Estudo in vitro da morfologia interna de pré-molares superiores e inferiores por meio de quatro métodos / In vitro study of maxillary and mandibular premolars internal morphology by means of four methods

O objetivo desse trabalho foi avaliar, in vitro, por meio de quatro critérios (radiográfico, macroscópico, microscópico e cortes seriados), a quantidade e configuração dos canais em pré-molares superiores e inferiores. Trata-se de um estudo transversal observacional e descritivo, no qual foram selecionados 100 pré-molares, tendo como critério de exclusão aqueles bastante destruídos por cárie, com tratamentos endodônticos prévios, rizogênese incompleta, reabsorções e/ou fraturas. Os dentes foram divididos em quatro grupos (n = 25): G1 = primeiros pré-molares superiores; G2 = segundos pré-molares superiores; G3 = primeiros pré-molares inferiores; e G4 = segundos pré-molares inferiores. Os resultados obtidos mostraram que 100% do G1 apresentaram dois canais radiculares na avaliação macroscópica, que se fundiam em várias alturas da raiz, possuindo maior prevalência de configuração oval (68%). O G2 revelou 60% de canais radiculares únicos e formato oval (84%). Os resultados obtidos no G3 foram raiz única e canal único (100%) e incidência de configuração oval (72%). Por fim, o G4 apresentou maior prevalência de um canal radicular em uma única raiz (92%) e prevalência de configuração oval (64%). Portanto, por meio da metodologia utilizada nesse estudo, houve prevalência de canais radiculares ovais em todos os grupos, predominando nos primeiros pré-molares superiores a presença de dois canais radiculares, enquanto nos demais grupos prevaleceu apenas um canal radicular.

Avaliação da descontaminação de cones de guta-percha usando diferentes métodos de desinfecção / Evaluation of gutta-percha points decontamination through different disinfection methods

A suscetibilidade ao crescimento bacteriano em cones de guta-percha (GP) e a forma de descontaminação desses cones usando quatro diferentes substâncias químicas foram avaliadas. Seis cones de GP foram selecionados de um ambiente clínico e levados com pinça estéril para um meio de cultura de Brain Heart Infusion (BHI), para avaliação de crescimento bacteriano. Outros doze cones foram divididos em quatro grupos experimentais de três cones, sendo: Grupo 1, hipoclorito de sódio a 2,5%; Grupo 2, álcool a 70%; Grupo 3, clorexidina gel a 2%; e Grupo 4, clorexidina líquida a 0,12%, onde cada cone ficou submerso na substância por um minuto, foi seco por meio de esfregaço com gaze estéril e inserido em meio de cultura BHI, para se avaliar a presença ou não de contaminação. Os resultados encontrados mostraram que os cones de guta-percha não apresentavam contaminação, independentemente de serem submetidos ou não a um processo de descontaminação. Dessa forma, conclui-se que não há necessidade de descontaminação dos cones de guta-percha, contanto que seja respeitada a cadeia asséptica do tratamento endodôntico.

Cyclic fatigue resistance of different continuous rotation and reciprocating endodontic systems.

Objective: The objective of this study is to compare the cyclic fatigue resistance of nine types of endodontic instruments of nickel–titanium. Materials and Methods: Five files of 25 mm of length of each group: Reciproc (RC) R25; WaveOne (WO) Primary; Unicone (UC) L25 25/0.06; K3XF 25/0.06; ProTaper Universal F2 (PTF2); ProTaper Next X2 (PTX2); Mtwo 25/0.06; BioRaCe 25/0.06; One Shape L25 25/0.06 were subjected to a cyclic fatigue resistance test on a mechanical apparatus. The mean fracture time was analyzed statistically by one-way analysis of variance and Tukey’s honest significant difference post hoc test, with significance set at P < 0.05. Conclusion: It was observed that the groups PTX2, RC, R25, UC L25 25/0.06, and WO Primary presented greater cyclic fracture resistance than the other groups (P < 0.001).

Accuracy evaluation of three electronic apex locators in teeth with immature apices

Introduction and Objective: The aim of this randomized controlled study was to evaluate the accuracy of Root ZX, iPex and YS-RZ-A apex locators in tooth with incomplete apices. Material and methods: Thirty human mandibular pre-molars without dental caries, fracture and with 1-3mm apical diameter and ¾ of root development stage were used. After coronal access, tooth length was determined with the visualization of a K-file, compatible with the root canal diameter, at the apex. To determine the root canal length using electronic methods, the teeth were included in alginate. The 30 teeth were measured with the three apex locators until achieving the apex foramen. During the measurement, the canals were inundated with 1% sodium hypochlorite. Statistical analysis was performed using Qui-square test (p < 0.05). Results: The Root ZX apex locator showed the higher accuracy (53.3%), with statistical difference in relation to iPex apex locator (33.3%) and YS-RZ-A apex locator (26.7%) (p < 0.05). Regarding the security limit of ±1 mm, the Root ZX apex locator did not show statistical difference in comparison with iPex apex locator (p > 0.05), but both were statistically different in relation to YS-RZ-A apex locator (p < 0.05). Conclusion: The results showed that all the studied apex locators were efficient in determining the root canal length in tooth with incomplete apex, considering the tolerance of ±1 mm. The Root ZX apex locator showed the highest accuracy with 100% of agreement.

