Objective: The purpose of this study was to develop a method of accurately quantifying the wear facet, and relating the wear facet size to the forces applied by the Iowa Tooth Wear Machine. Methods: Ten un-erupted third molars were used for this study. The teeth were mounted in the Iowa Tooth Wear Machine with opposing proximal surfaces. Samples were run with a 0.250mm stroke length for 645,120 cycles under 5 pounds of weight. An optical scanner was used to digitize the initial and final interproximal wear facets. AnSur© software (Regents, University of Minnesota) was used to process and analyze the interproximal surfaces in terms of area (mm2), volume (mm³), and depth (µm). Results: All samples were subject to identical magnitude and frequency of forces. The results show that there was considerable variation in volume loss between the samples. Results show similar amounts of volume loss in samples 3, 4, 6, 7, 8, 9, and 10 with 1, 2, and 5 showing a considerably greater amount of wear. Conclusions: The results suggest that there may be other compounding factors involved with facet formation, and the force magnitude and frequency alone does not determine the volume of enamel loss.

Introduction: Treating adolescent maxillary constriction often includes a traditional RME appliance, with the aim of creating a separation of the midpalatal sutural (MPS). However, maxillary skeletal expansion becomes more difficult with age due to increased facial and mid-palatal, skeletal resistance. An emerging treatment option with the hopes of overcoming this skeletal resistance is a mini-screw assisted RME appliance. The purpose of this study is to evaluate the age and maturation at which successful separation of the maxillary MPS can be achieved, and whether or not this can be improved with the utilization of a mini-screw assisted RME appliance. Materials and Methods: In this prospective clinical trial, N=96 (n=43 M, n=53 F) consecutively treated subjects exhibiting maxillary skeletal constriction underwent traditional RME treatment and N=13 (n=7 M, n=6 F) underwent MARME treatment utilizing mini-screws. Subjects were also classified into either pre-pubertal or post-pubertal groups based on maturation. Evidence of MPS separation was confirmed by the development of a diastema between upper central incisors and using a maxillary occlusal radiograph. Results: Average age of the 96 subjects with traditional RME treatment was 13.8 years with 71.9% achieving successful separation of the maxillary MPS. Sutural separation occurred with traditional RME for 96% of the pre-pubertal group compared with 62% of the post-pubertal group. There was also a significantly strong negative correlation between age and percent ability to get MPS separation with traditional RME. In contrast, average age of mini-screw RME subjects was 17.1 years (n=13), all were classified as post-puberty, and MPS separation occurred 100% of the time. Conclusions: Utilization of mini-screw assisted RME is a good option for clinicians when treating post-pubertal adolescents and early adult patients. However, MPS separation is highly likely to occur in pre-pubertal patients treated with traditional RME. As a result, patient age and maturation should be taken into account when deciding between traditional or mini-screw assisted RME treatment.

Introduction: Individuals with short lower anterior facial height (LAFH), reduced mandibular plane angle, and excessive overbite resulting from upward and forward mandibular rotation are traditionally classified as skeletal deep bites. Our purpose was to explore phenotypic variation within short LAFH individuals using geometric morphometric methods. Methods: Cephalograms of 101 individuals (64 female, 37 male; age range: 7-62 years) with LAFH to total anterior facial height (TAFH), ratio (LAFH/TAFH), at or below 52.6% were studied. Principal component analysis, cluster analysis, and canonical variate analysis captured phenotypic variation and identified homogenous groups. Results: Four principal components were identified which accounted for 49% of the variation within the skeletal vertical and sagittal dimensions, flexure of the gonial angle, and incisor angulation. Cluster analysis resulted in 3 discrete short LAFH subpenotypes. Conclusions: Within the selected population of short LAFH individuals, we found: A range of morphologic variation. Convergent and divergent facial patterns with concomitant variation in gonial angle and ramus height. Anteriorly directed condylar morphology correlated with characteristics of extreme forward mandibular rotation; less anteriorly directed condylar morphology correlated with characteristics of backward mandibular rotation. Overbite magnitude is independent of vertical skeletal relationship and/or characteristics of forward mandibular rotation.

Purpose: To evaluate the efficacy of a fluoride-containing orthodontic primer in preventing demineralization adjacent to brackets and compare the quality of enamel on tooth surfaces that received interproximal reduction (IPR). Methods: Patients at the VCU Orthodontic clinic who consented to orthodontic treatment involving extraction of at least 2 premolars were recruited to this pilot clinical study. Brackets were bonded to premolars using one of two primers, fluoride-containing experimental or control. IPR was also performed, and the experimental primer was applied to randomly selected teeth. Extracted teeth were analyzed visually for the presence of white spot lesions (WSLs). Micro-CT analyses were also performed to evaluate demineralization and measure the lesions. Results: A total of 18 teeth from 6 subjects were included in the following analyses. Based on micro-CT imaging, lesions were found on 89% of teeth treated with the experimental primer compared to 67% with the control primer, but this difference was not statistically significant (p=0.5765). There was also no significant difference between the depths of the lesions (p=1.00), handedness (p=0.5765), hygiene (p=0.7804), or time in the mouth (p=0.5601). According to visual examination, there was no significant difference in the incidence of WSLs between the two groups (89% and 89%; p=1.00) Also, there was no association with treatment (p=1.00), handedness (p=1.00), hygiene (p=0.1373), or time in the mouth (p=0.2987). No differences were noted on the microstructural characteristics of enamel at the IPR sites. Conclusion: Fluoride-containing primers do not seem to provide any additional benefit over conventional non-fluoride primers in orthodontic patients.

