Thesis (M.S.)--University of Michigan, 1962.

Thesis (M.S.)--University of Michigan, 1962.

Thesis (doctoral)--Katholieke Universiteit te Nijmegen. / Translation of: Het proces van tanderuptie in beagle honden.

Universiẗat, Diss., 2004--Würzburg.

Orientadores: Silvana Pereira Barros, Jose Merzel / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-05T13:43:16Z (GMT). No. of bitstreams: 1 Silva_MarcoAntonioDiasda_D.pdf: 2250245 bytes, checksum: 22329a07ea6108d7bacfd889fc338a72 (MD5) Previous issue date: 2005 / Resumo: O propósito deste estudo foi avaliar a influência do tratamento com doses intermitentes PTH na morfologia e na quantidade das fibras de Sharpey de dentes de crescimento contínuo em diferentes condições funcionais e na ultraestrutura dos hepatócitos de ratos. Os animais foram preparados de forma a apresentar normo, hipo e hiperfunção. O grupo tratado recebeu 40¿um¿g/kg PTH três vezes por semana, durante trinta dias e o grupo controle recebeu a mesma dose de veículo (ac. acético 1%). A) Utilizando microscopia eletrônica de varredura, foi avaliada a densidade de fibras de Sharpey na face lingual do alvéolo de incisivos. Os resultados demonstraram que os animais tratados com PTH, nas três condições funcionais apresentam uma maior densidade das fibras de Sharpey em relação aos respectivos controles.A mesma diferença se observa quando se considera apenas as fibras de Sharpey mineralizadas. B) No fígado cortes semifinos e ultrafinos foram analisados, através de microscopia de luz e eletrônica de transmissão e obtida a densidade volumétrica de hepatócitos e organelas. Foi demonstrado que os hepatócitos dos animais tratados com PTH apresentam aumento do retículo liso e diminuição da reserva deglicogênio. Os resultados indicam que doses intermitentes de PTH administradas por um período de 30 dias promovem um aumento da densidade de área das fibras de Sharpey em particular das totalmente mineralizadas, o que pode ter resultado no aumento da resistência do ligamento periodontal o que explicaria o retardo da velocidade eruptiva observado em animais tratados. As alterações ultraestruturais descritas nos hepatócitos indicam um aumento no metabolismo hepático promovido pelo hormônio / Abstract: The aim of this study was to evaluate the effects of PTH intermittent treatment on periodontal Sharpey fibers and hepatocytes ultrastructural components of wistar rats. The animals were divided in groups and exposed to different occlusaI forces, normal occlusion, hyperfunction and hypofunction. PTH treated animais received 40 'mu¿g/Kg of PTH, three times a week, during thirty days and the rats from control group received vehicle in following the same protocol. Sharpey fibers density was evaIuated through scanning electron microscopy in the lingual face of lower incisors. We observed that PlH treated animaIs presented increased density of Sharpey fibers and more mineralized fibers, in the three occ1usal conditions analyzed, when compared to the control. Transmission electronic microscopy morphometric anaIysis demonstrated that hepatocytes from PTH treated animals presented an increase of smooth endoplasmatic reticulum and a decrease on glycogen volumetric density. These results indicate that thirty days of PTH intermittent administration are responsible by an increase in aIveolar Sharpey fibers density and this evidence might be associated to an enhancement of periodontal ligament resistance and consequently to reduced eruptive rates previously observed. In hepatic tissue the increase in smooth endoplasmatic reticulum and the reduction in glycogen amount induced by PTH might be related to an enhancement of hepatic metabolism promoted by the hormone / Doutorado / Histologia / Doutor em Biologia Buco-Dental

Urticarial vasculitis is a relatively rare diagnosis in a patient presenting with urticaria. The process is classically described as a generalized eruption, painful more so than pruritic, lasting longer than 24 hours. Two forms of urticarial vasculitis have been described: ahypocomplementemic form more commonly associated with systemic disease, and a normocomplementemic form that is generally limited to the skin. We report on a uniquely distributed vasculitic eruption restricted mainly to the anterior belt line area in a patient presenting with urticaria and intense pruritus. Urticarial vasculitis as a unique entity is reviewed along with its clinical and histopathologic presentation and the pharmacologic agents used for treatment.

Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this study was to investigate the possibility of accomplishing simultaneous intrusion and distal root movement of monkey premolar teeth utilizing the molar teeth as anchorage. Four Macaque speciosa monkeys were used as the experimental specimens. Root springs of the type used in the segmented arch technique were used to apply unequal moments to the premolar and molar teeth. The root movement was accomplished by a couple generated by the unequal moments. The results were analyzed cephalometrically and histologically. It was found that it is possible to accomplish distal root movement and intrusion of the monkey premolars when the anchorage is restrained from eruption. When the anchorage is not restrained intrusion is minimal. Root resorption was found to be associated with the magnitude of the difference in the moments applied and the amount of tooth movement.

