Thesis
Evaluating occlusal phenotypes in non-syndromic orofacial clefting
University of Iowa
Master of Science (MS), University of Iowa
Spring 2022
DOI: 10.25820/etd.006484
Abstract
ABSTRACT Introduction: Individuals with orofacial clefts may present with various occlusal anomalies such as maxillary transverse and anteroposterior hypoplasia, often thought to result from either a lack of embryonic tissue resulting in the cleft itself or the scar tissue from early surgical repair of the lip and palate. To determine whether these occlusal anomalies are due to iatrogenic, environmental, or genetic factors, one can compare the prevalence of these anomalies among cleft-affected individuals, their unaffected relatives, with whom they may share genetic cleft risk, and the general population. The purpose of this study was to evaluate occlusal anomalies among individuals with non-syndromic clefts, their relatives, and controls using the most extensive international photographic record collection to date. Methods: 3,959 subjects were rated: 400 cleft case probands, 2,293 unaffected relatives, and 1,266 controls. Occlusal anomalies were identified from sets of intraoral photographs, and comparisons between case probands or unaffected relatives to controls were tested using Chi-square (χ2) test with the Yates continuity correction or Fisher's exact test when appropriate and with a logistic regression model adjusted by ancestry and gender. Results: The occlusal characteristics of the control sample reflected what the literature typically has reported for the different ethnic backgrounds. Compared to controls, cases with clefts had significantly more discrepancies in overjet, overbite, Angle classification bilaterally, anterior open bite, posterior open bite bilaterally, all-around open bite, anterior and posterior crossbite, upper arch crowding and spacing, and lower arch spacing compared to controls, all indicating a greater need for orthodontic intervention. Unaffected relatives had significant differences in overjet, overbite, Angle classification on the left side, right posterior open bite, posterior crossbite, upper arch crowding, and lower arch spacing compared to controls, indicating a greater need for orthodontic intervention as well. Conclusions: Occlusal differences between case probands and controls were similarly found in unaffected relatives compared to controls. This finding may suggest a genetic component to the occlusal anomalies found in affected individuals with clefts and inherent phenotypic differences in cleft families compared to the general population.
Details
- Title: Subtitle
- Evaluating occlusal phenotypes in non-syndromic orofacial clefting
- Creators
- Regine Victoria Torres
- Contributors
- Lina M Moreno Uribe (Advisor)Brian J Howe (Committee Member)Mary L Marazita (Committee Member)Steven D Marshall (Committee Member)Kyungsup Shin (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Orthodontics
- Date degree season
- Spring 2022
- DOI
- 10.25820/etd.006484
- Publisher
- University of Iowa
- Number of pages
- xii, 86 pages
- Copyright
- Copyright 2022 Regine Victoria Torres
- Language
- English
- Description bibliographic
- Includes bibliographical references (pages 81-86).
- Public Abstract (ETD)
Orofacial clefts are the most common birth defects, with a prevalence of about 1 in 700 live births. Children born with cleft lip and/or palate may experience problems with feeding, speaking, and hearing, leading to adverse psychosocial sequelae. The management of clefts is interdisciplinary and usually involves surgery, dental treatment, speech therapy, and psychology. Those affected by orofacial clefts often present with dental and occlusal anomalies such as missing, misshapen, or impacted teeth, Angle Class III malocclusion, open bites, and crossbites. Research has shown that the causes of non-syndromic orofacial clefting are complex and multifactorial, believed to be the result of an interaction between environment and genetics during critical stages of development. The etiology of non-syndromic orofacial clefting remains poorly characterized despite the discovery of many candidate genes. Occlusal anomalies may be caused by genetics, the cleft itself, or sequelae of surgical cleft repair. If genetics play a primary role in the presence of occlusal anomalies, the unaffected relatives of individuals with clefts, with whom they may share genetic risk should present with a higher prevalence of occlusal anomalies compared to the general public. If the presence of the cleft or repair surgeries were the primary cause of occlusal anomalies, one would not expect a higher prevalence of occlusal anomalies among unaffected relatives compared to the general public. This study aimed to examine the presence of occlusal anomalies among populations in Nigeria, the Philippines, Colombia, the United States, and Puerto Rico. Children with clefts, unaffected relatives, and controls were evaluated using photographs. Thirty-four occlusal criteria were rated and analyzed for each patient.
The results of this study indicate significant differences in the occlusal characteristics of individuals with clefts, all pointing to a greater need for orthodontic intervention. The cleft phenotypic spectrum is characterized by occlusal anomalies consistent with maxillary deficiency in all three dimensions. Compared to the general population, individuals with clefts present with edge to edge or negative overjet; anterior and posterior open bites; and anterior, posterior, and all-around open bites. Our cleft sample also showed a lesser prevalence of Class I malocclusion in general. Instead, a greater risk for Class II or Class III was observed resulting in increased orthodontic treatment need compared to controls.
The unaffected relatives of individuals with clefts presented similarly with the characteristics of edge-to-edge or negative overjet, anterior open bites, Class II or III relationship on the left side, right posterior open bites, posterior crossbites, upper arch crowding, and lower arch spacing. These findings were similar to those of individuals with clefts, suggesting heritable traits within the cleft phenotypic spectrum.
- Academic Unit
- Orthodontics; Craniofacial Anomalies Research Center
- Record Identifier
- 9984270956202771
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