pronounced to be corrected by moving teeth alone, such as severe underbites, open bites, or facial asymmetry. The surgical procedure is performed after the patient’s jaw growth has stopped, which is generally around age 16 for females and 18 for males.
The process usually begins with pre-surgical orthodontics, where teeth are aligned within their respective arches to ensure they will fit together correctly after the jaw is repositioned. During the surgery, an oral and maxillofacial surgeon carefully cuts and repositions the jawbones to establish the proper bite relationship. The newly aligned bones are then secured with small metal plates and screws to stabilize the structures while they heal. This treatment is designed to restore both proper function, such as chewing and breathing, and facial balance.
Maintaining Jaw Alignment Post-Treatment
Once the active phase of treatment is complete, the retention phase begins to maintain the newly achieved alignment. The tissues and bone surrounding the moved teeth need time to adapt and stabilize in their new positions, and without retention, the teeth have a natural tendency to shift back. Retainers are custom-made appliances that hold the teeth in place while the surrounding bone and soft tissues remodel and solidify.
Retention devices include fixed retainers, which are thin wires bonded permanently to the tongue-side of the front teeth, and removable retainers. Removable options include clear, vacuum-formed trays or the Hawley retainer, which uses an acrylic plate and a metal wire. Consistent wear, often full-time initially followed by nightly use, is necessary to prevent minor shifts that can affect the bite. Long-term stability is also supported by avoiding habits that place unnecessary stress on the jaw, such as teeth grinding or clenching.