Estudo ex vivo da elevação do pH em superfície radicular externa após agitação ultrassônica de diferentes pastas de hidróxido de cálcio / Assessment of pH increase in the external root surface after ultrasonic agitation of different calcium hydroxide pastes: Ex vivo study

Objetivo: O presente estudo teve por objetivo avaliar, ex vivo, a capacidade de elevação do pH da superfície radicular externa de diferentes pastas de hidróxido de cálcio (HC) utilizadas como medicação intracanal, além da influência da ativação ultrassônica (AUS) durante aplicação no interior do canal radicular. Métodos: Foram utilizados 100 incisivos humanos superiores unirradiculares, que tiveram os canais radiculares modelados e divididos aleatoriamente em seis grupos experimentais (n=15), de acordo com a pasta de HC, tendo como variáveis as medicações utilizadas e a ativação da pasta com AUS no momento da aplicação, além de um grupo controle (n=10): Pasta Calen; HC+clorexidina 2% gel (CX2%); e HC + água destilada. Os dentes foram mantidos imersos em água deionizada e as medidas do pH, verificadas nos períodos de 7, 14, 21 e 28 dias, com auxílio de pHmetro. Resultados: De acordo com os dados obtidos, verificou-se elevação do pH nos períodos de 7 e 14 dias em todos os grupos. Apenas os grupos em que foi utilizada a associação do HC com CX2% apresentou evolução com aumento significativo do pH ao longo dos períodos analisados (p<0,05). A ativação das pastas com AUS proporcionou incremento significativo dos valores de pH (p<0,05). Conclusão: De acordo com a metodologia empregada, pode-se concluir que todas as pastas utilizadas promovem elevação do pH no tecido dentinário, e a ativação das pastas com AUS influencia significativamente na elevação do pH no tecido dentinário (AU).

Objective: The aim of the present study was to evaluate, ex-vivo, the pH elevation capacity on the external root surface of different calcium hydroxide (HC) pastes, utilized as intracanal medication, it was also evaluated the influence of the ultrasonic activation at the application within the root canal. Methods: 100 human single root superior incisors were used, which had their root canals shaped and randomly divided into 6 experimental groups (n=15) according to the following HC pastes: Calen; HC + Chlorhex- idine 2% gel (CX2%); HC + distilled water, utilizing the medications and the ultrasonic activation of the paste at the time of the application as variables and 1 control group (n=10). The teeth were kept immersed in deionized water and the pH parameters were verified in 7, 14, 21 and 28 days with a pH measurement machine. Results: According to the data obtained, pH was elevated in the first week in all groups. Only the groups which the association of HC with CX2% was made, did show a significant increase in the pH level over the analyzed periods (p < 0,05). The activation of the pastes with US provided a significant increase in pH values (p < 0,05). Conclusion: According to the methodology used, we can conclude that all the HC pastes used, promote pH elevation in dentin tissue. And the acti- vation of the pastes with US significantly influences the pH increase in dentin tissue

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.

Evaluation of apically extruded debris during endodontic retreatment

Introduction: A growing interest to preserve teeth into the mouth by patients resulted in the increasing number of endodontic retreatments, and when these happen, many different types of irritants are extruded through the foramen. Objective: This study analyzed in vitro the amount of debris extruded through the foramen using four instrumentation techniques during endodontic retreatment. Material and methods: Forty mesial-buccal roots of first molars were selected, instrumented with anatomical diameter up to size #30 ISO file and then obturated with gutta-percha and grossman sealer by lateral condensation. After, they were separated and randomly allocated into four groups with 10 teeth each for the endodontic retreatment procedure: G1 - conventional technique + solvent, G2 - conventional technique without solvent, G3 - ProTaper retreatment + solvent, G4 - ProTaper retreatment without solvent. In all groups, gutta-percha in the coronal portion was removed by using size 1-3 Gates Glidden drills. All teeth were irrigated with distilled water. The debris extruded through the foramen were collected and weighed by an analytical balance. Results: Group 4 had the lowest average for material extrusion through the foramen followed by groups 2, 3 and 1. When Tukey test for statistical analysis was applied, no significant difference among groups were found (p = 0.5664). Conclusion: We conclude that all instrumentation techniques used in this study produced debris which goes beyond the foramen.

