Effect of gutta-percha solvents on fiberglass post bond strength to root canal dentin.

The purpose of this study was to investigate the influence of gutta-percha solvents on the bond strength of fiberglass post to root canal dentin. Forty bovine incisors were decoronated, prepared, filled, and randomly distributed into four groups (n = 10) according to the gutta-percha solvent used: control, xylene, eucalyptol and orange oil. After root canal treatment, the posts were cemented into the prepared root canals using a resin-based cement. A micro push-out test was executed, and the patterns of failure were assessed with microscopy. The data were analyzed using two-way ANOVA followed by Tukey's test. The control group exhibited greater bond strength compared to the eucalyptol group in the cervical and middle thirds of the root (P < 0.05); however, it did not differ significantly from the xylene and orange oil groups (P > 0.05). No difference was observed in the values of the xylene, orange oil, and eucalyptol groups (P > 0.05). The cervical third had higher values than the apical third for all tested solvents (P < 0.05). Adhesive failure between resin cement and dentin was the most frequent type of failure. The use of xylene and orange oil as gutta-percha solvents did not influence the bond strength of fiberglass posts to root canal dentin.

Apical root resorption due to orthodontic treatment detected by cone beam computed tomography.

OBJECTIVE: To determine the frequency of apical root resorption (ARR) due to orthodontic treatment using cone beam computed tomography (CBCT) in a sample of 1256 roots from 30 patients. MATERIALS AND METHODS: All patients had Class I malocclusion with crowding. Of the 30 patients evaluated, 11 were boys and 19 were girls; their mean age was 13 years (11 to 16 years). Orthodontic treatment followed the nonextraction treatment. CBCT images were obtained before and after orthodontic treatment, and ARR was determined using Axial Guided Navigation of CBCT images. RESULTS: All patients had ARR. No statistically significant association was found between resorption frequency, gender, and age. ARR was detected using CBCT in 46% of all roots that underwent orthodontic treatment. CONCLUSIONS: CBCT was effective for detecting in vivo even minimal degrees of ARR due to orthodontic treatment and allowed three-dimensional evaluation of dental roots and visualization of palatine roots of maxillary molars. The highest frequencies and the most significant ARR occurred in incisors and distal roots of first maxillary and mandibular molars.

Caracterização da imagem do canal radicular preenchido com hidróxido de cálcio na tomografia computadorizada de feixe cônico / Characterization of the image of root canal filled with calcium hydroxide in cone beam computed tomography

Objetivo: Caracterizar a imagem do canal radicular preenchido com hidróxido de cálcio na tomografia computadorizada de feixe cônico (TCFC). Metodologia: Vinte e sete canais radiculares foram sanificados e preparados até a lima K-File de no 50, 1 mm aquém do forame apical. A seguir, os dentes foram divididos aleatoriamente em três grupos: grupo 1- canais radiculares preenchidos com pasta de hidróxido de cálcio associado à solução fisiológica (n=9); grupo 2- canais radiculares obturados com Endo-Fill® e cones de guta-percha (n=9); grupo 3- canais radiculares sem preenchimento (n=9). Após o preparo e preenchimento dos canais radiculares, imagens de TCFC foram adquiridas e os espécimes secionados nos planos axial, sagital ou coronal usando brocas Endo Z em alta rotação. As medidas das imagens dos canais nas seções transversais dos espécimes foram obtidas por meio de um paquímetro digital, e nas imagens da TCFC foram obtidas utilizando o programa do fabricante do tomógrafo. As diferenças entre as medidas dos espécimes e das imagens da TCFC foram determinadas em diferentes planos. Resultados: As imagens dos espécimes do grupo contendo pasta de hidróxido de cálcio apresentaram densidades similares às observadas nas dentinas, o que não permitiu a mensuração com vistas a determinar alteração de dimensão. O grupo preenchido com Endo-Fill® e guta-percha apresentou um aumento de 37,40% a 47,40% nas dimensões das imagens radiopacas. Conclusão: Imagens de tomografia computadorizada de feixe cônico em canais radiculares preenchidos com pastas de hidróxido de cálcio apresentaram densidades similares às das dentinas, as quais não demonstraram alterações dimensionais.

