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.

Introduction: The purpose of the study was to evaluate the effects of maxillomandibular advancement (MMA) surgery with counterclockwise rotation on soft tissue oral and nasal structures. Materials and Methods: This retrospective study included 34 subjects diagnosed with OSA who underwent MMA at the Stanford Sleep Clinic. Initial (T1) and Final (T2) CBCTs were evaluated and compared for 10 hard tissue and 15 soft tissue measurements. Additionally, the external nasal valve surface area was measured and compared between the two time points. A 3D superimposition was performed and used to evaluate the relative hard and soft tissue movements. Results: There was a linear correlation in the advancement of the maxilla to the sagittal movement of the upper lip of 75%, while the mandibular soft tissue moved 91-93% of the mandibular sagittal position. The interalar width and mouth width increased significantly following surgery while the lower vermillion border length decreased significantly. There was a clinically significant increase in the average surface area of the external nasal valve by 28%. No correlations were found between maxillary impaction and soft tissue oral or nasal measurements. Conclusion: MMA with CCW results in significant changes to the soft tissue nose and oral region. Soft tissue planning must be considered to maintain desirable esthetics following surgery.

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INTRODUCTION: Many studies have used different diagnostic methods to detect and measure the mental loop. Due to different criteria used and dissimilar diagnostic techniques diverse results were found in these studies. Understanding anatomical structures are crucial for planning and placing dental implants. Implant surgeons should be familiar with anatomical variations that they may encounter. METHODS: CBCTs of twenty male and twenty female patients were selected and categorized into four groups; male and female groups aged (18-44) and male and female groups aged (45-65). SIMPLANT Pro 17.01 software was used to determine the shape and the extension of the mental loop. Data was collected and analyzed for statistical significance to determine the association between CBCT findings and the patient's gender and age. RESULTS: The extension of the anterior loop of the metal nerve in this study ranged between 0 – 3.17mm. The mean of the loop was 1.25mm. The mental loops mean extension in males was 1.25mm. The mental loops mean extension in females was 1.23mm. The mental loops mean extension in elders was 1.19mm. The mental loops mean extension in younger group was 1.28mm. Subjects tend to have more curved mental loops compared to straight loops regardless the gender and/ or age group. CONCLUSION: In this study no association found between the shape and the extension of the mental loop with subjects age and gender. Measuring the extension of the mental loop should be mandatory for each individual to avoid injuries during implant placement in the interforaminal region.

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Bakgrund: Under en ortodontisk behandling med fast apparatur finns det en risk för att tänderna drabbas av rotresorption. Rotresorptioner kan mätas med hjälp av Cone Beam Computed Tomography (CBCT). Mätresultatet kan dock variera mellan olika observatörer och mätfel kan uppstå vilket påverkar metodens tillförlitlighet.Syfte: Att beräkna det mätfel som uppstår vid mätning av rotresorptioner som uppstår till följd av en ortodontisk behandling i CBCT-bilder och utvärdera mätmetodens tillförlitlighet. Metod: Tio ungdomar som genomgick ortodontisk behandling undersöktes med hjälp av CBCT-röntgen av båda käkar (tand 16-26 samt 36-46). Fem observatörer mätte tändernas rotlängd i utvalda CBCT-snitt. Studien omfattade 100 rötter från totalt 90 tänder. Mätningen upprepades av samma observatörer vid ett senare tillfälle. Tillförlitlighet utvärderades med intraklass-korrelationskoefficient (ICC 2.1) med 95% konfidensintervall. Mätfelet beräknades med Dahlbergs formel och standard moment of measure variance estimator (MME)-formel. Resultat: Tillförlitligheten mellan observatörer uppmättes till ICC = 0,88 under den första mätningen och ICC = 0,87 vid den upprepade mätningen. Inom observatörerna uppmättes tillförlitligheten till ICC = 0,84-0,92. Mätfelet uppmätt med Dahlbergs formel var 0,44-0,64 mm för samtliga tänder och observatörer. Det största mätfelet uppstod vid mätning av kuspider, 0,4-1,15 mm. Det minsta mätfelet uppstod vid mätning av molarer, 0,42-0,53 mm. Mätfelet vid mätning av premolarer och incisiver var 0,42-0,70 respektive 0,43-0,66 mm. När mätfelet beräknades med MME-formeln erhölls liknande resultat. Konklusion: Mätning av rotlängd i CBCT-bilder uppvisar hög reliabilitet inom och mellan olika observatörer. Precisionen varierar mellan olika tandgrupper och observatörer, men vid mätning av allvarliga rotresorptioner (>2 mm) är metoden pålitlig. CBCT anses vara en pålitlig metod för mätning av rotresorptioner som uppstått till följd av ortodontisk behandling. Vid studier där en mätning utförs bör reliabilitet och precision tas i beaktande. / Background: An orthodontic treatment may cause root resorption of varying extent on the involved teeth. The resulting root resorption can be measured in cone beam computed tomography (CBCT) images. However, measurement results may vary among different raters because of measurement errors, affecting the reliability of the method of measurement. Objectives: To evaluate reliability and precision of measurement of root length following orthodontic treatment in CBCT images. Methods: Ten adolescents participating in a trial of orthodontic treatment were examined with CBCT of both jaws. Five raters measured root length in preselected CBCT images of 100 roots from 90 teeth. The measurements were later repeated by the same raters. Reliability was expressed as intra-class correlation coefficient (ICC 2.1). Measurement error was calculated with Dahlberg’s formula and standard moment of measure variance estimator (MME)formula. Results: The inter-rater reliability for all raters had an ICC-value of 0,88 for the first measurement and an ICC-value of 0,87 for the second measurement. The intra-rater reliability for all raters had an ICC-value between 0,84-0,92. Measurement error calculated with the Dahlberg's formula ranged between 0,44-0,64 mm for all teeth for all raters. The largest difference of measurement error between raters was observed in canines, 0,44-1,15 mm. The smallest measurement error was observed in molars, 0,42-0,53 mm. Measurement errors calculated by the MME formula showed similar results. Conclusion: Root length measurements in CBCT-images show high intra- and inter rater reliability. The precision varies between raters and tooth groups but measurements of severe root resorptions (>2 mm) are reliable with this method. The reliability and precision of a method should always be considered when conducting measurement studies. CBCT could be considered a reliable method for measurement of root resorption following orthodontic treatment with different orthodontic appliances.

