Limitation of diagnostic value of cone-beam CT in detecting apical root isthmuses

Abstract Isthmuses are reported as common anatomic complexities in teeth often associated with failures in endodontic treatment. They should be considered before starting treatment and a preoperative computed tomography scan (CT) may demonstrate these complexities. Objective To assess the diagnostic value of the highest resolution settings of a cone-beam CT (CBCT) system in identifying and measuring apical isthmuses, using micro-CT as reference. Methodology After micro-CT scanning, 40 humans' lower first molars with isthmuses in the apical-3 mm of mesial roots were scanned by the highest resolution settings of the New Generation i-Cat ® CBCT equipment. Two blinded observers recorded the detection of isthmuses in CBCT scans. The lengths of isthmuses were compared between micro-CT and CBCT to assess the diagnostic value of CBCT. Quantitative data for sensitivity were represented as percentages (95% confidence interval). The Bland-Altman method was used to assess differences between gold standard lengths (micro-CT) and CBCT lengths. Results BCT demonstrated 30 positive findings, representing sensitivity for isthmus identification of 75% (95% CI=0.4114-1.1364). Differences between the lengths in micro-CT (1.99±0.40 mm) and CBCT (1.53±0.41 mm) were significant (p<0.0001). Conclusion The CBCT device used presented limited diagnostic value in the identification and measurement of apical isthmuses in the mesial roots of lower molars. In some cases, the actual anatomy of the apical root canal may not be completely delineated in this type of CBCT system, even using the highest resolution settings.

Influence of NiTi alloy on the root canal shaping capabilities of the ProTaper Universal and ProTaper Gold rotary instrument systems

Abstract Objective This study aimed to evaluate the influence of the NiTi wire in Conventional NiTi (ProTaper Universal PTU) and Controlled Memory NiTi (ProTaper Gold PTG) instrument systems on the quality of root canal preparation. Material and Methods Twelve mandibular molars with separate mesial canals were scanned using a high-definition microcomputed tomography system. The PTU and PTG instruments were used to shape twelve mesial canals each. The canals were scanned after preparation with F2 and F3 instruments of the PTU and PTG systems. The analyzed parameters included the remaining dentin thickness at the apical and cervical levels, root canal volume and untouched canal walls. Data was analyzed for statistical significance by the Friedman and Dunn’s tests. For the comparison of data between groups, the Mann-Whitney test was used. Results In the pre-operative analysis, there were no statistically significant differences between the groups in terms of the area and volume of root canals (P>.05). There was also no statistically significant difference between the systems with respect to root canal volume after use of the F2 and F3 instruments. There was no statistical difference in the dentin thickness at the first apical level between, before and after instrumentation for both systems. At the 3 cervical levels, the PTG maintained centralization of the preparation on the transition between the F2 and F3 instruments, which did not occur with the PTU. Conclusion The Conventional NiTi (PTU) and Controlled Memory NiTi (PTG) instruments displayed comparable capabilities for shaping the straight mesial root canals of mandibular molars, although the PTG was better than the PTU at maintaining the centralization of the shape in the cervical portion.

Evaluation of the internal anatomy and instrumentation techniques with new mechanized instrumentation systems in second mandibular molars with fused roots / Avaliação da anatomia interna, instrumentação e técnicas de retratamento com novos sistemas mecanizados de instrumentação em segundos molares inferiores com raízes fusionadas

