Permanent tooth agenesis in non-syndromic Robin sequence and cleft palate: prevalence and patterns.

OBJECTIVES: Partial tooth agenesis is frequently observed in Robin sequence. Tooth anomalies are increasingly considered as an extended phenotype of the cleft palate population. The study objective was to compare the prevalence and patterns of tooth agenesis in a group of patients with non-syndromic Robin sequence (ns-RS) and a group with non-syndromic cleft palate (ns-CP). MATERIALS AND METHODS: The panoramic radiographs of 115 ns-RS and 191 ns-CP patients were assessed for agenesis of the permanent dentition (excluding third molars) and the patterns recorded using the Tooth Agenesis Code. RESULTS: Partial tooth agenesis was observed in 47.8% of ns-RS and 29.8% of ns-CP patients with a greater prevalence in the mandibula than in the maxilla, particularly in ns-RS. The teeth most frequently absent in both groups were the mandibular second premolars and maxillary lateral incisors. Tooth agenesis was bilateral in two-thirds of affected ns-RS patients and one-half of ns-CP patients. In ns-RS, bilateral agenesis of the mandibular second premolars was more frequently observed in female than that in male patients. Completely symmetrical patterns of hypodontia were found in around 45% of ns-RS patients with tooth agenesis compared to 35% in ns-CP. No association was found between the extent of the palatal cleft and the severity of hypodontia. CONCLUSION: Tooth agenesis is more prevalent in ns-RS than that in ns-CP, demonstrates a much greater predilection for the mandible in ns-RS, and bears no relation to the extent of the palatal cleft. CLINICAL RELEVANCE: When compared to ns-CP, additional developmental disturbances are likely involved in the etiology of tooth agenesis in ns-RS. Future research could help identify the underlying genetic traits and aid in classifying patients in those with and without expected tooth agenesis in order to facilitate orthodontic management strategies.

Patterns of tooth agenesis in patients with orofacial clefts.

Orofacial clefts are a common oral disorder associated with tooth agenesis. As information on the simultaneous absence of teeth can be an aid in treatment planning, a large sample of orofacial cleft patients was examined. The sample consisted of 910 patients with cleft lip and palate. Tooth agenesis was assessed on the basis of at least two panoramic radiographs and patient records. Third-molar agenesis was determined in 474 patients. Patterns of tooth agenesis were analysed using Tooth Agenesis Code (TAC) values, according to VAN WIJK & TAN. Per quadrant, at least 90% of patients could be described according to three different patterns. In the maxilla, 85% of patients with tooth agenesis had a TAC-value of 2, 16, or 18 on either the left side, right side or bilaterally. In the mandible, 90% of patients with tooth agenesis had a TAC-value of 16, 1 or 2 on either the left side, right side or bilaterally. In patients with tooth agenesis, patterns were symmetrical in the maxilla in 18.8% and in the mandible in 51%. More extended cleft types were associated with a higher prevalence of tooth agenesis. Third-molar agenesis (prevalence = 22.4%) was significantly related to the prevalence of other absent teeth. These results show which patterns of tooth agenesis can be expected to occur in most orofacial cleft patients.

Tooth Agenesis Patterns in Orofacial Clefting Using Tooth Agenesis Code: A Meta-Analysis.

Individuals with orofacial clefting (OFC) have a higher prevalence of tooth agenesis (TA) overall. Neither the precise etiology of TA, nor whether TA occurs in patterns that differ by gender or cleft type is yet known. This meta-analysis aims to identify the spectrum of tooth agenesis patterns in subjects with non-syndromic OFC and controls using the Tooth Agenesis Code (TAC) program. An indexed search of databases (PubMed, EMBASE, and CINAHL) along with cross-referencing and hand searches were completed from May to June 2019 and re-run in February 2022. Additionally, unpublished TAC data from 914 individuals with OFC and 932 controls were included. TAC pattern frequencies per study were analyzed using a random effects meta-analysis model. A thorough review of 45 records retrieved resulted in 4 articles meeting eligibility criteria, comprising 2182 subjects with OFC and 3171 controls. No TA (0.0.0.0) was seen in 51% of OFC cases and 97% of controls. TAC patterns 0.2.0.0, 2.0.0.0, and 2.2.0.0 indicating uni- or bi-lateral missing upper laterals, and 16.0.0.0 indicating missing upper right second premolar, were more common in subjects with OFC. Subjects with OFC have unique TA patterns and defining these patterns will help increase our understanding of the complex etiology underlying TA.