Efficacy of different techniques for removal of calcium hydroxide-chlorhexidine paste from root canals.

The purpose of this study was to evaluate the efficacy of different techniques for removal of combined calcium hydroxide [Ca(OH)2] and chlorhexidine paste from root canals. Fifty single-rooted human teeth were prepared by oscillatory and rotary systems and filled with a paste of Ca(OH)2 and 2% chlorhexidine gel. After incubation for 14 days, the specimens were divided into 5 groups (n = 10), and the medication was removed by 1 of 5 different procedures. In group 1 (control), removal procedures involved a master apical file, foraminal debridement, and 5 mL of saline solution applied with the NaviTip irrigation needle. Group 2 was treated the same as group 1, but in addition 0.5 mL of 17% ethylenediaminetetraacetic acid was used for 3 minutes. In group 3, ultrasonic agitation was performed for 1 minute. Group 4 was treated as group 2, but the NaviTip FX needle was used for irrigation. In group 5, a master apical file, foraminal debridement, and 3-minute application of 5 mL of citric acid were used. After the root-cleaning procedures, the crowns were removed at the cementoenamel junction, and the roots were split longitudinally into halves. The success of intracanal medicament removal was observed under stereoscopic microscope and scanning electron microscope. Remnants of Ca(OH)2 were found in all experimental groups, regardless of the removal technique used. There was no statistically significant difference in cleanliness in the apical third of the root canal among groups 1, 2, and 3. Group 4 showed the best and group 5 the worst results with statistically significant differences. Overall, the NaviTip FX irrigation needle technique was more efficient in removing a Ca(OH)2-chlorhexidine paste from the root canal.

Effect of root perforations on the bond strength of fiberglass post using different adhesive systems and resin cement / Efeito das perfurações radiculares na resistência de união de pinos de fibra de vidro utilizando diferentes sistemas adesivos e cimento resino

Objective: This study evaluated the effect of root perforations on the bond strength of fiberglass posts cemented to the root canal with two adhesive systems and resin cement. Material and Methods: Forty single-rooted human teeth received endodontic treatment and were prepared for the cementation of fiberglass posts (Exacto Mini, Angelus). The teeth were divided into four experimental groups (n = 10) according to the root condition (with or without perforation) and the adhesive system used: G1: without perforation + Adper Single Bond 2 (3M ESPE), G2: without perforation + Clearfil SE Bond (Kuraray), G3: with perforation + Adper Single Bond 2, G4: with perforation + Clearfil SE Bond. The perforation was executed on the root surface with a diamond bur and sealed with white mineral trioxide aggregate (MTA). The specimens were sectioned and a push-out test was carried out (1 mm/min speed and 50 kgf). The data were statistically analyzed by ANOVA and Tukey Test (5%). Results: Adper Single Bond 2 promoted the greatest values of bond strength to the roots without root perforation. The presence of root perforation led to the reduction in bond strength values regardless of the bonding system used (p < 0.05). Conclusion: The root perforations caused a direct effect on the bond strength of the fiberglass posts cemented by reducing the bond strength values to the root dentin regardless of the adhesive system used.

Objetivo: O objetivo deste estudo foi avaliar o efeito das perfurações radiculares na resistência de união de pinos de fibra de vidro cimentados com dois sistemas adesivos e um cimento resinoso. Material e Métodos: Quarenta dentes humanos unirradiculares receberam tratamento endodôntico e foram preparados para cimentação de pinos de fibra de vidro (Exacto Mini, Angelus). Os dentes foram divididos em quatro grupos experimentais (n = 10) de acordo com a condição radicular (com ou sem perfuração) e o sistema adesivo utilizado: G1: sem perfuração + Adper™ Single Bond 2; G2: sem perfuração + Clearfil SE Bond; G3: com perfuração + Adper™ Single Bond 2; G4: com perfuração + Clearfil SE Bond. A perfuração foi realizada na superfície radicular com uma ponta diamantada e selada com agregado de trióxido mineral branco (MTA). Os espécimes foram seccionados para realização do teste de extrusão por cisalhamento (Push-out) com velocidade de 1 mm/ min e célula de carga de 50 Kgf. Os dados obtidos foram submetidos à Análise de Variância (ANOVA) e Teste de Tukey a 5%. Resultados: O sistema adesivo Adper Single Bond 2 promoveu os maiores valores de resistência de união nas raízes sem perfuração radicular. A presença de perfuração promoveu redução nos valores de resistência de união, independentemente do sistema adesivo utilizado (p < 0,05). Conclusão: As perfurações radiculares causaram efeito direto sobre a resistência de união dos pinos de fibra de vidro, promovendo redução nos valores da resistência de união independentemente do tipo de sistema adesivo utilizado.