O objetivo deste estudo foi analisar por meio da microtomografia computadorizada os aspetos morfológicos e morfométricos da anatomia interna do sistema de canais radiculares com formato em C, e, avaliar a área de superfície, volume e áreas do canal não instrumentadas antes e após a instrumentação dos canais por meio de sistemas alternativos de instrumentação mecanizada, assim como, analisar o efeito de instrumentos manuais com movimento de 90º-oscilatório como instrumentação final. Cinquenta e dois segundos molares inferiores extraídos com canais em forma de C foram escaneados usando micro tomografia computadorizada. As secções transversais do canal radicular foram registradas de acordo com a classificação modificada de Melton. Os parâmetros morfométricos e a configuração tridimensional, foram avaliadas. Depois, 20 dentes com anatomias convergentes e configuração interna C1 foram divididos em dois grupos (n = 10) e instrumentados com Reciproc e SAF respectivamente. Em seguida, uma lima niti #30 do tipo K foi usado em movimento de 90º oscilatório como uma instrumentação final. Os espécimes foram escaneados usando Micro-CT após todos os procedimentos. Os parâmetros morfométricos foram analisados utilizando o programa CTAN. Além disso, a superfície do canal radicular não instrumentada foi calculada por terços. Os resultados indicaram uma distribuição uniforme dentro da amostra. Além disso, a análise da secção transversal revelou predominância das configurações de C4 e C3 a 1 mm a partir do ápice e as configurações C1 e C2 no terço cervical. De acordo com os parâmetros morfométricos, o tipo C1 e o canal distal do C2 apresentaram os menores valores de circularidade e valores mais elevados para a área, diâmetro maior e menor no terço apical. Todos os valores relativos a analise de instrumentação foram comparados entre os grupos utilizando o teste de Mann- Whitney e a comparação intra-grupos usando o teste de Wilcoxon. A instrumentação com Reciproc aumentou significativamente o volume do canal em comparação com SAF. Além disso, os volumes dos canais foram significativamente aumentados após a instrumentação de 90º-oscilatória (P <0,05). Depois de todos os protocolos de instrumentação, o aumento de área de superfície só revelou diferenças significativas na comparação intra-grupos (P <0,05). A instrumentação com Reciproc e SAF deixou 28% e 34%, de áreas não instrumentadas respectivamente, sem diferença estatística (P> 0,05). Já a instrumentação oscilatória final reduziu as superfícies do canal radicular não instrumentadas de 28% para 9% (Reciproc) e de 34% para 15% (SAF; P <0,05). Os molares inferiores com canais radiculares em forma de C apresentaram distribuições semelhantes de canais simétricos, assimétricos e convergentes. A configuração C1 e o aspecto distal da configuração C2 apresentaram os maiores valores de área de e diâmetros apicais. Além disso, o uso final da instrumentação com 90º oscilatório usando instrumentos manuais de NiTi diminuiu significativamente as paredes do canal não instrumentadas que permaneceram após a instrumentação com Reciproc e SAF. Finalmente, a combinação de dois sistemas ou técnicas de instrumentação provaram ser eficazes na obtenção de melhores resultados na instrumentação de segundos molares inferiores em forma de C.(AU)

The present study evaluated the morphometric aspects of the internal anatomy of the root canal and the effect of 90º-oscillatory instrumentation with hand files on volume, surface area and uninstrumented surface after shaping procedures with Self adjusting file and Reciproc in mandibular second molars with C-shaped canals. 52 extracted mandibular second molars with C-shaped canals were scanned with a micro-computed tomography scanner. The root canal cross-sections were recorded according to the modified Melton classification. Morphometric parameters and the tridimensional configuration, were evaluated. Afterwards, 20 teeth with merging type canals and C1 internal configuration were divided in two groups (n = 10) and instrumented with Reciproc and SAF instruments respectively. Then, a size 30 Niti hand K-file used in 90º-oscillatory was used as a final instrumentation. The specimens were scanned using Micro-CT after all procedures. Morphometric parameters were analyzed using CTAn software. Also, the uninstrumented root canal surface was calculated for each canal third. The results indicated an even distribution within the sample. Also, the cross-sectional configuration analysis revealed predominance of the C4 and C3 configurations at 1 mm from the apex and the C1 and C2 configurations in the cervical third. According to the morphometric parameters, the C1 and the distal aspect of the C2 exhibited the lowest roundness values and higher values for the area, major diameter and aspect ratio in the apical third. All values were compared between groups using the Mann­Whitney test and within groups using the Wilcoxon's signed-rank test. The significance level was set at 5%. Instrumentation with Reciproc significantly increased canal volume compared to SAF and the canal volumes were significantly increased after 90º-oscillatory instrumentation (P < 0.05). After all instrumentation protocols the surface area increase only revealed significant differences in the within groups comparison (P < 0.05). Reciproc and SAF instrumentation yielded a uninstrumented root canal surface of 28% and 34%, respectively, without differences (P > 0.05). Final oscillatory instrumentation reduced the uninstrumented root canal surface from 28% to 9% (Reciproc) and from 34% to 15% (SAF; P < 0.05). The apical and middle thirds exhibited higher uninstrumented root canal surfaces after the first instrumentation that was significantly reduced after oscillatory instrumentation (P < 0.05). Mandibular molars with C-shaped root canals exhibited similar distributions of symmetrical, asymmetrical and merging-type canals. The C1 configuration and the distal aspect of the C2 configuration exhibited the highest area values and large apical diameters. Furthermore, the final use of 90º-oscillatory instrumentation using NiTi hand files significantly decreased the uninstrumented canal walls that remained after Reciproc and SAF instrumentation. Finally, the combination of two instrumentation systems/techniques proved to be effective in achieving better instrumentation results in C-shaped mandibular second molars.(AU)

