Misaligned teeth are a common dental concern. The technical term for this condition is malocclusion, which describes a discrepancy in how the upper and lower teeth meet. This issue extends beyond cosmetic appearance, affecting overall dental health. This article defines the professional terminology, details the classifications used by orthodontists, and outlines the comprehensive options for correction.
Defining Dental Misalignment
The professional term used to describe any deviation from an ideal bite relationship is malocclusion. This term combines the Latin “mal” (bad or incorrect) and “occlusion” (the manner in which the upper and lower teeth come together). A proper, or ideal, occlusion exists when the teeth of the upper jaw (maxilla) and the lower jaw (mandible) align precisely.
In an ideal bite, the upper teeth slightly overlap the lower teeth, with the upper dental arch resting just outside the lower arch. Specifically, the mesiobuccal cusp of the upper first molar should fit into the buccal groove of the lower first molar, establishing a balanced relationship. Malocclusion represents any irregularity in this alignment, involving the relationship between the jaws, the positioning of individual teeth, or both.
Classifying Types of Misalignment
Orthodontists use a standardized system, primarily Edward Angle’s classification, which categorizes malocclusion based on the sagittal (front-to-back) relationship of the first permanent molars. This system provides a framework for diagnosing the skeletal and dental foundation of the misalignment.
Class I Malocclusion is the most common category, characterized by a normal molar relationship where the key cusps align correctly. However, the front teeth still have positional issues, such as crowding, rotations, or minor spacing.
Class II Malocclusion occurs when the lower jaw or arch is positioned too far back relative to the upper arch, often resulting in an increased horizontal overlap. This is commonly associated with an overbite, where the upper front teeth excessively overlap the lower front teeth vertically. Class II is further divided into Division 1 (protruding upper incisors) and Division 2 (retroclined upper incisors, leading to a deep vertical overlap).
Class III Malocclusion is the opposite, defined by the lower jaw or arch being positioned too far forward relative to the upper arch. This is recognized as an underbite, where the lower front teeth jut out beyond the upper front teeth. Both Class II and Class III frequently involve underlying jaw discrepancies.
Beyond Angle’s classification, misalignments are also described by specific tooth-to-tooth relationships:
- A crossbite involves one or more upper teeth biting inside the lower teeth, which can occur in the front (anterior) or the back (posterior).
- An open bite is a vertical misalignment where the upper and lower teeth do not touch when the mouth is closed, leaving a gap.
- Crowding refers to insufficient room for the teeth to align properly along the arch.
- Spacing refers to excessive room between teeth along the arch.
Understanding the Root Causes
The origin of malocclusion is often multifactorial, stemming from a combination of genetic, environmental, and dental factors. Skeletal factors represent inherited traits that govern the size and shape of the facial bones. Discrepancies in the size of the upper and lower jaws—such as an oversized lower jaw (macrognathia) or an undersized upper jaw (micrognathia)—inevitably lead to a bite misalignment.
Environmental or habitual factors influence alignment during the developmental years, particularly in early childhood. Prolonged habits like thumb sucking or pacifier use past the age of three or four can exert constant pressure on the teeth and jaw structure. An abnormal tongue posture, such as tongue thrusting, or chronic mouth breathing can also alter the balance of forces that determine where the teeth settle.
Dental factors are local issues within the dental arch that disrupt alignment. The premature loss of a primary tooth can cause adjacent teeth to drift, leading to a lack of room for the permanent tooth to erupt. Conversely, prolonged retention of a primary tooth can block a permanent tooth’s path. Other factors include extra teeth (supernumerary teeth), impacted teeth, or teeth that are abnormally large or small.
Comprehensive Treatment Options
The correction of malocclusion is primarily handled by an orthodontist, who develops a treatment plan based on the type and severity of the condition. Treatment often begins with orthodontic appliances, which apply controlled forces to reposition teeth and modify jaw growth.
Traditional metal or ceramic braces use brackets bonded to the teeth and connected by archwires to guide teeth into position. These fixed appliances are highly effective for managing complex movements and correcting almost any type of malocclusion. Alternatively, clear aligners offer a removable option, using a series of custom-made trays to achieve gradual tooth movement.
For growing children, removable appliances are utilized for early intervention to address skeletal issues. A palatal expander is a device used to widen a narrow upper jaw, resolving posterior crossbite and creating space for crowded teeth. In cases of severe jaw discrepancy, headgear may be employed to influence the direction of jaw growth.
In the most severe cases of skeletal malocclusion, particularly in adults where jaw growth is complete, orthognathic surgery (jaw surgery) may be necessary. This procedure involves surgically repositioning the upper or lower jaw to achieve a correct skeletal relationship, often combined with orthodontic treatment. Following the active phase, a retainer is required to hold the teeth in their new alignment and prevent shifting.