Developmental abnormality and malposition characteristics of teeth adjacent to the alveolar cleft in patients with cleft lip and palate and treatment progress

Cleft lip and palate (CLP) are common congenital craniofacial developmental disorders with a high incidence rate among newborns. Due to the influence of the cleft, an increased frequency of anomalies occurs in cleft-adjacent teeth. This review summarizes the abnormality of tooth development and malposition characteristics of the central incisors, lateral incisors, and canines adjacent to the alveolar cleft in CLP patients and treatment progress in order to provide information for related clinical treatment and research. The literature reveals that central incisors, lateral incisors, and canines adjacent to the alveolar cleft exhibit various types and degrees of abnormalities. The alveolar cleft-adjacent central incisors show significantly smaller mesiodistal diameters, root lengths, and root volumes compared to the non-alveolar cleft side, while the crown-to-root ratio is larger. Further, they are inclined distally and lingually compared to the non-alveolar cleft side. The alveolar cleft-adjacent lateral incisor is the most common missing or impacted tooth and is often affected by microdontia. The total length and root length of the alveolar cleft-adjacent canines are significantly smaller, while the crown-to-root ratio is larger on the alveolar cleft side. In addition, they are inclined mesially and buccally compared to the non-alveolar cleft side. Further, they are higher positioned and located closer to the midline. For developmental anomalies, impacted central incisors can be addressed by orthodontic space preparation to facilitate eruption or surgical crown exposure and orthodontic traction. Treatment of missing lateral incisors can involve orthodontic closure of the gap or preservation of the space for subsequent prosthetic restoration. When lateral incisors present with developmental defects, such as microdontia, peg-shaped teeth, or invaginated teeth, a comprehensive decision is necessary to determine whether to retain and restore or extract the malformed lateral incisors. Treatment of impacted canines after bone grafting involves either extraction or traction to facilitate the eruption of the impacted tooth. For malposition, presurgical orthodontic treatment can correct teeth with excessive inclination or rotation on the cleft side to improve the effectiveness of bone grafting surgery. Postsurgical orthodontic treatment can enhance the stability of bone grafting surgery. Although numerous studies have explored the dental characteristics of patients with CLP, the lack of applicability and specificity still need to be elucidated, thus indicating the need for further research.