Introduction: Nasal septal deviation may contribute to facial asymmetry. The purpose of this study was to assess the relationship between nasal septal deviation and facial asymmetry using three-dimensional geometric morphometric methods. Methods: Computed tomographic scans were made of n=55 adult subjects, and septal deviation was calculated as a percentage of septal volume relative to the volume of a modeled non-deviated septum. Skeletal landmarks representing nasal, palatal, and lateral facial regions were recorded, and landmark data was superimposed using Procrustes analysis. ANOVA/MANOVA tests determined degree of overall fluctuating and directional asymmetry. Finally, correlation analysis and multivariate regression were used to examine relationship between septal deviation and asymmetry of the individual facial regions. Results: Septal deviation was significantly correlation with lateral deviation of the nasal floor, vertical and lateral asymmetry of the anterior palate and width asymmetry of the posterior posterior palate and posterior alveolar thickness, but was uncorrelated with the overall magnitude of asymmetry. There was no correlation between septal deviation and lateral facial asymmetry. Conclusion: Nasal septal morphology is linked to nasal and palatal asymmetry. Deviated growth of the septum may pre-dispose patients to dental and skeletal asymmetries that have important orthodontic considerations.

Orthodontic materials are evolving. The aim was to find out how this affects treatment outcomes. Brackets are getting smaller and smaller in the name of esthetics and patient comfort. The aim of this study was to find out if intrabracket width (the horizontal distance between bracket tie wings) had any effect on maxillary anterior root torque. We also aimed to find out if three common orthodontic archwires were capable of delivering the torque necessary to achieve ideal root torque. A machine was developed to simulate lingual root torque of an upper central incisor. This is the first test of its kind, presumably because intrabracket width is thought to have no effect on torque. It was found that all three archwire groups were capable of delivering the torque needed to accomplish treatment goals. Torque was found in this experiment to be expressed differently in wide and narrow brackets. The wider bracket required less torque in the archwire to produce the same force compared to that in a narrow bracket. The implications of this finding are that orthodontists may need to adjust the torque being placed in archwires based upon the intrabracket width of the brackets they are using.

May 2008. A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

June 2008. A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

June 2010. A thesis submitted to the College of Dental Medicine of Nova Southeastern University in partial fulfillment of the requirements for the degree of Master of Science [Dental Medicine].

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Abstract ASSESSMENT OF THE ROLE THAT SECOND MOLARS PLAY IN BITE-OPENING DURING ORTHODONTIC TREATMENT IN ADOLESCENTS: A RETROSPECTIVE, CEPHALOMETRIC STUDY DEGREE DATE: DECEMBER 6, 2013 Christopher B. Trockel, D.D.S. COLLEGE OF DENTAL MEDICINE NOVA SOUTHEASTERN UNIVERSITY Thesis Directed By: Shiva Khatami D.D.S., Ph.D, Committee Chair Mark Hall, D.D.S., Committee Member Abraham Lifshitz, Committee Member Objectives: This study aimed to investigate the role that second molars play in increasing the facial vertical dimension by comparing vertical changes experienced in growing patients, who had their second molars incorporated into the orthodontic appliance, with those that did not. The study investigated associations between the vertical changes experienced through treatment and the initial vertical classification of the patients (normo-, hypo-, and hyperdivergent). Background: Many studies have investigated the changes in the vertical dimensions that occur in orthodontic treatment. It has been shown that almost all orthodontic appliances produce extrusion whether desired or not. In theory, this extrusion may lead to an increase of the skeletal vertical dimension. Conventional wisdom says that second molars play a significant role in vertical control during treatment. Therefore, some practitioners advocate viii incorporating the second molars as soon as possible in treatment to help open the bite. It is also thought that it may be wise to not incorporate the second molars during treatment at all in cases with an open bite tendency. Methods: Eighty de-identified pre-treatment cephalometric radiographs (40 with second molars bonded and 40 without second molars bonded) from growing patients treated at the orthodontic clinic at Nova Southeastern University were analyzed and compared to their post-treatment analogs. Twelve linear and angular measurements were made (overbite, maxillary molar to palatal plane, mandibular molar to mandibular plane, upper anterior dentoalveolar height, lower anterior dentoalveolar height, upper anterior facial height, lower anterior facial height, total posterior facial height, lower posterior facial height, UAFH/LAFH ratio, mandibular plane angle, and Y-axis). Results: The results indicated that the vertical dimension was not significantly altered based solely on whether or not the second molars were incorporated into the orthodontic appliance. Changes experienced by both groups (bonded and non bonded) and all three subgroups (hypo-, normo-, and hyperdivergent) were consistent with what would be expected for growth alone. Conclusion: Bonding second molars in a growing population during orthodontic treatment does not significantly affect the vertical dimension, regardless of the patient's initial skeletal vertical classification.