Thesis (M.S.)--University of Michigan, 1961.

Thèse (M.A.)--Université Laval, 1995. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thèse (M.A.)--Université Laval, 1995. / Includes bibliographical references.

Disseration (Ph. D.)--Eberhard-Karls-Universität, 1935.

Thesis (doctoral)--Tübingen, 1933. / Includes bibliographical references (p. 41-42).

<p>The aim of this project was to measure changes in dimension of the first three primary rugae and to evaluate tooth movement in the maxilla during orthodontic treatment in patients treated with and without premolar extractions.</p>

<p>The aim of this project was to measure changes in dimension of the first three primary rugae and to evaluate tooth movement in the maxilla during orthodontic treatment in patients treated with and without premolar extractions.</p>

The purpose of this study was to compare, in vitro, the effectiveness of the resin sealants ProSeal™, OrthoCoat™, SeLECT Defense™, and Biscover LV™ on the inhibition of enamel demineralization after being subjected to extensive mechanical toothbrush abrasion. Seventy-five extracted third molars were divided into five groups - control, ProSeal, SeLECT Defense, OrthoCoat, and Biscover LV. All of the teeth, with the exception of the control group, weretreated with one of the four sealant materials per the manufacturer's instructions. Teeth were mounted in an acrylic ring and stabilized with a vinyl polysiloxane impression material. The mounted teeth were placed in the Prototech Toothbrush Wear Simulator and a soft-bristled toothbrush was placed over the buccal surface of the tooth. Each tooth was subjected to 15,000 horizontal strokes at a rate of 120 strokes/minute and each toothbrush received a constant force of 280 g to stimulate normal manual brushing, simulating about 2 years of manual toothbrushing. Teeth from all groups were painted with a thin layer of acid-resistant varnish (nail polish), leaving a 1 mm window of exposed enamel on the buccal surface. They were then placed into a constantly circulating, room-temperature standard tenCate Demineralizing Solution (pH=4.4) consisting of 2.20mM Ca2+, 2.20 mMPO4 3-, 0.05mM Acetic acid and 0.025ppm F- for 96 hours. Three sections were made of each tooth and the sections were examined under a polarized light microscope. Descriptive statistics were conducted with the study data. The one-way ANOVA with post-hoc Ryan-Einot-Gabriel-Welsch multiple range test was used to determine whether there was a significant difference in lesion depth between sealant materials. The following conclusions were made: All materials tested provided a significant reduction in enamel demineralization as compared to untreated controls. SeLECT Defense and OrthoCoat both resulted in a 64% decrease in lesion depth. Biscover LV provided a 67% decrease in lesion depth. Pro Seal provided significantly more protection (82% reduction) than the other three sealant materials: SeLECT Defense, OrthoCoat, and Biscover LV. Pro Seal, SeLECT Defense, OrthoCoat, and Biscover LV, should all be considered effective preventive treatments that do not require patient compliance for success. Pending further clinical investigation, Pro Seal should still be considered the gold standard for preventing enamel demineralization in orthodontic patients.

Objective: The primary objective of this study was to examine the effect that maximum insertion torque has on force resistance and stability of titanium screws in cadaver maxillae and mandibles. Materials and Methods: Forty-eight cadaver maxillary and mandibular jaw quadrants were obtained Two titanium mini-screws were placed in each jaw quadrant and maximum insertion torque was measured. Each mini-screw was subjected to tangential force application oriented perpendicular to placement of the mini-screw and parallel to the occlusal plane. The force applied at each deflection was measured up to 1.5mm, but only the first 0.60mm of movement was investigated. This amount of displacement was selected to represent the amount of movement that would result in a clinically mobile mini-screw and potential failure. Results: The post-hoc Tukey-Kramer's test showed that mean anchorage resistance for screws placed with maximum insertion torque of less than 5Ncm was significantly lower than those observed for 5-10Ncm and greater than 10Ncm. No significant difference was found between 5-10Ncm and greater than 10Ncm. Conclusions: In vitro, mean anchorage resistance for screws placed with maximum insertion torque of less than 5Ncm was significantly lower than those placed with maximum insertion torque between 5Ncm and 10Ncm at deflections ranging from 0.12mm to 0.60mm. In terms of maximizing anchorage resistance, we recommend placement of orthodontic mini-screws with maximum insertion torque of greater than 5Ncm.

Introduction: Patients with oral clefts can present with variable occlusal anomalies often thought to be a result of surgical intervention, which makes it difficult to characterize the occlusal phenotypic spectrum of orofacial clefting. Little research has been performed on the prevalence of occlusal anomalies and whether the prevalence of these anomalies is elevated in unaffected relatives of individuals with overt oral clefts. To date, this study is the largest international collection of children with non-syndromic clefts, their relatives and controls that aim to characterize the spectrum of cleft-related occlusal anomalies compared to the general population. Methods: A total of 1017 subjects were rated: 108 subjects with clefts, 314 unaffected relatives, and 595 controls. Occlusal anomalies were identified from intraoral photographs and case-control differences were tested using logistic regression. Results: When comparing cases vs. controls, cases were more likely to have negative overjet, a posterior crossbite, and an anterior crossbite. Controls were 14 times more likely to have positive overjet than cases (P=0.0003). Cases were 13 times more likely to have a posterior crossbite than controls (P=0.0005). Cases were 17.2 times more likely than controls to have an anterior crossbite (P=0.0006). No significant differences in occlusal discrepancies were found when comparing non-affected siblings of affected probands to matched siblings of controls. Unaffected parents of cases were more likely to have spacing in both the upper arch (1.8 times, P=0.0456) and the lower arch (1.8 times, P=0.0422) when compared to control parents. Conclusions: These findings suggest that except for arch spacing, first-degree relatives of children with clefts do not have a higher genetic risk for occlusal anomalies than the general population. Our finding on increased arch spacing in the unaffected parents could point at the presence of smaller teeth overall, which has been shown before for children with clefts. In general the higher prevalence of occlusion anomalies in cases is primarily a physical consequence of the cleft and surgical interventions.