Orientadores: Deborah Queiroz de Freitas França, Gláucia Maria Bovi Ambrosano / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-26T13:33:44Z (GMT). No. of bitstreams: 1 Bezerra_IlanaSanamaikaQueiroga_D.pdf: 1698292 bytes, checksum: 997da55ad95075c898e9eae4519d6525 (MD5) Previous issue date: 2014 / Resumo: O objetivo neste trabalho foi verificar a influência da ferramenta para redução de artefato (FRA) na qualidade da imagem e no diagnóstico de FRVs, em dentes com pino metálico intracanal. A amostra foi composta por trinta dentes unirradiculares, que tiveram suas coroas removidas e seus canais instrumentados. Do total, foram induzidas fraturas completas e incompletas em vinte raízes e ao final, todas as raízes foram divididas em três grupos: controle (n=10), fratura radicular completa (n=10) e fratura radicular incompleta (n=10). Cada raiz recebeu um pino metálico intracanal e foi escaneada duas vezes no tomógrafo Picasso Trio 3D® (Vatech, Hwaseong, Coreia do Sul): uma sem e uma com o emprego da FRA. As imagens foram avaliadas objetiva e subjetivamente. A avaliação objetiva foi feita no ImageJ (NIH, Bethesda, MD, EUA), em uma região de interesse circular padronizada, na qual foram mensuradas os valores médios e a variação dos tons de cinza e a taxa contraste-ruído (TCR) nas imagens com e sema FRA. A avaliação subjetiva foi realizada de duas formas: inicialmente, cinco avaliadores (cirurgiões-dentistas, especialistas em Radiologia Odontológica) treinados analisaram as imagens no software EZ3D quanto à presença de FRV, utilizando uma escala de cinco pontos: Posteriormente, um avaliador quantificou os artefatos formados. Foram avaliados o cupping, as bandas hipodensas e as estrias hiperdensas. A imagem obtida com FRA foi comparada à sua respectiva sem FRA para atribuição de um dos três escores: (0) não houve mudança na quantidade de artefato formado; (1) houve diminuição e (2) houve aumento. As concordâncias intra e interexaminador foram avaliadas pelo teste Kappa ponderado. A comparação dos resultados do diagnóstico de FRV com o padrão-ouro foi realizada pela curva ROC (Receive Operating Characteristic). Além disso, também foram calculados os valores de sensibilidade, especificidade e acurácia. A comparação dos resultados da análise objetiva, dos valores das áreas sob a curva ROC e dos testes de diagnóstico nas aquisições com e sem a FRA foi realizada por meio do Teste t. A presença de artefatos foi avaliada por análise descritiva. Os resultados mostraram diminuição significativa dos valores médios dos tons de cinza (p=0,002) e da TCR (p=0,000) com utilização da FRA. Quanto à avaliação subjetiva, os valores das áreas sob a curva ROC, sensibilidade, especificidade e acurácia também foram inferiores com a utilização da FRA, sendo os dois últimos estatisticamente significativos, para os casos de fratura incompleta (p=0,028 e p=0,037, respectivamente) e fratura completa (p=0,021 e p=0,031, respectivamente). Em relação aos artefatos avaliados, de uma maneira geral houve diminuição dos mesmos nas imagens com FRA. Dessa forma, concluiu-se que a utilização da FRA causou uma diminuição nos artefatos formados, porém não houve não houve melhora na qualidade da imagem avaliada de maneira objetiva nem repercussão no diagnóstico de FRVs em raízes com pino metálico intracanal, uma vez que o mesmo foi prejudicado / Abstract: This study aimed to verify the influence of the artifact reduction algorithm in the image quality and the diagnosis of VFR. The sample was composed of thirty single-rooted teeth, which the crown was removed and the root canal was prepared. In twenty roots, fractures were induced. The roots were divided into three groups: control (n=10), complete (n=10) and incomplete (n=10) VRF. In each root canal it was inserted a well-fitted metal post and it was scanned in the Picasso Trio 3D® CBCT device (Vatech, Hwaseong, South Korea) with and without the artifact reduction algorithm. The images were evaluated objective- and subjectively. The objective evaluation was performed in the ImageJ software (NIH, Bethesda, MD, USA), by a standard round region of interest, on which it was measured the mean value