Avaliação de protocolos de irrigação ultrassônica passiva na remoção de detritos do canal radicular / Evaluation of passive ultrasonic irrigation protocols in the removal of root canal debris

Introdução: O objetivo deste estudo foi avaliar a eficácia de diferentes protocolos de Irrigação Ultrassônica Passiva (PUI) por meio de microscopia eletrônica de varredura (MEV). Métodos: Seis cavidades foram confeccionadas ao longo da seção vestibular de 20 canais radiculares de pré-molares inferiores humanos e preenchidas com detritos. 10 grupos foram criados de acordo com o protocolo final de irrigação: Grupo 1- controle positivo (sem detritos); Grupo 2- controle negativo (com detritos); Grupo 3 - irrigação convencional com hipoclorito de sódio a 2,5% (NaOCl); Grupo 4 - irrigação convencional com 17% de ácido etilenodiaminotetracético (EDTA) seguido de NaOCl; Grupo 5- PUI com 3 ciclos de 20 segundos (NaOCl-NaOCl-NaOCl); Grupo 6- PUI com 3 ciclos de 20 segundos (NaOCl-EDTA-NaOCl); Grupo 7- PUI com um ciclo de 60 segundos (NaOCl); Grupo 8 - PUI com ciclo de 180 segundos (NaOCl); Grupo 9 - PUI com 2 ciclos de 60 segundos (EDTA-NaOCl); Grupo 10 - PUI com 2 ciclos de 60 segundos (NaOCl-EDTA). Os espécimes foram observados em MEV para a análise da remoção dos detritos (scores 1 a 5) e exposição dos túbulos dentinários (score 1 ou 2) dentro das cavidades. O teste de Kruskal-Wallis foi realizado para a análise estatística, com significância de 5%. Resultados: Os grupos PUI apresentaram melhores resultados na limpeza de detritos do que os grupos de irrigação convencionais nas cavidades 1, 2 e 3. As cavidades 4, 5 e 6 foram limpas em todos os grupos experimentais. Em relação à exposição dos túbulos dentinários, os grupos PUI foram capazes de alcançar um resultado melhor do que os grupos de irrigação convencional. Conclusões: A PUI mostrou-se mais eficaz na remoção de detritos do que a irrigação convencional nas cavidades localizadas na região apical do canal radicular, e os grupos PUI promoveram maior exposição dos túbulos dentinários independentemente do uso de EDTA como agente quelante para tecidos inorgânicos(AU)

Introduction: The aim of this study was to evaluate the effectiveness of different Passive Ultrasonic Irrigation (PUI) protocols by means of scanning electron microscopy. Methods: Six hemispherical cavities were made along the buccal section of 20 root canals of human lower premolars and filled with debris. 10 groups was created according to the final irrigation protocol: Group 1- positive control (no debris); Group 2- negative control (with debris); Group 3- conventional irrigation with 2.5% sodium hypochlorite (NaOCl); Group 4- conventional irrigation with 17% ethylenediamine tetracetic acid (EDTA) followed by NaOCl; Group 5- PUI with 3 cycles of 20 seconds (NaOCl-NaOCl-NaOCl); Group 6- PUI with 3 cycles of 20 seconds (NaOCl-EDTANaOCl); Group 7- PUI with a 60 seconds cycle (NaOCl); Group 8- PUI with a 180 seconds cycle (NaOCl); Group 9- PUI with 2 cycles of 60 seconds (EDTA-NaOCl); Group 10- PUI with 2 cycles of 60 seconds (NaOCl-EDTA). Scores were given for the analysis of debris removal in SEM, as well as for the exposure of dentinal tubules within the cavities. Kruskal-Wallis test was performed for statistical analysis. Results: The PUI groups presented better results in cleaning of debris than the conventional irrigation groups in cavities 1, 2 and 3. Cavities 4, 5 and 6 were well cleansed in all experimental groups. Regarding the exposure of the dentinal tubules, the PUI groups were able to achieve a better result than the conventional irrigation groups. Conclusions: Passive ultrasonic irrigation proved to be more effective in the removal of debris than conventional irrigation in the cavities located in the apical region of the root canal, and the PUI groups promoted greater exposure of the dentinal tubules independently of the use of EDTA as a chelating agent for inorganic tissues(AU)

Hypertension affects the biocompatibility and biomineralization of MTA, High-plasticity MTA, and Biodentine®

Abstract This study evaluated the effect of hypertension on tissue response and biomineralization capacity of white Mineral Trioxide Aggregate (MTA), High-plasticity MTA (MTA HP), and Biodentine® (BDT) in rats. Polyethylene tubes filled with MTA, MTA HP, BDT, and the control group (empty tubes) were placed into the dorsal subcutaneous tissue of 32 male rats (16 normotensive (NT) and 16 hypertensive rats - 8 per group). After 7 and 30 days, the polyethylene tubes surrounded by connective tissue were removed, fixed, and embedded in histological resin. The mean number of inflammatory cells was estimated in HE-stained sections, biomineralization was quantified as area (µm2) by Kossa (VK) staining, and examination by polarized light (LP) microscopy was performed. The differences amongst the groups were analyzed statistically by the Mann-Whitney or Student's t test, according to Shapiro-Wilk test of normality (p < 0.05). The inflammatory responses to all materials were greater in hypertensive rats than in NT rats (p < 0.05). Positive VK staining in MTA and BDT were more pronounced in NT rats at 7 and 30 days (p < 0.05). Birefringent structures in LP for MTA, MTA HP, and BDT were more pronounced in NT rats at 7 days (p<0.05). In rats, hypertension was able to increase inflammatory infiltrate and decrease biomineralization of the tested materials.