Efficacy of reciprocating systems for removing root filling material plus complementary cleaning methods in flattened canals: Microtomography and scanning electron microscopy study.

The aim of this study was to evaluate three reciprocating systems and complementary cleaning methods on filling material removal during retreatment of flattened canals. Thirty-six mandibular incisors were prepared using rotary instruments up to size 25.08 and filled using the single-cone technique. Subsequently, the teeth were divided into three groups (n = 12) according to retreatment procedures: Reciproc Blue (RB): 25/0.08 and 40/0.06; ProDesign R (PDR): 25/0.06 and 35/0.05; and WaveOne Gold (WOG): 25/0.07 and 35/0.06. The remaining filling volume materials were assessed by means of micro-CT imaging before and after retreatment. After this, the specimens were subdivided into three groups according to complementary cleaning methods: XP-Endo Shaper (30/0.01); passive ultrasonic irrigation (PUI); 60° oscillatory instrumentation with #30 H-file, and micro-CT scan was taken. Then, the roots were cut in half and the samples were analyzed by scanning electron microscope (SEM). The data were analyzed statistically using Kruskal-Wallis and Dunn's Multiple Comparison test with significance level of 5%. None of the reciprocating files promoted complete removal of filling material and there was no statistical difference between the groups, regardless instrument size (p > 0.05). Complementary cleaning methods increased remnant filling removal (p < 0.05). XP-endo Shaper significantly reduced the amount of filling material in the apical and middle thirds, compared with H-files (p < 0.05), with no difference with PUI. In the SEM, there was no statistical difference among the instruments (p > 0.05). The reciprocating systems showed similar effectiveness in removing root filling material. Complementary cleaning method with the XP-Shaper enhanced filling material removal.

Avaliação da precisão de dois localizadores foraminais na determinação do limite apical: estudo in vitro / Evaluation of the accuracy of two apex locators in determining apical limit: an in vitro study

O objetivo do presente estudo foi comparar in vitro a precisão de dois localizadores foraminais: Endus (Gnatus, Ribeirão Preto, SP, Brasil) e Root ZX (J. Morita, Tokyo, Japão). Material e Método: Trinta e dois dentes caninos permanentes humanos foram selecionados para o estudo. Após a realização da abertura coronária e preparo do terço cervical e médio, procedeu-se à determinação do comprimento real do dente pelo método visual, com introdução de um instrumento tipo K #10 até ser visto na saída foraminal sob magnificação de 16x com microscópio óptico de luz (DF Vasconcelos, São Paulo, Brasil). Para medição eletrônica, os dentes foram inseridos em um molde de alginato e as medidas realizadas com os dois localizadores foraminais até a saída do forame apical (0,0mm). Resultados: Os resultados evidenciaram um índice de precisão de 96,8% e 91,6% para os localizadores Gnatus e Root ZX, respectivamente. Conclusão: Ambos os localizadores apicais eletrônicos testados apresentaram alto índice de precisão na determinação do limite apical.

The aim of this study was to compare in vitro the precision of two locators foraminal: Endus (Gnatus, Ribeirão Preto, SP, Brazil) and Root ZX (J. Morita, Tokyo, Japan). Methods: Thirty-two canine teeth permanent humans were selected for the study, and, after effectuate the coronary opening and preparation of the cervical and middle third, proceeded to the determination of the real length of the tooth by the visual method, introducing an instrument file K #10 until be seen in foraminal exit under magnification of 16x optical light microscope (DF Vasconcelos, São Paulo, Brazil). For electronic measurement, the teeth were embedded in an alginate mold and electronic measurements with the two locators foraminal to the actual output of the apical foramen (0,0mm). Results: The results showed a 96.8% and 91.6% accuracy rates for the locators Gnatus and Root ZX, respectively. Conclusion: Both electronic apex locators tested presented high index of precision in the precise of determination in the apical limit.