of the grey level and contrast-to-noise ratio (CNR). Five observers (oral radiologists) performed blindly the subjective evaluation in EZ3D software to diagnosis VRF, which was classified according to a 5-point scale. Posteriorly, one observer quantified the presence of the beam hardening artifacts. It was evaluated the cupping artifacts, hypodense halos and streak artifacts. The images with and without the artifact reduction algorithm was compared according three scores: no change, increase or decrease of the beam hardening artifact. The intra- and interobserver agreement were calculated by the weighted-Kappa test. The ROC (Receiver Operating Characteristic) curve was used to compare the diagnosis of VRF and the gold standard. Also, the sensitivity, specificity and accuracy were obtained. The comparison of the grey levels and the CNR were performed by the t-Test. The production of beam hardening artifacts was descriptive analyzed. The results showed a significant decrease of the grey level (p=0,002) and CNR (p=0,000) with the artifact reduction algorithm. The ROC curve values, sensitivity, specificity and accuracy were lower with the artifact reduction algorithm for the diagnosis of VRF. It was observed a statistically significant difference in the specificity and accuracy. Regarding to the quantity of the beam hardening artifacts, it was observed an overall reduction in images with the artifact reduction algorithm. In conclusion, the use of the artifact reduction algorithm produced a decrease of the beam hardening artifacts; however, it was observed negative influence in image quality and in the diagnosis of VRF in the presence of metal post / Doutorado / Radiologia Odontologica / Doutora em Radiologia Odontológica

Magister Scientiae Dentium - MSc(Dent) / Autologous bone grafting in conjunction with dental implant therapy is a well-accepted procedure in oral and maxillofacial rehabilitation. A variety of intraoral donor sites, such as the mandibular symphysis, the mandibular ramus and the maxillary tuberosity have been used in oral and maxillofacial reconstruction. However these sites are associated with complications. In order to reduce these complications, the anterior palate has been proposed as a potential donor site. However, the scientific literature in this regard is sparse, and larger studies are required to investigate the clinical potential of this proposed site. Aim: To determine the volume and density of available bone in the anterior palate that may be used for bone harvesting using cone-beam computed tomography (CBCT) in a select South African population. Materials and methods: One hundred previously acquired CBCT scans taken at the Diagnostic and Radiology Department of Tygerberg Oral Health Centre were analyzed for the required data. These were all acquired from a single CBCT machine (Newtom VGI®, Verona, Italy). The study sample included 52 females and 48 males ranging from ages 20 years to 80 years. The CBCT scans were divided into 3 different age groups. The first age group was between the ages of 20 and 39 years, the second age group was from 40 to 59 years and the third age group was ≥ 60 years. The volume and density of the anterior palate of the different age groups were analyzed using specific criterion. CBCT specific software (Simplant Pro Crystal®) Dentsply implants, Mannheim, Germany was used to standardize the data collection. All data was stored in a Microsoft Excel spreadsheet (Microsoft Corporation, Washington, USA). Results: The mean volume of the anterior palate in this study was 2.11 ± 0.55 cm3, with a minimum volume of 1.04 cm3 and a maximum volume of 3.82 cm3. There was no significant difference in the volume and density of the anterior palate between different age groups and no significant difference in the volume between males and females (p value = 0.227). Conclusions: The anterior palate affords a considerable amount of bone volume which is similar or even more than other intraoral donor sites. The anterior palate is a potential donor site for bone harvesting and CBCT may be regarded as an ideal tool to analyze the amount of bone available for harvesting.

