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.

"February 1999" Bibliography: leaves 119-138. The results of the study concluded that the identification of the patient's personality profile was unable to predict those patients who would not have a successful perception of the outcome of surgery, mirroring the findings of Pogrel and Scott (1994) who found that it was impossible to identify the 'psychologically bad-risk' orthognathic patient.

"February 2005" / Coursework / Bibliography: leaves 212-222. / 222 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / "Distraction osteogenesis is a surgical technique employed for bone lengthening and reconstruction of skeletal deformities. It is a biological process of new bone formation between bone segments gradually separated by incremental traction". "The purpose of this research was to conduct a pilot study to determine whether immersion fixation is adequate for evaluation of BMP-2, VEGF, Type X collagen expression in a sheep model using immunohistochemical techniques, and to evaluate the expression of these factors during the different stages of distraction osteogenesis." --leaf 14. / Thesis (D.Clin.Dent.)--University of Adelaide, Dental School (Orthodontics), 2005

Thesis (M.D.S.)--University of Hong Kong, 1993. / Includes bibliographical references. Also available in print.

Thesis (M.D.S.)--University of Hong Kong, 1994. / Includes bibliographical references. Also available in print.

Since the introduction of temporary skeletal anchorage in orthodontics during the eighties, osteosynthesis miniplates, modified with orthodontic attachments, have been increasingly used. However, no quantitative data about bone reactions around loaded miniplates, and only few prospective clinical studies with small numbers of patients, were found in the literature. Therefore, this project was set up to scientifically emphasize the use of miniplates for orthodontic anchorage with combined experimental and clinical approaches. The specific objectives of the experimental chapters of this thesis were to evaluate if orthodontic loading has an impact on bone reactions around screws supporting miniplates, and to describe the histological components of the bone-screw interface. The clinical chapters aimed to determine patients’, orthodontists’ and surgeons’ perceptions about miniplates, to assess their success rate and to describe the surgical techniques of placement and removal. The experimental study involved eighty miniplates, placed in the jaws of 10 dogs : 2 miniplates per jaw quadrant. After 2 weeks, coil springs applying a 125 g force were placed between the miniplates of an upper quadrant and the controlateral lower quadrant of each dog. The other miniplates were not loaded and were considered controls. Five dogs were sacrificed 7 weeks after implantation and 5 dogs after 29 weeks. Fluorochromes were injected at implantation and at sacrifice. Jaw quadrants were scanned with peripheral Quantitative Computed Tomography. Undecalcified sections were carried out and submitted to microradiographic analysis to assess bone-implant contact and bone volume/total volume. The sections were finally observed under UV light, stained and examined under ordinary light. The success rate in this animal study was 53 % and the proportion of stable miniplates was significantly higher in the maxilla than in the mandible. No significant difference in success rate was found between loaded and nonloaded miniplates. Mobility occurred on average 5 weeks after placement. Bone mineral density was higher around mandibular than around maxillary miniplates, but was not significantly different around loaded and nonloaded miniplates. Bone implant contact and bone volume/total volume did not differ significantly neither between the loaded and the nonloaded screws, nor according to the direction of load, whereas they increased with time. Fifty-six percent of the screws were osseointegrated. Healing reactions showed mainly limited remodelling of lamellar bone. The remaining screws were fibro-integrated. Stability and osseointegration of titanium orthodontic miniplates were thus influenced by the recipient site anatomy, but not by loading. The clinical study focused on ninety-seven consecutive patients treated with miniplates, who completed questionnaires. A total of 200 miniplates were placed by nine oral surgeons, who filled out questionnaires after placement and removal surgeries. The 30 orthodontists treating these patients also completed questionnaires concerning miniplate success, handling complexity, and effectiveness. The success rate obtained in this clinical survey was 92.5 %. Placement surgery, generally performed under local anesthesia, lasted on average 15-30 minutes per plate, and was considered by the surgeons to be very to moderately easy. Patients tolerated the miniplates well : 72 % of patients said they did not mind having the implant and 82 % reported that the surgical experience was better than expected, with little or no pain. The chief complaints were post-surgical swelling, lasting 5 days on average, and cheek irritation. The orthodontists rated these devices as easy to use and simplifying treatment. The removal surgery was shorter and considered easier than the placement surgery. Miniplates were thus well accepted by patients and providers, and were considered a useful tool especially for difficult treatments.