Endodontic treatment of a mandibular hypertaurodontic second molar / Tratamento endodôntico de segundo molar inferior com hipertaurodontia

Taurodontism is the consequence of a developmental disorder in which the invagination of Hertwig's epithelial root sheath doesn't occur at a proper level. As a result, the pulp body and the chamber of a multi-root tooth, usually permanent molar teeth, are enlarged by the apical displacement of the pulp floor. Despite its clinically normal appearance, the morphological variation of this tooth can be diagnosed by a routine radiographic exam that shows enlarged apico-occlusal pulp chamber and short roots. Due to these anatomical variations, endodontic treatment of a taurodontic element is a clinical challenge given the complexity of localization and instrumentation of the root canal system. According to the degree of displacement of the pulp floor, taurodontism can be classified as: hypotaurodontism, mesotaurodontism and hypertaurodontism. This study objective is to report a clinical case of a patient who was submitted to endodontic treatment of the second inferior molar affected by hypertaurodontism.

A taurodontia é consequência de um distúrbio de desenvolvimento em que a bainha epitelial de Hertwig não invagina corretamente em um nível normal, repercutindo em um aumento do corpo e da câmara pulpar de um dente multiradicular, predominantemente molares permanentes, pelo deslocamento do assoalho pulpar no sentido apical. Apesar de clinicamente aparentar-se como um dente normal, esta variação morfológica pode ser diagnosticada por exame radiográfico de rotina evidenciando câmara pulpar aumentadas em tamanho no sentido ápico-oclusal e raízes curtas. Devido a estas alterações anatômicas, o tratamento endodôntico de um elemento com taurodontia se torna um desafio clínico, já que é necessário um cuidado especial na localização e manejo do sistema de canais radiculares. De acordo com o grau de deslocamento apical do assoalho pulpar, a taurodontia pode ser classificada em: hipotaurodontia, mesotaurodontia e hipertaurodontia. O objetivo deste trabalho é relatar o caso clínico de um paciente que necessitou de tratamento endodôntico em um segundo molar inferior com hipertaurodontia.

Effectiveness of rotatory and reciprocating movements in root canal filling material removal

The purpose of this study was to compare the efficacy of reciprocating and rotary techniques for removing gutta-percha and sealer from root canals. Forty straight and oval single-rooted premolars were prepared up to size 30, filled with gutta-percha and sealer, and then randomly allocated to two experimental retreatment groups: ProTaper Retreatment System (PTRS) and WaveOne System (WS). Procedural errors, time of retreatment and apically extruded material were recorded for all the roots. The roots were radiographed after retreatment. The percentage of residual material was calculated using image analysis software. The data were analyzed by Kolmogorov-Smirnov and t tests, with a significance level set at 5%. No system completely removed the root filling material from the root canal. No significant differences were observed between the systems, in terms of residual filling material in any tested third (p > 0.05). WS was faster in removing filling material than PTRS (p< 0.05). Extrusion was observed in 4 cases in PTRS and in 5 cases in WS. No procedural errors were observed in either group. It can be concluded that although no differences were observed in the efficacy of PTRS and WS for removing root filling material, WS was faster than PTRS.

A multiparametric assay to compare the cytotoxicity of different storage media for avulsed teeth

Aim: To evaluate the cytotoxicity of several storage media (coconut water, whole milk, isotonicsolution, Hank´s Balanced Salt Solution and tap water) using a multiparametric cytotoxicity analysisemploying 3T3 cells. Methods: Plates containing confluent 3T3 fibroblasts were exposed to thevarious media for 24h, at 37°C with 5% CO2, and cell viability was evaluated by a multiparametricassay assessing sequentially, on the same cells, mitochondrial activity (XTT), membrane integrity(neutral red test), and total cell density (crystal violet dye exclusion test). Results from each testwere compared by one-way analysis of variance (ANOVA). Results: Statistical analysis showedthat whole milk and HBSS were the most effective media in maintaining cell viability at all testedtimes (p<0.05). Isotonic and tap water showed the highest cytotoxicity effects. Conclusions: Thisstudy shows that whole milk and HBSS are more efficient in maintaining the viability of 3T3fibroblasts as demonstrated by three different cell viability tests.