Indiana University-Purdue University Indianapolis (IUPUI) / It has been proposed that jaw deformation during function may be a contributor to supraosseous tooth eruption. This could be through a transient pressure gradient in the flexed bone and/or tension in the PDL fibers produced by socket deformation. Thus, the purpose of this study was to determine if forces applied to a fresh frozen canine mandible can lead to occlusal displacement of a tooth. Seven hemisected canine mandibles (14 specimens) were used to test this hypothesis. A force cycle (10 N to 100 N to 300 N) was applied by a Bionix testing machine (MTS TM Systems Corp., Minneapolis, Minn.) to the mandible in three point bending. Digital radiographs were taken at each change in force level using computer digitized radiography (CDR, TM Schick Technologies, Inc., Long Island City, N.Y.). By measuring the relative movement of metal markers (1 mm steel balls) placed into the mandible and the crown of the 2nd premolar, the amount of tooth eruption was calculated. With cyanoacrylate cement (Archer® Instant Bonding Adhesive, Tandy Corp, Ft. Worth, Texas) injected into the PDL space of the same tooth, the test was repeated one week later. These "ankylosed" teeth served as controls. The eruption distances were compared between the experimental and the ankylosed teeth by means of repeated measures analysis of variance. The only significant occlusal displacement was noted as the force was initially raised to 100 N (21.7 ± 40.6 μm). Due to the possible breakdown of the cyanoacrylate cement, the ankylosed teeth also showed evidence of eruption with the continued application of force. Although significant eruption was noted, the displacements were very small. PDL degradation, viscoelastic behavior, measurement of small displacements, limited resolution radiography, and two dimensional analysis are contributing factors to the uncertainty of the results. Further investigation is required to determine if jaw deformation during function is a viable mechanism leading to the occlusal displacement of teeth.

The purpose of this cross-sectional study was to determine whether patients exhibiting third molar agenesis also exhibit delayed development and/or eruption of the adjacent second molar. The initial panoramic radiographs of 739 patients, 13-17 years of age, from the University of Iowa's Department of Orthodontics were examined. The developmental stage of each second molar according to Demirjian's 8-stage classification system, the eruption stage of each second molar, along with the presence or absence of each third molar were recorded, and Pearson chi-squared tests were used to determine differences in developmental and eruptive timing between those missing third molars and those with third molars present. We conclude that patients missing their maxillary third molars exhibit delayed development of the adjacent maxillary second molars. In addition, patients missing any of their four third molars exhibit delayed eruption of their adjacent second molars. The findings also suggest that mandibular second molars develop later than, but erupt earlier than, maxillary second molars.

abstract: Assessments for the threats posed by volcanic eruptions rely in large part on the accurate prediction of volcanic plume motion over time. That predictive capacity is currently hindered by a limited understanding of volcanic plume dynamics. While eruption rate is considered a dominant control on volcanic plume dynamics, the effects of variable eruption rates on plume rise and evolution are not well understood. To address this aspect of plume dynamics, I conducted an experimental investigation wherein I quantified the relationship between laboratory jet development and highly-variable discharge rates under conditions analogous to those which may prevail in unsteady, short-lived explosive eruptions. I created turbulent jets in the laboratory by releasing pressurized water into a tank of still water. I then measured the resultant jet growth over time using simple video images and particle image velocimetry (PIV). I investigated jet behavior over a range of jet Reynolds numbers which overlaps with estimates of Reynolds numbers for short-duration volcanic plumes. By analysis of the jet boundary and velocity field evolution, I discovered a direct relationship between changes in vent conditions and jet evolution. Jet behavior evolved through a sequence of three stages - jet-like, transitional, and puff-like - that correlate with three main injection phases - acceleration, deceleration and off. While the source was off, jets were characterized by relatively constant internal velocity distributions and flow propagation followed that of a classical puff. However, while the source was on, the flow properties - both in the flows themselves and in the induced ambient flow - changed abruptly with changes at the source. On the basis of my findings for unsteady laboratory jets, I conclude that variable eruption rates with characteristic time scales close to eruption duration have first-order control over volcanic plume evolution. Prior to my study, the significance of this variation was largely uncharacterized as the volcanology community predominately uses steady eruption models for interpretation and prediction of activity. My results suggest that unsteady models are necessary to accurately interpret behavior and assess threats from unsteady, short-lived eruptions. / Dissertation/Thesis / Ph.D. Geological Sciences 2012