Orientador: Frab Norberto Bóscolo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-27T04:09:35Z (GMT). No. of bitstreams: 1 Ramirez-Sotelo_LauraRicardina_D.pdf: 1681017 bytes, checksum: 948bf57afd3cf56354df233fedc8eafe (MD5) Previous issue date: 2015 / Resumo: Métodos têm sido propostos para analisar a articulação temporomandibular, com o intuito de avaliar as estruturas nesta região, principalmente em indivíduos com padrões esqueléticos diferentes, pois o tratamento ortodôntico realizado, neste grupo de indivíduos, pode trazer consequências diretas na morfologia e função articular. Neste estudo, comparou-se as regiões medial central e lateral da ATM de indivíduos com padrão esquelético I, II e III, pelas medidas relação da cabeça da mandíbula com a fossa mandibular, inclinação da vertente posterior da eminência articular e altura da eminência articular. Foram avaliadas as imagens de tomografia computadorizada de feixe cônico de 95 indivíduos com padrões esqueléticos I (N=36), II (N=31) e III (N=28). Três examinadores independentes avaliaram as imagens da articulação temporomandibular, na região lateral central e medial, em dois momentos diferentes. Houve correlação inter e intraexaminador de satisfatória a excelente para todas as medidas avaliadas em cada região da articulação e nos três tipos de padrão esquelético. Não houve diferenças estatísticas significativas na relação entre a cabeça da mandíbula com a fossa mandibular, nem na inclinação da vertente posterior e altura da eminência articular entre os padrões esqueléticos estudados em nenhuma das regiões. As medidas apresentaram diferença estatística significativa entre a região central, lateral e medial em cada tipo de padrão esquelético I, II e III, exceto a medida da inclinação da vertente posterior da eminência articular para indivíduos de padrão esquelético I no lado direito (p?0,05). Houve diferença estatística entre ambos os lados para as medidas da inclinação da eminência na região central do grupo de padrão esquelético I e para a medida do espaço articular anterior em todas as regiões e todos os padrões esqueléticos (p?0,05). Concluiu-se que não há influência do padrão esquelético I, II, III na relação da cabeça da mandíbula com a fossa mandibular, inclinação da vertente posterior e altura da eminência articular nas regiões estudadas em nenhuma das regiões estudadas. E a avaliação desses mesmos parâmetros ósseos em indivíduos com padrões esqueléticos I, II e III devem ser realizados em diferentes regiões, já que o corte central nem sempre representa a relação óssea da articulação em toda a sua extensão / Abstract: Methods have been proposed to analyze the temporomandibular joint, in order to evaluate the structures of this region particularly in individuals with different skeletal patterns, since the orthodontic treatment performed in this group of people can bring direct effect on the morphology and joint function. This study evaluated the relationship between the mandibular condylar process - mandibular fosse, the slope of the posterior slope and the height of the articular eminence in medial regions, central and lateral temporomandibular joint of individuals with skeletal patterns I, II and III. Were evaluated computed tomography cone beam of 95 patients with skeletal patterns I (N = 36), II (n = 31) and third (N = 28). Three independent observers evaluated the images of the temporomandibular joint, the lateral, central and medial region, at two different times. There was correlation, inter and intra-rater, from satisfactory to excellent for all measures evaluated in each region of the joint in the three types of skeletal pattern evaluated. There were not statistically significant differences in the relation between the mandibular condylar process and the mandibular fosse or the slope of the posterior slope and the height of the articular eminence in any of the regions between the studied skeletal patterns. The measures showed statistically significant differences between the central, lateral and medial in each type of skeletal pattern I, II and III, except the measure of the slope of the posterior slope of the articular eminence in skeletal pattern I on the right side (p?0,05). There was statistical difference between measures, of both sides, of the slope of the eminence in central skeletal pattern of group I, and for the measure of the previous joint space in all regions and all skeletal patterns (p = 0.05). It was concluded that there is no influence of the skeletal pattern I, II, III in respect of the mandibular condylar process with the mandibular fosse, posterior slope of the slope and height of the articular eminence in the regions studied in any of the studied regions. And the evaluation of the same bone parameters in subjects with skeletal patterns I, II and III should be conducted in different regions, as the central court is not always the bone of the joint relationship in all its extension / Doutorado / Radiologia Odontologica / Doutora em Radiologia Odontológica

