Orthodontics is the specialized field of dentistry focused on diagnosing, preventing, and treating dental and facial irregularities. The goal of orthodontic care is to correct a malocclusion, or “bad bite,” which involves the misalignment of teeth and jaws that affects function, health, and appearance. While many people believe the need for braces is purely cosmetic, the decision to seek treatment is primarily driven by underlying functional and health problems. Determining the percentage of people who truly require intervention requires differentiating between common misalignment and the severity warranting clinical correction.
Global and National Prevalence of Orthodontic Need
Malocclusion, defined as any deviation from an ideal bite, is common globally. Studies estimate the overall prevalence of some degree of malocclusion ranges between 60% and 75% of people worldwide. In children and adolescents, this prevalence can be higher, with some reports indicating up to 93% may have some form of misalignment.
However, the percentage of individuals with malocclusion severe enough to warrant professional intervention is significantly lower. Using standardized clinical metrics, the global pooled prevalence of a definite need for orthodontic treatment is estimated to be around 46%. For functional problems alone, the percentage is approximately 45%. In Western countries, such as the United States, research suggests that 57% to 59% of the population exhibits varying levels of need. In the United Kingdom, approximately one-third of all children require orthodontic treatment for health reasons.
Clinical Criteria for Determining Orthodontic Need
Orthodontists quantify the need for treatment by evaluating the relationship between the upper and lower teeth and jaws, moving beyond visual assessment. The most widely recognized system for classifying a malocclusion is Angle’s Classification, which categorizes the bite based on the position of the first permanent molars.
A Class I malocclusion indicates a proper molar relationship but includes issues like crowding or spacing of the front teeth. A Class II malocclusion describes a situation where the upper jaw or teeth are positioned too far forward relative to the lower jaw, often leading to a noticeable overjet. Conversely, a Class III malocclusion occurs when the lower jaw or teeth protrude too far forward, resulting in an underbite. These classifications define the type of bite problem but not necessarily the severity or necessity of treatment.
To assess the clinical urgency for treatment, many public healthcare systems use standardized tools like the Index of Orthodontic Treatment Need (IOTN). The IOTN uses a scale with two components: the Dental Health Component (DHC) and the Aesthetic Component (AC). The DHC measures specific features of the malocclusion, such as the extent of overjet, degree of crowding, or presence of an open bite, to determine if the condition affects dental health or function. Malocclusions scoring high on the DHC are considered to have a definite, health-based requirement for treatment.
Key Factors Influencing Malocclusion
The development of a malocclusion is influenced by both inherited traits and environmental factors acting on the growing face and jaw structures. Skeletal discrepancies are largely genetic, arising from a mismatch in the size or shape of the upper jaw (maxilla) and the lower jaw (mandible). For instance, a Class III malocclusion (underbite) often shows a strong familial tendency due to excessive growth of the mandible, with specific genes implicated in this size discrepancy.
Environmental and habitual factors, particularly during childhood, also play a significant role in shaping the alignment of the dental arches. Prolonged thumb or finger sucking beyond the age of five creates sustained pressure against the teeth and supporting bone. This force can lead to specific problems, including an anterior open bite (where the front teeth do not meet), an exaggerated overjet, and a posterior crossbite.
Chronic mouth breathing, often caused by issues like allergies or enlarged tonsils, is another habit that disrupts normal growth. Nasal breathing encourages the tongue to rest against the palate, providing a gentle, outward force that supports the proper width development of the upper jaw. When a child habitually breathes through the mouth, the tongue rests low, leading to a muscle imbalance. This imbalance can result in a narrowed upper jaw and a downward and backward rotation of the lower jaw, frequently contributing to a Class II malocclusion.
Treatment Rates Across Age Groups
The percentage of the population who ultimately receive orthodontic correction is considerably lower than the percentage who could benefit from treatment. In the United States, a large majority of those who utilize orthodontic services are young people, with approximately 67.6% of patients being under the age of 18. Treatment rates peak around the age of 13 and 14, which aligns with the ideal timing for intervention while the jaw is still growing.
Adult treatment is a rapidly expanding segment of orthodontic care, driven by technological advancements and changing social perceptions. Recent surveys indicate that orthodontists have seen an increase in adult patients seeking treatment, primarily in the 26 to 55 age bracket. While functional improvement remains a goal, the primary motivator for many adults is aesthetic, with nearly 70.4% of patients citing appearance as their main reason for seeking treatment.
The gap between the clinical need for braces and the actual treatment rate is often influenced by non-clinical factors. Access to care, insurance coverage, and the substantial cost of private treatment are major barriers. Therefore, while roughly half the population has a malocclusion that could benefit from correction, the decision to proceed balances clinical necessity with financial and aesthetic considerations.