The existence of accessory canals in the furcation region of primary molars has been the subject of extensive research. The objective of this study was to use a micro-computed tomography scanner to analyze accessory canals in the furcation region of extracted primary molars. Sixty-five primary molars which were extracted for purposes not including this study were collected and scanned at a resolution of 9.0 μm using a Skyscan 1176 Micro-CT scanner. For each extracted molar collected, the patients age at the time of extraction was recorded, as well as whether the tooth came from the maxillary or mandibular arch and if the tooth was a first or second molar. DataViewer v1.5.1 software was used to analyze each scanned primary molar for the presence or absence of canals, canal patency and number of canals present. Collected data was analyzed using SPSS 20.0 for Windows. Fisher’s exact and Kruskal-Wallis tests were used to identify association between variables. Canals were observed in the furcation area of 83% of molars scanned, and patent canals were found in the furcation area of 8% of the molars. The mean number of canals per tooth was found to be 2.6. The majority of these canals were found adjacent to the periodontal ligament on the outer surface of the furcation. Second molars were observed to have a higher number of canals than first molars (p<0.05), with maxillary second molars having a mean number of canals of 3.3, mandibular second molars having a mean number of canals of 3.5, maxillary first molars having a mean of 1.8, and mandibular first molars having a mean of 2.1 canals. No significant association was found between patient age and the number of canals present. Micro-Computed Tomography was an effective method to quantify accessory canals in the furcation region of extracted primary molars. / October 2016

Thesis (M.S.)--University of Michigan, 2005. / Includes bibliographical references.

Thesis (M.S.)--University of Louisville, 1995. / Typescript (Xerox copy). School of Dentistry, Department of Biological and Biophysical Sciences. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [84]-97).

Thesis (M.S.)--University of Louisville, 1995. / Typescript (Xerox copy). School of Dentistry, Department of Biological and Biophysical Sciences. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [84]-97).

Resumo: O objetivo dessa tese foi avaliar os efeitos da intrusão ortodôntica no processo de reparação de lesão de furca grau III em cães, e da presença de fator de necrose tumoral alfa (TNFα) e/ou interleucina-1 beta (IL-1ß) na mecanoresposta de células com característica de osteócitos e osteoblastos in vitro. No estudo in vivo, lesões de furca grau III foram criadas em pré-molares inferiores de sete cães. Após 75 dias, as lesões foram aleatoriamente tratadas com cirurgia a retalho (OFD) associada ou não à regeneração tecidual guiada (GTR) e enxerto ósseo autógeno (BA). Após um mês, iniciou-se a intrusão ortodôntica (I) em parte dos dentes tratados pelas duas diferentes abordagens (grupos teste), por meio de ancoragem em miniimplantes. Os cães foram sacrificados após três meses de movimentação e um mês de contenção. Todas as lesões de furca grau III foram reduzidas para grau II ou I nos grupos teste. O mesmo foi observado em 50% das lesões nos grupos controle (sem movimentação). O nível de inserção clínico foi reduzido nos grupos teste, no final da contenção (p<0.01). O grupo OFD+I apresentou maior preenchimento ósseo que os demais grupos (p<0.05), demonstrando superioridade desta associação, no tratamento de lesões de furca grau III, em cães. Esses resultados levantaram a hipótese de que o processo de degradação da membrana e/ou enxerto ósseo interagiria negativamente sobre o processo de reparo quando associado a forças ortodônticas, pois a presença de mediadores inflamatórios estaria intensificada. É conhecido que a alteração tecidual proveniente da movimentação ortodôntica é resultado da ação de mediadores químicos sobre as células dos tecidos periodontais. Portanto, buscamos avaliar in vitro a ação de duas citocinas pró-inflamatórias, TNFα e IL-1ß, sobre células ósseas em presença e ausência de carga mecânica. / Abstract: The aim was to assess the effects of orthodontic intrusion on the healing of class III furcation lesions in dogs, and of the presence of tumor necrosis factor alpha (TNFα) and/or interleukin-1 beta (IL-1ß) on the mechanoresponse of osteocyte and osteoblast-like cells in vitro. In the in vivo study, class III furcation lesions were created in lower pre-molars of seven mongrel dogs. After 75 days, teeth were randomly treated with open flap debridment (OFD) associated or not to guided tissue regeneration (GTR) and bone autograft (BA). After one month, teeth were randomly assigned to orthodontic intrusion using mini-implants anchorage or no movement. Dogs were sacrificed after three months of movement and one month contention. All class III furcations were closed or reduced to class II or I lesions in the intrusion groups while 50% of the class III lesions in non-moved teeth remained unchanged. Clinical attachment level was reduced in the intrusion groups by the end of contention (p<0.01). OFD + I presented smaller soft tissues area and larger bone tissue area than other groups (p<0.05). Orthodontic intrusion with mini-implants anchorage improved healing of class III furcation defects after OFD in dogs. Based on these results we hypothesized that degradation of membrane and/or bone autograft can negatively interfere on repair when associated to orthodontic movement because inflammatory mediators are intensified. It's known that cytokines are present during orthodontic movement which are acting on periodontal cells. Therefore we evaluated in vitro the effects of two pro-inflammatory cytokines, TNFα and IL-1ß, on bone cells in presence or absence of mechanical loading. / Orientador: Joni Augusto Cirelli / Coorientador: Rosemary Adriana Chiérici Marcantonio / Banca: Ana Cláudia Moreira Melo / Banca: Enilson Antonio Sallum / Banca: Ary dos Santos Pinto / Banca: Silvana Regina Perez Orrico / Doutor