Orientador: Solange Maria de Almeida Boscolo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-27T15:58:05Z (GMT). No. of bitstreams: 1 Verner_FrancielleSilvestre_D.pdf: 3297356 bytes, checksum: 3989155d7f53d24a1147b56f4abedc69 (MD5) Previous issue date: 2015 / Resumo: As características dentárias podem influenciar diretamente na determinação da morfologia da eminência articular (EA). Entretanto, até o presente momento, os estudos se restringiram a correlacionar a morfologia da EA com perdas dentárias e má-oclusões. Neste contexto, torna-se importante a realização de estudos que estabeleçam uma possível correlação entre a morfologia dos arcos dentais e da EA em pacientes que não apresentem alterações oclusais ou ausências dentárias. O objetivo no presente estudo foi avaliar a correlação entre a morfologia do arco dental e da EA por meio de tomografia computadorizada de feixe cônico (TCFC). Foram utilizadas imagens de 60 pacientes, sem ausências dentárias ou alterações oclusais, e que apresentassem Classe I de Angle. As imagens foram avaliadas por três especialistas em Radiologia Odontológica, instruídos a realizar mensurações da altura (EAh) e inclinação da EA (ângulos 'alfa' e 'beta'), nas regiões centrais, laterais e médias, e inclinação da parede lateral da fossa mandibular (ângulo 'sigma'). Foram avaliadas as medidas da largura, profundidade e perímetro dos arcos dentários superior e inferior. Posteriormente, os arcos foram classificados quanto às formas cônica, quadrangular e ovoide. Após 30 dias 10% da amostra foi reavaliada, para cálculo do índice de correlação intraclasse (ICC). Foram obtidas as médias e desvio-padrão das mensurações realizadas na EA e nos arcos dentais, em cada uma das formas encontradas, que foram comparadas por meio da análise de variância (ANOVA) um fator e teste de 'Tukey'. Para verificar a correlação entre os arcos e a EA foi calculado o coeficiente de Correlação de Pearson. A influência das medidas dos arcos nas medidas da EA foi determinada por meio de regressão linear. O nível de significância foi de 5%. O ICC variou de satisfatório a excelente. Para a EA, o ângulo 'beta' na forma ovoide foi diferente no corte central do lado direito e em todos os cortes do lado esquerdo. O ângulo 'alfa', também na forma ovoide, diferiu no corte central direito e lateral esquerdo. E o ângulo 'sigma' no corte central esquerdo entre as formas quadrangular e ovoide. Na forma cônica observaram-se o maior número de correlações, seguida das formas ovoide e quadrangular. A altura da EA foi a característica mais correlacionada às medidas dos arcos. Os perímetros dos arcos superiores e inferiores influenciaram a altura da EA no lado esquerdo. No arco inferior, IC influenciou 'alfa' e 'beta' dos lados direito e esquerdo, IL influenciou 'alfa' do lado direito, 2PM influenciou 'alfa' do lado esquerdo e 'beta' dos lados direito e esquerdo, e 1M influenciou 'alfa' do lado direito. No arco superior, IC influenciou a altura da EA do lado esquerdo. Pode-se concluir que houve correlação entre as diferentes características dos arcos dentais com a morfologia da eminência articular. A forma cônica apresentou maior número de correlações e, portanto, modificações nas características dos arcos cônicos podem representar maior potencial em gerar alterações morfológicas na eminência articular / Abstract: The dental features can directly influence in determining the morphology of the articular eminence (EA). However, to date, the studies have been restricted to correlate EA morphology with dental losses and malocclusions. In this context, it is important to conduct studies to establish a possible correlation between the dental arches and EA morphology in patients with no occlusal alterations or missing teeth. The aim in this study was to evaluate the correlation between dental arch and articular eminence (AE) morphology by cone beam computed tomography (CBCT). Three dental radiologists analyzed images from 60 patients without dental absences neither occlusal alterations, and classified as Class