A cárie dentária continua sendo um grande desafio para os Cirurgiões-Dentistas pela dificuldade de diagnóstico, sobretudo em superfícies proximais. Muitos equipamentos se destinam a facilitar o exame do paciente, tendo como principal objetivo o diagnóstico de cáries incipientes. Dentre os exames mais utilizados está a radiografia interproximal associada ao exame clínico. O Sistema Internacional de Avaliação e Detecção de Cáries (ICDAS) vem sendo bem aceito tanto para o uso clínico como para pesquisas in vitro e in vivo, apresentando ótimos resultados. Além da técnica interproximal, a tomografia cone beam (CBCT) vem entrando no cotidiano da Odontologia, mas pouco se sabe sobre o seu desempenho para avaliação de cáries iniciais em superfícies proximais. A microtomografia (CT) é um novo método de avaliação destinado a pequenos espécimes e se assemelha a uma versão em miniatura da tomografia axial computadorizada, gerando imagens na ordem de micrômetros. Este método vem sendo utilização em pesquisas para se avaliar tecidos mineralizados, devido à sua habilidade de aferir com precisão o coeficiente de atenuação linear. O método padrão ouro que define com maior precisão os estágios da cárie é o histológico. Contudo, para sua avaliação é necessário destruir os espécimes. Este trabalho teve por objetivo avaliar o desempenho do método ICDAS, de radiografias digitais pela técnica interproximal, da CBCT e da CT para lesões precoces de cárie, com relação à histologia. Houve correlação entre os dados obtidos com o sistema ICDAS para superfícies proximais e as imagens da CT, no que diz respeito à classificação quanto à profundidade das lesões. A CT tem correlação positiva com a histologia tanto na classificação das lesões como na profundidade, contudo esta relação poderia ser maior se uma melhor resolução fosse conseguida. As radiografias digitais pela técnica interproximal tiveram o melhor desempenho com relação à CT e à histologia, sendo este desempenho muito semelhante ao método clínico ICDAS. A CBCT obteve o pior desempenho, contudo ainda assim houve correlação positiva com a histologia e com a CT. A associação do método clínico ICDAS e as radiografias interproximais digitais tiveram o melhor desempenho com relação à histologia. A grande vantagem da microtomografia quando comparada a outros métodos de avaliação da doença cárie, é a manutenção da integridade dos espécimes, a informação tridimensional e isotrópica, possibilitando o uso dos espécimes em outro momento, sem a perda de eventuais características presentes nos mesmos. / Dental caries is still a great challenge to dentists, manly in proximal surfaces due to its difficult diagnosis. Many types of equipment have been designed to minimize this problem, specially aiming early caries detection. Among all, one of the most used by clinicians is the interproximal radiograph. The International Caries Assessment System (ICDAS) is a clinical evaluation method that is well accepted and used having a good performance not only for in vivo but also for in vitro studies. Cone beam CT (CBCT) is also being assessed in the overall Dentistry, but its performance on early caries detection has not extensively being evaluated. Microtomography (CT) is a new assessment method which is addressed to small specimens and is similar to a miniature version of axial computed tomography, producing images with micrometrical definition. CT is being assessed in dental research to evaluate mineral content of hard tissues, due to its ability to measure precisely the linear attenuation coefficient. The gold standard method to measure early caries lesions is histological method. However, to perform it, its necessary to cut the specimen. This study had the aim to evaluate the ICDAS, digital X-rays with the interproximal technique, CBCT and CT performance for early caries lesions, when compared to histology. ICDAS for proximal surfaces and CT had a positive correlation through the lesions depth. CT had a positive correlation with histology when analyzing lesions depth and the classification relating to the severity of the lesion, although this relation could be better if a better resolution could be achieved. Digital bite-wing radiographs had the best performance among all exams when comparing to CT and histology, similar to what we notice with the ICDAS results. CBCT had the worst results when comparing to CT and histology, but it was still considered a good relation. The best performance was achieved with the association of ICDAS and digital bite-wing radiographs when comparing to histology. The great advantage of CT when compared to other validating methods to evaluate dental caries is that it doesnt destroy the specimens, it gives tridimensional and isotropic information, making possible to use the specimens again, without losing inner properties.