Thesis (M.S.)--University of Louisville, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Louisville, 1998. / Includes bibliographical references.

The study objective was to determine cementum-dentin wall thickness along the furcation groove in maxillary bifurcated first premolars after preparation with three successively larger, 0.04 tapered, nickel titanium rotary files. Pre-instrumentation and post-instrumentation imaging was accomplished utilizing Cone Beam Computed Tomography. All data was analyzed using an ANOVA. Instrumentation resulted in a significant reduction in dentin-cementum wall thickness (p < .001). At mid-groove, predicted dentin-cementum wall thickness (95% CI) was equal to or less than the proposed standard (0.50 mm) for apical file sizes 30, 35, and 40 respectively. Instrumentation of the mid-groove in maxillary first premolars reduces dentin-cementum wall thickness to levels that may be insufficient to ensure tooth integrity.

BACKGROUND: The use of three-dimensional imaging has shown to provide advantages to the clinician in assessing bone morphology. The aim of this study will be to compare the diagnostic efficacy of cone beam computed tomography (CBCT) versus diagnostic clinical measurements in patients presenting with furcation involved maxillary first molars. METHODS: The study population included 20 patients with 34 maxillary first molar teeth with furcation involvement. Clinical horizontal and vertical probing measurements were compared to CBCT measurements taken by two calibrated examiners. RESULTS: Horizontal measurements showed a significant difference between Glickman class II and class III. There were no statistical significant differences with the horizontal measurements between clinical probing, bone sounding and CBCT measurements. CBCT vertical measurements were statistically greater than clinical probing measurements. CONCLUSION: The CBCT can provide similar horizontal measurements to standard clinical horizontal probing measurements and will provide a greater vertical dimension of a furcation defect to standard vertical probing measurements.

O objetivo desta pesquisa foi avaliar a reparação de defeitos de furca classe II em cães tratados com o retalho deslocado coronariamente, sozinho ou em associação com a regeneração tecidual guiada e o enxerto de tecido reparativo de alvéolos utilizando uma análise imuno-histoquímica. Os defeitos foram criados nos 2os, 3os e 4os pré-molares direitos e esquerdos mandibulares em quatro cães sem raça definida. No lado teste de cada cão, após a instrumentação radicular, os defeitos foram enxertados com o tecido reparativo, removidos de locais de extração dental com cinco dias de reparação. As áreas cirúrgicas foram recobertas com membranas absorvíveis e o retalho deslocado coronariamente suturado. No lado controle, após a instrumentação radicular, o retalho também foi deslocado coronariamente e suturado. Após 45 dias os cães foram sacrificados. As análises imuno-histoquímicas para osteonectina, osteopontina e sialoproteína óssea foram feitas no plano vestíbulo-lingual das furcas dos 3os pré-molares. As marcações imuno-histoquímicas foram similares entre os grupos demonstrando que eles provavelmente estavam em um estágio reparativo semelhante. / The aim of this research was to evaluate the repair of class II furcation defects in dogs treated with the coronally positioned flap alone or in association with guided tissue regeneration and post extraction tissue graft using an immunohistochemical analysis. The defects were created on the lower jaw right and left 2nd, 3rd and 4th premolars on four mongrel dogs. On the test side of each dog, after root instrumentation, the defects were grafted with a alveolar socket reparative tissue removed from five days healing teeth extraction sites. The surgical areas were covered with absorbable membranes and a coronally positionated flap was sutured. At the control side, after root instrumentation the coronally positionated flap was sutured. After 45 days, the dogs were sacrificed. The immunohistochemical analyses for osteonectin, osteopontin and bone sialoprotein were done on the bucal-lingual plane extent of the 3rd premolars furcations. The immunohistochemical expressions were similar among the two groups showing that they probably were in a similar healing stage.