I of Angle. The images were evaluated by three oral radiologists, and the height (AEh), the slope of AE ('alpha' e 'beta' angles), at central, lateral and medial positions, and lateral inclination ('sigma' angle) of mandibular fossae were measured. The measures of width, depth and perimeter of maxillary and mandibular arches were evaluated. Then, the arches were subjectively classified according to tapered, squared and ovoid shapes. After 30 days, 10% of the sample was reevaluated. Mean and standard deviation of the measures in AE and dental arches were obtained in each shape, and compared by ANOVA (one way) and "Tukey" test. To verify the correlation between arches and AE, the Pearson Correlation coefficient was calculated. The influence of arches' measures on AE's measures was determined by linear regression. The level of significance was 5%. For dental arches, the measures of depth and perimeter of square arches were different from the other shapes, in both arches. The measures CI and 2PM were different on upper and lower arches, respectively, between the tapered and square shapes. For the AE, the 'beta' angle on the ovoid shape was different on central slice on the right side and on all slices on the left side. The 'alpha' angle, also on the ovoid shape, differed on central right slice and lateral left. And the 'sigma' angle on central left slice between square and ovoid shapes. In general, the measures in men were higher than in women, but only the 'beta' angle on medial right slice, the measures C, 2PM, 1M and perimeter from upper arch, and 1PM and PM from lower arch, showed significant differences. On the tapered shape, there was the highest number of correlations, followed by ovoid and square shapes. The height of AE was the most correlated feature to the measures of the arches. The perimeter of the upper and lower arches influenced on the height of the AE on the left side. On lower arch, CI influenced 'alpha' and 'beta' on both sides, IL influenced 'alpha' on the right side, 2PM influenced 'alfa' on the left side and 'beta' on both sides, and 1M influenced 'beta' on the right side. On the upper arch, CI influenced the height of the AE on the left side. It can be concluded that there was correlation between the different features of the dental arches with the AE morphology. The tapered shape showed a higher number of correlations and, therefore, changing in the features of the tapered arches may represent greater potential in generating morphological changes in the AE / Doutorado / Radiologia Odontologica / Doutora em Radiologia Odontológica

Orientador: Deborah Queiroz de Freitas França / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-28T02:05:09Z (GMT). No. of bitstreams: 1 Queiroz_PolyaneMazucatto_M.pdf: 2757992 bytes, checksum: 06e73a8b08ccb2c9d71f5790996c28cb (MD5) Previous issue date: 2015 / Resumo: Materiais de alta densidade física e alto número atômico quando presentes no objeto escaneado podem resultar em artefato nas imagens tomográficas. O artefato compromete a qualidade da imagem tomográfica, podendo inviabilizar o uso dessa modalidade de diagnóstico. Com este trabalho, teve-se dois objetivos: avaliar a ação da ferramenta de redução de artefato metálico (RAM) nas imagens tomográficas de phantoms com diferentes materiais utilizados na Odontologia (amálgama de prata, guta-percha e liga metálica) e avaliar a influência de diferentes tamanhos de campo de visão (field of view - FOV) e de voxel sobre a ação da ferramenta. Foram confeccionados três phantoms de resina acrílica com amostras dos materiais estudados em seu interior. Os phantoms foram escaneados no tomógrafo do aparelho Picasso Trio® (Vathec, Hwaseong, Coréia do Sul) com diferentes FOVs (120x85 mm, 80x80 mm, 80x50 mm e 50x50 mm) e voxels (0,3 mm e 0,2 mm). Todos os escaneamentos foram realizados duas vezes com cada parâmetro, uma sem ativação e uma com ativação da ferramenta de RAM. As imagens foram avaliadas no programa OnDemand3D (CyberMed, Seul, Coréia do Sul). Foram obtidos valores de média e desvio-padrão do histograma das áreas ao redor das amostras e das áreas-controle e foi calculada a relação contraste-ruído (RCR). Os dados foram submetidos à análise. Observou-se influência positiva da ferramenta nos valores do desvio-padrão das áreas ao redor das amostras dos materiais amálgama de prata e liga metálica. Não houve influência da utilização da ferramenta sobre os valores das médias e valores de RCR. Na presença da ferramenta de RAM, o FOV e o voxel não influenciaram os valores