Investigation of the effect of indirect pulp capping materials on dentin mineral density

Aim: To evaluate the potential of inducing mineral density changes of indirect pulp capping materials applied to demineralized dentin. Methods: A total of 50 cavities were prepared, 5 in each tooth, in extracted ten molars without caries, impacted or semi-embedded. The cavities were scanned by microcomputed tomography (µ-CT) after creating artificial caries by microcosm method (pre-treatment). Each cavity was subjected to one of 5 different experimental conditions: control (dental wax), conventional glass ionomer cement (Fuji IX GP Extra), resin-modified calcium silicate (TheraCal LC), resin-modified calcium hydroxide (Ultra-Blend Plus), MTA (MM-MTA) and the samples were kept under intrapulpal pressure using simulated body fluid for 45 days. Then, the second µ-CT scan was performed (post-treatment), and the change in dentin mineral density was calculated. Afterward, elemental mapping was performed on the dentinal surfaces adjacent to the pulp capping agents of 5 randomly selected samples using energy dispersive X-ray spectroscopy (EDS) apparatus attached to a scanning electron microscope (SEM). The Ca/P ratio by weight was calculated. Friedman test and Wilcoxon Signed Ranks test were used to analyze the data. Results: There was a significant increase in mineral density values of demineralized dentin after treatment for all material groups (p<0.05). Resin-modified calcium silicate had similar efficacy to MTA and conventional glass ionomer cement, but was superior to resin-modified calcium hydroxide in increasing the mineral density values of demineralized dentin. Conclusions: Demineralized dentin tissue that is still repairable can be effectively preserved using materials with remineralization capability

Cone beam computed tomography evaluation of the relationship between atlantodental interval and skeletal facial morphology in adolescents / Avaliação por tomografia computadorizada de feixe cônico da relação entre o intervalo atlantodental e a morfologia esquelética facial em adolescentes

Abstract Introduction: In the pediatric population, computed tomography examination of the upper cervical spine plays an important role in the diagnosis of neurological injuries involving that region. Due to the interconnected nature of the craniofacial structures, a structural change in one is expected to also cause changes in the other structures. Objective: The aim of this study was to evaluate relationships between atlantodental interval, cervical vertebral morphology, and facial structure in healthy adolescents using cone beam computed tomography. Methods: Thirty subjects aged 14-20 years (10 males, mean age: 17.2 years; 20 females, mean age: 17.9 years) were included in the study. The anterior, lateral and posterior atlantodental intervals, and vertical and anteroposterior dimensions of the first and second cervical vertebrae were evaluated from cone beam computed tomography images. Facial morphology was evaluated using 7 parameters on lateral cephalometric cone beam computed tomography images and 6 parameters on posteroanterior images. The Mann-Whitney U test and Wilcoxon test were used for statistical analyses. Results: Comparisons between males and females showed that most parameters were larger in males, with significant differences in vertical facial dimensions (anterior lower face height: p= 0.05; anterior upper face height: p= 0.001), (distance between the most internal point of the frontozygomatic suture and midsagittal reference plane; p= 0.01), (the distance between the deepest point of the right alveolar maxillar process and midsagittal reference plane; p= 0.001), and C2 vertebral dimensions. The anterior and lateral atlantodental interval values correlated with maxilla position relative to the mandible angle, and the anterior atlantodental interval correlated with lower anterior facial height (p= 0.05). Dimensional measurements of the C1 and C2 vertebrae were correlated with both anterior facial heights and some posteroanterior parameters. Conclusion: Sagittal, vertical, and transverse facial dimensions and positions were strongly associated with C1 and C2 vertebral dimensions, and the maxillomandibular relationship may affect atlantodental interval. Therefore, including craniofacial features in assessment of the atlantodental area and vertebral distances in adolescents may be beneficial.

Resumo Introdução: Na população pediátrica, a tomografia computadorizada da coluna cervical alta tem um importante papel no diagnóstico de lesões neurológicas que envolvem essa região. Devido à natureza interconectada das estruturas craniofaciais, espera-se que uma mudança estrutural em uma delas também cause alterações nas outras estruturas. Objetivo: Avaliar as relações entre o intervalo atlantodental, a morfologia vertebral cervical e a estrutura facial em adolescentes saudáveis com a tomografia computadorizada de feixe cônico. Método: Trinta indivíduos entre 14 e 20 anos (10 homens, média de 17,2 anos; 20 mulheres, média de 17,9 anos) foram incluídos no estudo. O intervalo atlantodental anterior, lateral e posterior e as dimensões vertical e anteroposterior da primeira e segunda vértebras cervicais foram avaliados a partir de imagens de tomografia computadorizada de feixe cônico. A morfologia facial foi avaliada utilizando-se sete parâmetros em imagens de tomografia computadorizada de feixe cônico cefalométricas laterais e seis parâmetros em imagens posteroanteriores. O teste U de Mann-Whitney e o teste de Wilcoxon foram utilizados para as análises estatísticas. Resultados: As comparações entre homens e mulheres mostraram que em sua maioria os parâmetros foram maiores no sexo masculino, com diferenças significantes nas dimensões faciais verticais (altura facial anterior inferior: p = 0,05; altura facial anterior superior: p = 0,001), distância entre o ponto mais interno da sutura fronto-zigomática e plano de referência médio-sagital; p = 0,01distância entre o ponto mais profundo do processo alveolar do maxilar direito e o plano de referência médio-sagital; p = 0,001) e as dimensões do corpo vertebral C2. O intervalo atlantodental anterior e lateral correlacionaram-se com o ângulo da posição da maxila em relação à mandíbula e o intervalo atlantodental anterior correlacionou-se com altura facial anterior inferior (p = 0,05). Medidas das dimensões das vértebras C1 e C2 foram correlacionadas com as alturas faciais anteriores e alguns parâmetros póstero-anteriores. Conclusão: As dimensões e posições faciais sagitais, verticais e transversais foram fortemente associadas às dimensões dos corpos vertebrais C1 e C2 e a relação maxilomandibular pode afetar o intervalo atlantodental. Portanto, incluir características craniofaciais na avaliação da área atlantodental e das distâncias vertebrais em adolescentes pode ser benéfico.

Evaluation of the sealing ability of different root canal sealers: a combined SEM and micro-CT study

Abstract Objective: The purpose of this study was to analyze the ability of multiple compounds to seal the dental tubules using scanning electron microscopy (SEM) and micro-computed tomogra-phy (micro-CT). Material and Methods: Twenty-four single-root human mandibular premolars were selected and instrumented with nickel-titanium rotary file and the final file size was #40/06. They were then randomly allocated into 2 groups, and all samples were filled with single cone gutta-percha (#40/06) and one of the tested sealers (AH Plus and EndoSequence BC sealers). All specimens were scanned using micro-CT and then three from each group were randomly selected for SEM analysis. Results: According to SEM, both root canal sealers showed sufficient adaptation to dentin along the whole length of the root canal, though the coronal sections presented superior sealing than the apical sections. Micro porosity analyses revealed that the volume of closed pores and the surface of closed pores had the largest values in the coronal sections, followed by the middle and the apical sections for both sealants (p<0.05). However, no significant difference was observed for those two parameters between AH Plus and EndoSequence BC sealers in any of the three sections (p>0.05), whereas they were larger in the apical section when the AH Plus sealer was used. Conclusions: By using the single cone technique, neither EndoSequence or AH Plus pro-vides a porosity-free root canal filling. The EndoSequence BC sealer may have similar sealing abilities regarding the whole root canal as the AH Plus sealer. A better sealing effect could be obtained in the coronal and middle sections of a root canal than the apical part by using the tested sealers.