Preliminary investigation to achieve patency of MB2 canal in maxillary molars

Aim: To establish a preliminary investigation about the possibility to achieve patency of second mesiobuccal canal (MB2) in mesiobuccal roots of maxillary molars. Methods: Three hundred and five first maxillary molars were examined with direct vision and with magnification. The root canal configurations were classified according to the possibility to achieve patency in MB2 canals. Clearing technique was also performed to illustrate root canal anatomy and verify the presence of extra canals not identified with magnification. Results: The prevalence of MB2 canals detected only with direct vision was 53.4% and the use of the surgical operating microscope increased rate detection to 90.7%. The clearing technique revealed the presence of MB2 canal in 12 more teeth (94.7%). In 49.1% of the localized MB2 canals, it was not possible to achieve patency. Conclusions: The findings of the presented study revealed that it was only possible to achieve patency in 50.9% of the MB2 canals, showing that achieve patency in the MB2 canal is much more challenging than locating them.

Clinical reproducibility of a low cost electronic apex locator

Aim: To evaluate the clinical reproducibility of three electronic apex locators (EALs), Joypex 5,RomiApex A-15 and Novapex. Methods: Twenty-five patients requiring endodontic treatmentwere selected. Sixty root canals were measured by the three EALs to determine their respectiveworking length, which was defined as a zero reading on the EAL. A new K-file of the same sizewas used for each measurement. The file length was fixed with a rubber stop and measured witha caliper to an accuracy of 0.1 mm. Data were analyzed statistically using paired t-tests with theBonferroni correction and Bland-Altman plot to determine the reproducibility of clinical dataamong the EALs. Significance level was set at 5%. Results: Mean and standard deviationvalues measured by the three EALs showed no statistically significant differences. Identicalreadings by all three EALs were found in 38% of root canals. Fifty percent differed by less than± 1.0 mm and only 1.3% exceeded a difference of 2.0 mm. Conclusions: The clinicalreproducibility of the three devices was confirmed with no significant differences among them,indicating that they are effective for clinical use.

Eficácia de localizadores apicais na identificação de perfurações de diferentes diâmetros / Efficacy of apex locators in the identification of different diameters perforations

Introdução: O objetivo deste estudo in vitro foi avaliar a precisão dos localizadores apicais eletrônicos (LAEs) Novapex® e Root ZX II® na detecção de perfurações radiculares simuladas. Metodologia: Após a remoção da porção coronária de 35 dentes, perfurações artificiais foram realizadas no terço médio com brocas de diferentes diâmetros (01, 04, 08). Os dentes foram então divididos em quatro grupos: três grupos experimentais, com dez dentes, e o grupo de controle, com cinco dentes. Todos foram embebidos em solução salina 0,9% e as determinações eletrônicas da localização das perfurações foram realizadas com os LAEs. Uma lima 10 tipo K foi inserida nos canais até que os LAEs indicassem que tivesse atingido a marca de 0. Logo após, os cursores foram ajustados em uma referência externa. Três medidas foram tomadas para cada dente e obtida uma média. Resultados: Os resultados mostram que o maior diâmetro da perfuração aumentou a sensibilidade LAEs na localização das perfurações. Para comparação de medidas reais com as medidas fornecidas pelo LAE, nos casos em que os LAEs foram capazes de localizar a perfuração, o teste t de student foi utilizado (p < 0,05), não apresentando diferença estatisticamente significante en-tre as diferentes perfurações e os diferentes LAEs. Con-clusão: Os LAEs testados foram precisos e confiáveis na determinação de perfurações de raiz, sendo capazes de auxiliar no diagnóstico clínico desta patologia.

Avaliação in vitro da eficiência de um localizador apical eletrônico em dentes com reabsorções radiculares simuladas

Objetivo: avaliar in vitro a eficiência do localizador apical eletrônico Novapex (Fórum Technologies, Israel)em determinar o comprimento de trabalho, quando utilizado em situações clínicas diferentes, como em dentes com reabsorções externas e internas simuladas.Métodos: para isso, foram usados 30 dentes humanos unirradiculares extraídos (caninos inferiores), com ápices completamente formados e com o mesmo padrão de volume na região apical, utilizando-se apenas sua porção radicular. Inicialmente, cada dente teve seu comprimento determinado visualmente, com uma lima tipo K #10 até o aparecimento dessa no forame apical,de onde se recuou 1mm, definindo a medida do comprimento de trabalho real. A medida foi tomada novamente com a utilização do aparelho localizador apical eletrônico Novapex e considerada como comprimento eletrônico inicial. Logo após, foram preparados os desgastes para simular as reabsorções externas e internas.As medidas foram tomadas novamente com o aparelho,e as mesmas foram tabuladas e analisadas. Resultados:o Novapex foi altamente preciso quando consideradas variações de 1mm aquém da medida predeterminada.Conclusão: através desse estudo, constatou-se que o localizador apical Novapex foi eficaz, mostrando-se um método confiável, e nenhuma interferência significativa na sua leitura foi detectada quando da presença de reabsorções externas e internas simuladas