de desvio-padrão das áreas ao redor das amostras. Foi possível concluir que a ferramenta mostrou-se eficaz na redução do artefato gerado pelo amálgama de prata e pela liga metálica; e a ação da ferramenta não é influenciada por diferentes FOVs e voxels, de forma que esses parâmetros podem ser selecionados de acordo com o objetivo do exame, sem haver alterações quando a ferramenta é utilizada / Abstract: High density and high atomic number materials are scanned results in artefact in tomographic image. The artefact compromises the quality of tomographic image, which may make the image useless for the diagnosis. The aim of this study were: to assess the action of metal artefact reduction (MAR) algorithm on tomographic images of phantoms with different materials used in Dentistry (dental amalgam, gutta-percha and dental alloy); to assess the influence of different sizes of field of view (FOV) and voxel on the action of the MAR algorithm. Three phantoms were made of acrylic resin with the dentals materials in their interior. The phantoms were scanned on Picasso Trio® machine (Vathec, Hwaseong, South Korea) with different FOVs (120x85 mm, 80x80 mm, 80x50 mm and 50x50 mm) and voxels (0.3 mm and 0.2 mm). All scans were performed twice with each parameter, without and with activation of the MAR algorithm. The images were evaluated on the OnDemand3D software (CyberMed, Seoul, South Korea). The mean and variation (standard deviation - SD) of greyscale values of the histogram of the areas around samples and control areas were obtained. The contrast-to-noise ratio (CNR) was calculated. Data were statistically analyze. There was positive influence of the algorithm on the SD of the areas around the samples of dental amalgam and dental alloy. There was no influence of the algorithm on the mean of greyscale values and CNR. The FOV and voxel did not influence the SD of the areas around the samples when the MAR algorithm was active. In conclusion, the MAR algorithm showed positive effect in reducing the artefact caused by dental amalgam and dental alloy; its action was not influenced by different FOVs and voxels, so those parameters can be selected according to the examination purpose, as there are no changes in the algorithm use / Mestrado / Radiologia Odontologica / Mestra em Radiologia Odontológica

A tomografia computadorizada, ferramenta de diagnóstico indispensável na rotina médica, tem seu emprego justificado por proporcionar imagens com alto padrão de qualidade e sem sobreposição de estruturas e distorções, porém sua utilização tem sido limitada, principalmente devido ao alto custo e à alta dose de radiação ao paciente. Um novo tipo de tomografia computadorizada, que utiliza o princípio do feixe cônico, foi desenvolvido para obtenção de imagens com alto padrão de qualidade, menor dose de radiação, menor custo e aplicação na Odontologia, uma vez que obtém imagem de áreas pequenas. O objetivo deste trabalho foi realizar um estudo comparativo entre o canal anatômico e o canal cirúrgico de vinte primeiros pré-molares inferiores utilizando o tomógrafo NewTom. Para tanto foram obtidas três imagens de cortes axiais tomográficos do canal anatômico e três do canal cirúrgico de cada dente, utilizando o QR-DVT 9000 software. Os resultados mostraram que a metodologia aplicada foi capaz de identificar medidas maiores do canal cirúrgico em relação ao anatômico. Conclui-se que este novo tipo de tomografia pode ser indicado para estudos que envolvem a morfologia do canal radicular. / Computed tomography, a very important tool in medical diagnostical routine, has been used due to the high quality images it produces, without double images or distortions however its utilization has been restricted due to the high costs and the high levels of radiation that the patient is exposed. A modern type of computed tomography, that uses the cone been was developed to obtain high quality images, less radiation exposition, less costs and odontology applications, because it can obtain images of small areas. The objective of this research is to compare the anatomic root canal and the surgical root canal of twenty lower premolars. To do this it was obtained three images of the axial slices of the anatomic root canal and three images of the surgical root canal of each tooth, using the QR-DVT 9000 software (NewTom 3G). The results shown bigger measures of the surgical root canal comparing to the anatomic root canal. Therefore this new model of tomography can be indicated to morphologic study of the root canal.

