Advisory Committee Chair
Advisory Committee Members
Date of Award
Degree Name by School
Master of Science (MS) School of Dentistry
Short root anomaly (SRA) is a poorly understood developmental defect of root formation. Patients with this condition have short roots with rounded apexes and significantly reduced root to crown (R/C) ratios1, which can compromise dental care and may increase the risk of root resorption during tooth movement. SRA prevalence ranges from 1-10% but has not been studied in many ethnic populations. Furthermore, its genetic basis is undetermined. Our goals were to determine the prevalence of SRA among various ethnicities, identify genetic variations contributing to its phenotype, and evaluate how SRA can affect the outcome of orthodontic treatment. This study found an overall SRA prevalence of 5.25%, with a significant increase in Hispanic individuals (11.52%) compared to African American (1.03%) and Caucasian groups (3.23%). Our data did not show any significant differences in prevalence between African American and Caucasian patients, nor between males and females. Most of the SRA patients’ R/C ratios were statistically different than norms (p0.05). However, there were no significant differences between SRA patients of each ethnicity and gender, except for maxillary canines, which had reduced ratios in African American females (p0.05). iii Additionally, we completed genetic analysis in five families. We did not find one variant that was observed in all SRA patients. However, common variants within genes vital to the Wnt and TGF-/BMP root formation signaling pathways were detected. Mutations were observed in LRP6, LRP1, DKK3, APC2, Wnt8a, Lef1, BMP3, and Smurf-1. Most of these variations were caused by exonic single nucleotide variants resulting in significantly deleterious missense mutations. Pedigree analysis revealed autosomal dominant inheritance in three families, autosomal recessive or de novo mutation in another, and an undetermined pattern in the remaining family. Finally, we showed that maxillary central and lateral incisors, maxillary second molars, and mandibular lateral incisors indicated the most consistent pattern of root resorption during orthodontic treatment in the case series of SRA patients. While we did not identify any definitive predictors of root resorption related to the SRA phenotype, it is evident that this amount of resorption is clinically significant, especially considering the initial R/C ratios were already decreased in these patients.
Sharp, Lauren, "Short Root Anomaly: Prevalence, Genetics, And Its Effect in Orthodontic Treatment" (2023). All ETDs from UAB. 117.
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