Influência do tipo de instrumento empregado para agitação ultrassônica na capacidade de remoção da smear layer / Influence of the type of instrument used in passive ultrasonic irrigation on the smear layer removal capacity

Introdução: o objetivo do presente estudo foi avaliar a capacidade de remoção da smear layer de limas manuais de aço inoxidável e de NiTi e de fio ortodôntico de NiTi, ativados pelo ultrassom. Métodos: 50 canais de raízes palatinas de molares superiores foram dilatados, no terço cervical, com a broca Laxxess 35 e, no terço apical, com o sistema ProTaper, até o instrumento F4, no comprimento real de trabalho. Os canais foram irrigados com hipoclorito de sódio a 1% e divididos em cinco grupos: GI = EDTA + ultrassom por 1 minuto com lima 15 do tipo K de aço inoxidável; GII = EDTA + ultrassom por 1 minuto com lima tipo K 15 de NiTi; GIII = EDTA + ultrassom por 1 minuto com fio ortodôntico #25 x 11 de NiTi; GIV = EDTA por 3 minutos sem agitação com ultrassom; GV = sem EDTA nem ultrassom. Posteriormente, cada raiz foi seccionada longitudinalmente e uma hemissecção foi metalizada e analisada em microscópio eletrônico de varredura, sendo feitas imagens de cada uma delas, nos três terços, estipulando-se os seguintes escores: 0 = nenhuma camada de detritos dentinários, com túbulos dentinários limpos e abertos; 1 = camada moderada de detritos dentinários; 2 = camada espessa de detritos dentinários, cobrindo a superfície dos túbulos dentinários. Os dados foram comparados estatisticamente. Resultados: após observar a smear layer nos três terços, verificou-se que todos os grupos que usaram o EDTA se diferenciaram estatisticamente (p < 0,05) do grupo sem EDTA. Não houve, porém, diferenças significativas entre os grupos com agitação ultrassônica e o grupo de EDTA sem ultrassom. Não houve diferenças significativas (p < 0,05) entre os três instrumentos empregados. Conclusão: o uso do EDTA favoreceu a remoção da smear layer. A ativação ultrassônica do EDTA por 1 minuto, independentemente do instrumento empregado, favoreceu a obtenção de paredes mais limpas.

A new improved protocol for in vitro intratubular dentinal bacterial contamination for antimicrobial endodontic tests: standardization and validation by confocal laser scanning microscopy

Objectives To compare three methods of intratubular contamination that simulate endodontic infections using confocal laser scanning microscopy (CLSM). Material and Methods Two pre-existing models of dentinal contamination were used to induce intratubular infection (groups A and B). These methods were modified in an attempt to improve the model (group C). Among the modifications it may be included: specimen contamination for five days, ultrasonic bath with BHI broth after specimen sterilization, use of E. faecalisduring the exponential growth phase, greater concentration of inoculum, and two cycles of centrifugation on alternate days with changes of culture media. All specimens were longitudinally sectioned and stained with of LIVE/DEAD® for 20 min. Specimens were assessed using CLSM, which provided images of the depth of viable bacterial proliferation inside the dentinal tubules. Additionally, three examiners used scores to classify the CLSM images according to the following parameters: homogeneity, density, and depth of the bacterial contamination inside the dentinal tubules. Kruskal-Wallis and Dunn’s tests were used to evaluate the live and dead cells rates, and the scores obtained. Results The contamination scores revealed higher contamination levels in group C when compared with groups A and B (p<0.05). No differences were observed between group A and B (p>0.05). The volume of live cells in group C was higher than in groups A and B (p<0.05). Conclusion The new protocol for intratubular infection resulted in high and uniform patterns of bacterial contamination and higher cell viability in all specimens when compared with the current methods.

Prevalencia de alteraciones en el complejo estilohiodeo en radiografías panorámicas digitales / Prevalence of alterations of the stylohyoid complex in digital panoramic radiographs