El retratamiento de canales radiculares es una alternativa ante el fracaso endodóntico. Este procedimiento tiene como objetivo reducir los síntomas que pueden presentarse o agravarse posterior al tratamiento de endodoncia. El procedimiento del retratamiento de canales sigue la premisa que aparentemente la calidad del material de obturación en todo el sistema de canales es deficiente, por consiguiente, todo el material debe ser retirado. Actualmente, con mejores técnicas de análisis imagenológico es posible identificar el origen de la lesión apical, por lo tanto, es posible seleccionar los canales pulpares con tratamiento deficiente y poder ser tratados de forma individual. De esta manera, el retratamiento selectivo de canales podría evitar el desgaste innecesario de canales en buen estado. / Root canal Retreatment is an alternative in the face off endodontic failure. This procedure aims to reduce the symptoms that may occur or worsen after the endodontic treatment. The root canal retreatment procedure follows the premise that apparently the quality of the filling material in the entire canal system is deficient, therefore, all the material must be removed. Currently, with better techniques of image analysis it is possible to identify the origin of the apical lesion, therefore, it is possible to select the pulp canals with poor treatment and be able to treat them individually. In this way, the selective root canal retreatment could avoid the unnecessary wear of root canals in good condition. / Trabajo académico

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: In order to successfully treat an infected root canal system (RCS), it is required to locate all root canals and have an access path to the apex of each canal. This can be challenging in teeth with pulp canal obliteration (PCO), often leading to increased chair time and increased risk of iatrogenic errors. Guided endodontic access (GEA) combines information from a cone-beam computed tomography (CBCT) scan with an intra-oral scan to create a stent. GEA stents with or without fixation pins have been shown to be successful in accurately negotiating a RCS with PCO. Objective: Compare the degree of deviation and difference in 3D offset at the base to apical tip of the drill from the designed access path when a GEA stent with and without pin fixation is used to access tooth #8 with PCO. Materials and Methods: A 3-D printed maxillary model of an anonymous patient had a GEA stent designed using coDiagnonstiX software. The stent extended from tooth #3 to tooth #14 with the guide sleeve over tooth #8. Tooth #8 with no calcification, calcification to the cervical third, and calcification to the middle third of the RCS were designed in the coDiagnostiX software. Tooth #8 will be accessed using a 1.3 mm drill that fits a 1.3 mm sleeve used for both access and pin fixation. 15 of the 30 GEA samples will utilized pin fixation, while the other 15 samples did not utilize pin fixation. Following GEA in all 30 samples a CBCT was taken of each sample. Each post-operative CBCT was aligned with the pre-operative CBCT in the coDiagnostiX software. The coDiagnostiX software was able to calculate the degree of deviation and difference in 3D offset between the base and apical tip of the drill during GEA. Paired t-tests were used to test each group for significant differences in 3D offset between base and tip. Two-way ANOVA was used to evaluate the effects of pin fixation and calcification on the degree of deviation and the deviation of 3D offset of the entry point and tip. Results: There was a significant interaction between use of pin fixation and calcification level on the degree of deviation of GEA. GEA with pin fixation had a significantly larger degree of deviation than GEA without pin fixation with calcification extending to the middle third of the RCS. GEA with and without pin fixation did not have a significant difference when calcification extended to the cervical third of the RCS or no calcification was present. There was a significant interaction between use of pin fixation and calcification level on 3D offset difference. GEA with pin fixation had a significantly larger 3D offset difference than GEA with no pin fixation for calcification in the middle third of the RCS. For GEA with and without pin fixation there was no significant difference when calcification extended to the cervical third of the RCS or no calcification was present. Conclusion: The use of pin fixation did not result in a decrease of degree of deviation or difference in 3D offset during GEA access. It can be concluded that the use of pin fixation is not necessary for GEA of teeth with PCO when a full dentition is present to provide stability and retention of the stent. / 2022-06-21

Magister Scientiae Dentium - MSc(Dent) / Previously, many studies have used cone beam computed tomography (CBCT) to detect and confirm the exact location of the MB2 canal in maxillary molars. It is now considered the gold standard, as it allows clinicians to visualize complex anatomical structures and to perform endodontic treatment safely. However, in the context of this study, the prevalence and location of the MB2 in maxillary first and second permanent molars among the Libyan population is limited. The aim of this in vivo study is to describe the prevalence and location of the MB2 in the mesiobuccal root of first and second maxillary molars and to describe a methodology to enable its geometric location in the Libyan population using CBCT imaging.

