hypodontia

Hypodontia is the developmental absence of one or more permanent teeth, excluding third molars. When six or more teeth are missing, it is termed oligodontia; complete absence of all teeth is anodontia. Hypodontia can be non-syndromic or associated with systemic conditions such as ectodermal dysplasia, or with chromosomal or non-syndromic syndromes. The condition is influenced by genetic factors, with mutations in genes such as MSX1, PAX9, AXIN2, and EDAR contributing in some families. Environmental factors during tooth development may also play a role.

Most frequently missing teeth are the maxillary lateral incisors, second premolars (often bilateral), and mandibular second premolars. The prevalence varies by population, but hypodontia affects a minority of individuals, with a slightly higher occurrence in females in some studies.

Diagnosis is usually established in the mixed dentition period by clinical examination and radiographs (panoramic radiographs or CBCT) to confirm tooth absence and rule out delayed eruption or impaction. Early diagnosis helps planning.

Management requires a multidisciplinary approach. Orthodontists may close spaces or preserve them to enable future restoration. Restorative options include veneers or crowns when aesthetics are a concern, and, in individuals with completed jaw growth, implants or fixed/removable prostheses to replace missing teeth. Growth considerations are important for treatment timing in children.

Prognosis depends on the number and position of missing teeth, as well as access to multidisciplinary care. With coordinated orthodontic, surgical, and prosthetic treatment, functional occlusion and aesthetics can be significantly improved.