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.

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.

Análise da capacidade de preenchimento de canais radiculares com guta-percha promovida por três diferentes técnicas de obturação de canais radiculares / Analysis of gutta-percha's root canal filling capacity through three different obturation techniques

Introdução e objetivo: O objetivo deste estudo foi determinar a deste estudo foi determinar a capacidade de preenchimento de canais radiculares com guta-percha por meio de três diferentes técnicas de obturação endodôntica. Material e métodos: Utilizaram-se 60 dentes unirradiculados, os quais foram limpos, modelados e divididos aleatoriamente em três grupos. Recorreuse a três técnicas distintas de obturação para cada grupo de estudo: grupo I ­ condensação lateral; grupo II ­ compressão hidráulica; grupo III ­ híbrida de Tagger. Todos os procedimentos foram executados por dois operadores calibrados em momento anterior. Após os procedimentos de obturação, seccionaram-se os espécimes transversalmente em quatro medidas a partir do ápice radicular (3 mm, 6 mm, 9 mm e 12 mm), com auxílio de disco de diamante montado em IsoMet®, sob intensa refrigeração e baixa rotação. Esses cortes foram incluídos em resina plástica e lixados, e as imagens dos canais radiculares capturadas e analisadas com auxílio do programa Image Tool 3.0. Mensuraram-se as áreas dos canais radiculares e de toda a massa de guta-percha presente no interior do canal radicular, a fim de obter a porcentagem de preenchimento do canal radicular com material guta-percha para cada corte. Resultados: Os resultados foram tabulados e avaliados por intermédio do programa GMC 10.0 (Kruskal-Wallis). A análise dos resultados evidenciou que a técnica híbrida de Tagger (95,1%) foi superior às demais na capacidade de preenchimento do canal radicular com guta-percha, seguida das técnicas da compressão hidráulica (89,1%) e da condensação lateral (70,6%). Os resultados mostraram-se diferentes estatisticamente entre as técnicas empregadas (p < 0,01) para todos os cortes obtidos. Quanto às análises intragrupos, notou-se diferença estatística significante apenas no grupo I (p < 0,01), porém os cortes executados em 6 mm e 9 mm foram iguais (p > 0,05). Conclusão: Das técnicas de obturação de canais radiculares testadas, a híbrida de Tagger possui a maior capacidade de preenchimento do sistema de canais radiculares com guta-percha. Depois vêm as técnicas da compressão hidráulica e da condensação lateral

Introduction and objective: The aim of this study was to determine gutta-percha's root canal filling capacity through three different filling techniques. Material and methods: Sixty single-rooted human teeth were cleaned, shaped and randomly divided according to the filling technique: Group I: Lateral condensation; Group II: Hydraulic compression; Group III: Tagger's hybrid. All procedures were performed by two previously calibrated operators. The teeth were transversely sectioned into four cuts, starting from the root apex (at 3 mm, 6 mm, 9 mm, and 12 mm), by using an Isomet diamond blade (wafering blade, series 15 high concentration, 5 inch blade, Buehler Ltd., Lake Bluff, IL, USA), mounted in an IsoMet® Low Speed Saw (Buehler Ltd., Lake Bluff, IL, USA), and water as a cooling medium. Each group's cut was embedded in acrylic resin and polished. Root canal images were captured and then analysed by Image Tool 3.0 software (Department of Dental Diagnostic Science, University of Texas, Health Science Center, San Antonio, Texas). Measurements of root canal overall area and gutta-percha-filled area were executed, therefore, obtaining the percentage of gutta-percha's root canal filling capacity for each slice. Results: Data were analyzed by GMC software 10.0 and Kruskal-Wallis test. Tagger's hybrid technique (95.1%) was superior to the other two techniques, followed by Hydraulic compression (89.1%) and lateral condensation (70.6%). The results were statistically different among the three techniques, for all cuts (p < 0.01). Intra-group analyses showed statistically significant differences only in Group I (p < 0.01). However, slices obtained at 6 mm and 9 mm were statistically equal (p > 0.05). Conclusion: These results suggest that Tagger's hybrid technique may yield better root canal filling capacity than Hydraulic compression and lateral condensation technique, which showed the worst filling capacity of all the three techniques employed

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.