Evaluar la dimensión antero- posterior (A-P)/medio-lateral (M–L), y la morfología del cóndilo mandibular en pacientes de 18 a 65 años con patrón esquelético Clase I en tomografías computarizadas Cone Beam. Material y Métodos: 71 tomografías fueron evaluadas mediante el software RealScan 2.0. La dimensión fue determinada por los puntos A (más anterior en el plano sagital), P (más posterior en el plano sagital), M (más interno en el plano coronal), L (más externo en plano coronal). Se evaluó la morfología del cóndilo en dos planos coronal y sagital, clasificándose en: redonda, aplanada, convexa y mixta. La dimensión del cóndilo fue analizada por estadística descriptiva y la morfología mediante distribución de frecuencias. Para el análisis bivariado, se aplicó la prueba de t de Student. Resultado: Se obtuvieron las medidas del diámetro A-P del cóndilo derecho (CD) (8,72mm ± 1,25mm) y el izquierdo (CI) (8,50mm ± 1,50mm), el diámetro M-L del CD (19,24mm ± 2,03mm) y el CI (18,97mm ± 1,87mm). Hubo diferencias significativas en la dimensión M-L del CI del sexo masculino en comparación al femenino (p=0.002). La morfología más prevalente del CD (35,21) y CI (23,94) en plano coronal fue de tipo redonda. Conclusión: La dimensión A-P del cóndilo derecho e izquierdo es similar en ambos sexos; sin embargo, existen diferencias en la dimensión M-L del cóndilo izquierdo del sexo masculino. La morfología del cóndilo derecho e izquierdo más prevalente fue la redonda en plano sagital a excepción del plano coronal. / To evaluate the anterior-posterior (A-P)/medial-lateral (M-L) dimension, and morphology of the mandibular condyle in patients aged 18 to 65 years with Class I skeletal pattern on Cone Beam Computed Tomography scans (CBCTs). Materials and Methods: Seventy one CBCTs were evaluated using RealScan 2.0 software. The dimension was determined by points A (most anterior in the sagittal plane), P (most posterior in the sagittal plane), M (most interior in the coronal plane), L (most exterior in the coronal plane). The morphology of the condyle was evaluated in two coronal and sagittal planes, being classified as: round, flat, convex or mixed. The size of the condyle was analyzed by descriptive statistics and the morphology by frequency distribution. For the bivariate analysis, the Student’s t-test was applied. Results: Measurements were obtained for the A-P diameter of the right condyle (RC) (8.72mm ± 1.25mm) and the left condylar (LC) (8.50mm ± 1.50mm), the M-L diameter of the RC (19.24mm ± 2.03mm) and the LC (18.97mm ± 1.87mm). There were significant differences in the male M-L dimension of the LC compared to the female (p=0.002). The most prevalent morphology of RC (35.21) and IQ (23.94) in the coronal plane was round.. Conclusion: The A-P dimension of the right and left condyle is similar in both genders; however, there are differences in the M-L dimension of the left male condyle. The most prevalent morphology of the right and left condyle was round in the sagittal plane with the exception of the coronal plane. / Revisión por pares