Aim: To characterize the image of the root canal filled in with calcium hydroxide in cone beam computed tomography (CBCT). Methodology: Twenty-seven root canals were prepared up to K-file #50, 1 mm below the foramen. After, the teeth were randomly divided into three groups: group 1- root canals filled in with calcium hydroxide paste associated with saline (n=9); group 2- root canals filled with Endo-Fill ® and gutta-percha (n=9); group 3- root canals without filling (n=9). After root canals preparation and filling, CBCT images were acquired and the specimens sectioned in axial, sagittal or coronal plans using Endo Z drills at high speed. Root canals measurements from cross sections of specimens were obtained using a digital caliper, and from CBCT images using the manufacturer?s software. The differences between the sizes of specimens and CBCT images were determined at different plans. Results: Specimens images of the group containing calcium hydroxide paste had densities similar to those ones observed in dentin, which did not allow the measurement in order to determine size change. The group filled in with Endo-Fill ® and gutta-percha showed an increase of 37.40% to 47.40% in the dimensions of radiopaque images. Conclusion: Images of cone beam computed tomography in root canals filled in with calcium hydroxide pastes showed densities similar to those of dentin, which did not determine dimensional changes. Care should be taken that these images are not confused with calcified canals.

Avaliação radiográfica da posição e forma do forame mentual em uma subpopulação Brasileira / Radiographic evaluation of the position and shape of mental foramen in a Brazilian subpopulation

Objetivo: Avaliou-se a posição e a forma do forame mentual em radiografias panorâmicas digitais em uma subpopulação Brasileira. Material e Método: Quinhentas e dezoito radiografias panorâmicas foram consecutivamente selecionadas de um banco de dados secundário de uma clínica radiológica privada e analisadas de acordo com a faixa etária, gênero e simetria. Dois especialistas em radiologia odontológica determinaram a posição horizontal, vertical e o formato de 1036 forames mentuais. Resultados: A frequência do forame mentual com localização entre o longo eixo do primeiro e segundo pré-molares inferiores foi de 55,89%. Não foi observada diferença no posicionamento horizontal em relação ao gênero e a idade. Simetrias foram observadas em 68,91% dos casos. O posicionamento vertical do forame mostrou uma localização comum abaixo dos ápices do primeiro e segundo pré-molar inferior (55,31%). Diferença na relação vertical foi observada apenas em pacientes com idade variando entre 10 a 20 anos. Posições simétricas foram observadas em 84,36% dos casos. Significativa quantidade dos forames mentuais apresentava contorno indefinido/irregular (62,74%), com simetrias em 68,15%. Conclusão: O forame mentual apresentava-se comumente localizado abaixo e entre os primeiros e segundos pré-molares e com formato indefinido/irregular.

Objective: It was evaluated the position and shape of mental foramen on digital panoramic radiographs in a Brazilian subpopulation. Material and Methods: Five hundred and eighteen panoramic radiographs were consecutively selected from a secondary database from a private radiology clinic and analyzed according to age, gender and symmetry. Two specialists in dental radiology determined the horizontal and vertical positions and the format of 1036 mental foramen. Results: The highest frequency of the mental foramen was located between the long axis of the first and second premolars (55.89%). There was no difference in horizontal position in relation to gender and age. Symmetries were observed in 68.91% of the sample. The vertical positioning of the foramen showed a common location below the apex of the first and second lower premolars (55.31%). Difference in vertical relationship was observed only in patients aged 10 to 20 years. Symmetries were observed in 84.36% of cases. A large number of mental foramen had undefined/irregular contours (62.74%), with symmetries in 68.15%. Conclusion: The mental foramen is commonly presented below and between the first and second premolars and with undefined/irregular format.