Introducción: alteraciones de este aparato estilohioideo son frecuentes y se manifiestan por el alargamiento del proceso estiloides y también por la osificación del ligamento estilohioideo. Los cambios pueden ser asintomáticos o pueden desencadenar una serie de síntomas como el dolor en cabeza. Objetivo: determinar la prevalencia del alargamiento del proceso estiloide y de la osificación del ligamento estilohioideo en radiografías panorámicas, atendiendo a la distribución según edad, sexo y lado afectado. Métodos: se tomaron 300 radiografías panorámicas digitales de los archivos de un Servicio de Radiología Dental. Fueron seleccionadas al azar entre las realizadas en 2012, y evaluadas por un único examinador. Fueron consideradas las radiografías en las cuales el proceso estiloide del hueso temporal superaba en más de 1 cm el borde más inferior del cartílago del lóbulo de la oreja y aquellas en la que el ligamento estilohioideo aparecía radiopaco. Resultados: en este estudio, se encontraron 108 radiografías (36 por ciento) con estas condiciones. Hubo una mayor prevalencia de alargamiento del proceso estiloide y/o la osificación del ligamento estilohioideo en mujeres (63 por ciento); se presentó bilateralmente en 72 por ciento de los casos, con mayor prevalencia en el rango etario de 61 a 70 años. Conclusión: la prevalencia de alteraciones en el complejo estilohioideo en las radiografías analizadas fue de 36 por ciento, la mayoría con presentación bilateral; predominó en mujeres del grupo etario referido(AU)

Introduction: alterations of the stylohyoid chain are common, taking the shape of styloid process elongation and stylohyoid ligament ossification. Changes may either be asymptomatic or trigger a number of symptoms such as headache. Objective: determine the prevalence of styloid process elongation and stylohyoid ligament ossification in panoramic radiographs based on distribution by age, sex and affected side. Methods: examination was conducted of 300 digital panoramic radiographs from the registries of a dental radiology service. Radiographs were randomly selected from among those performed in 2012, and evaluated by a single researcher. The radiographs considered were those in which the temporal styloid process exceeded in more than 1 cm the lowermost edge of the earlobe cartilage and those in which the stylohyoid ligament was radiopaque. Results: the study found 108 radiographs (36 percent) meeting these requirements. There was a higher prevalence of styloid process elongation and/or stylohyoid ligament ossification among women (63 percent), whereas the condition was bilateral in 72 percent of the cases, with a predominance of the 61-70 age group. Conclusion: prevalence of alterations of the stylohyoid complex in the radiographs analyzed was 36 percent. Most alterations were bilateral. There was a predominance of women from the above-mentioned age group(AU)

Revascularização pulpar: considerações técnicas e implicações clinícas / Pulp revascularization: technical considerations and clinical implications

O tratamento endodôntico de dentes portadores de necrose pulpar e rizogênese incompleta têm sido tratados, recentemente, por meio da revascularização pulpar. Essa promissora alternativa de tratamento promove tanto o fechamento apical quanto o término do desenvolvimento radicular. Atualmente vários protocolos têm sido propostos, entretanto pouco se sabe sobre o sucesso por meio da instrumentação mecânica e do uso de medicações a base de hidróxido de cálcio ou pasta tri-antibiótica nos casos com indicação de revascularização pulpar. Objetivo : O objetivo deste estudo foi realizar uma revisão da literatura abordando os protocolos de revascularização e suas implicações clínicas para o tratamento de dentes portadores de necrose pulpar e ápices incompletos. Resultados e discussão: As causas que normalmente interrompem a formação radicular são os traumatismos dentários e cáries dentárias, que podem causar a necrose pulpar. Sendo assim, os dentes que apresentam rizogênese incompleta e necrose pulpar geralmente eram tratados pelo método de apicificação ou mesmo a confecção de um plug apical de MTA, a fim de conseguir a formação de uma barreira apical. Porém, através desse método, as raízes continuam com as paredes dentinárias finas e fragilizadas. Conclusão: Com base nessa revisão, pode-se concluir que a revascularização pulpar é uma alternativa como tratamento para dentes com rizogênese incompleta portadores de necrose pulpar, porém, não há um protocolo estabelecido e considerado ideal...

Endodontic treatment of immature teeth with necrotic pulp and incomplete root formation has been recently treated with pulp revascularization. It is a promising alternative treatment to promote apical closure and root development. To date, a variety of revascularization protocols have been described, however little is known about the success of combining mechanical instrumentation and intracanal medication such as calcium hydroxide or triantibiotic paste. Thus, the aim of this study is to present a review of literature of pulp revascularization protocols and its clinical implications for treatment of teeth with pulp necrosis and incomplete apex. The causes that usually interrupt the root formation are dental traumatisms and caries, which can lead to pulp necrosis. Therefore, the immature permanent teeth and pulp necrosis were usually treated by apexification or the confection of an apical MTA plug, in order to accomplish the formation of an apical barrier. However, by this method, the roots canal walls remain thin and fragile. It may be concluded that the pulp revascularization treatment is an alternative approach for immature permanent teeth with pulp necrosis. However, there is not a standardized protocol that is considered ideal in these cases...