Two root canals in maxillary central incisor

Introduction and objective: The success of endodontic treatment requires the knowledge of tooth morphology and its variations. Case report: This clinical article reports an unusual root canal configuration that was detected in a maxillary central incisor with two root canals, demonstrated by radiographic and computerized tomography exams. Conclusion: Knowledge of endodontic anatomy as well as the obtainment of both preoperative radiographs and tomography is important to detect abnormal tooth morphology.

Evaluation of the dentin remaining after flaring using Gates Glidden drills and Protaper rotary files

INTRODUCTION: The application of rotary instruments for root canal preparation requires a safe, not harming procedure to the root structure remaining. OBJECTIVES: The purpose of this study was to analyze the root thickness in 28 mesial canals of lower permanent first molars before and after flaring using two rotary instruments: Gates-Glidden drills and ProTaper rotary files. MATERIAL AND METHODS: Teeth were embedded into a muffle system. Samples were obtained by cutting 2mm below the furcation. The images were captured by a digital video system (8X and 12X magnification). For image analysis and processing, Pro-Image Plus 4.1 software was used. Each image captured by the computer was gauged, eliminating any possible distortion. Gates-Glidden drills were used in decreasing order of size (GG#4, GG#3, GG#2). ProTaper was used according to the manufacturer's recommendations, with hand-piece powered by an electric motor with low torque. 5.25 percent sodium hypochlorite was utilized as irrigant. RESULTS: The average thickness between the canal and furcation before and after use of rotary instruments were: 0.857 mm and 0.561 mm for Gates-Glidden drills, and 0.858 mm and 0.486 mm for ProTaper, respectively. No statistical differences were found in the root thickness of specimens shaped with ProTaper rotary files and Gates Glidden drills. CONCLUSION: The use of Gates-Glidden drills is as safe as ProTaper rotary files with respect to danger of perforation on the distal side of the mesial roots of lower molars.

Análise da espessura da linha de cimento após o uso de diferentes técnicas de obturação de canais radiculares / Evaluation of the film thickness of a root canal sealer following different filling techniques

Introdução: O objetivo deste estudo foi realizar uma análise quantitativa da espessura da linha de cimento endodôntico formada após o uso de três diferentes técnicas de obturação. Materiais e método: Foram utilizados sessenta pré-molares inferiores. Após os procedimentos de limpeza e modelagem, os dentes foram distribuídos aleatoriamente em três grupos, de acordo com a técnica de obturação a ser empregada: Grupo I - Compressão hidráulica; Grupo II - Condensação lateral; Grupo III - Híbrida de Tagger. Foi utilizado no experimento um cimento a base de óxido de zinco eugenol. Os espécimes foram analisados em quatro cortes: 12 mm, 9 mm, 6 mm e 3 mm aquém do ápice radicular. As imagens dos cortes transversais foram capturadas e a espessura de cimento foi mensurada utilizando-se o programa Image Tool 3.0. A análise estatística foi executada utilizando-se o teste de Wilcoxon (SPSS 12.0). Resultados: A técnica de Tagger foi superior às demais, seguida pela compressão hidráulica e condensação lateral, com os resultados mostrarando-se estatisticamente diferentes entre todos os grupos (p = 0,0109). Conclusões: Em geral, as menores espessuras de cimento foram obtidas para o Grupo III, sendo piores os resultados obtidos para o grupo da condensação lateral.

Ex vivo evaluation of coronal and apical microbial leakage of root canal - Filled with gutta-percha or Resilon/Epiphany root canal filling material.

Objective: This ex vivo study compared coronal and apical microleakage of root canals filled with Resilon/Epiphany (RE) or gutta-percha/Grossman sealer (GP), using either lateral condensation (LC) or System B (SB) technique. Materials and Methods: Specimens in eight experimental groups were obturated using the following materials and techniques: Groups 1 and 3 - GP and LC; groups 2 and 4 - GP and SB; groups 5 and 7 - RE and LC; groups 6 and 8 - RE and SB. Apical and coronal leakages were tested using bacterial methods. For coronal analysis, the number of days required for complete contamination of the root canals was recorded according to observation of the brain heart infusion broth turbidity for 15 weeks. For apical analysis, the teeth were cleaved and the leakage was measured at 30 days. Data were collected for each sample and analyzed statistically with the Chi-square and ANOVA tests. Results: Leakage was found in all groups. The difference between filling materials, obturation techniques, and median time of leakage was not statistically significant for coronal ( P=0.847) and apical ( P=0.5789) leakages. Conclusion: There were no differences between the different filling materials (gutta-percha/Grossman sealer and Resilon/Epiphany) and obturation techniques (lateral condensation and system B technique) in coronal or apical leakages.

Three root canals in the maxillary second premolar.

In this study, we report an endodontic treatment of the maxillary second premolar with three root canals and distinct foramens. The possibility of three root canals in this tooth is quite small; however, it must be taken into account in clinical and radiographic evaluation during endodontic treatment. Many times, their presence is noticed only after canal treatment due to continuing post-operative discomfort.