DOES THE ACTIVATION OF ROOT CANAL DRESSINGS IMPROVE THEIR FILLING QUALITY ON TEETH WITH SIMULATED INTERNAL ROOT RESORPTION?

This study aims to evaluate, by micro-computed tomography, the filling capacity of two root canal dressings (RCD) - Bio-C Temp and Ultracal - after different activation protocols in teeth with simulated internal root resorption. Eighty single-rooted bovine teeth were sectioned in the cervical portion, standardizing the roots at 16 mm. Then, the canals were prepared by the apex-crown technique until instrument #80 using 2mL of 2.5% sodium hypochlorite solution at each instrument change. Afterward, the roots were sectioned longitudinally, and internal root resorptions were simulated using a diamond bur 1016 at 5 mm from the root apex. Hemiroots were joined and fixed with cyanoacrylate, scanned in micro-computed tomography (micro-CT) to assess total canal volume and simulated internal resorption, and then divided by stratified randomization into experimental groups according to RCD and method of activation (n = 10): Ultracal/Syringe; Ultracal/PUI, Ultracal/XP Endo Finisher, Ultracal Easy Clean, Bio-C Temp/Syringe, Bio-C Temp/PUI, Bio-C Temp/XP Endo Finisher and Bio-C/Easy Clean. Another scanning was performed to assess the volume of voids after RCD activation methods. The ANOVA and Tukey tests compared the activation methods. Student's T-test compared the RCDs within each activation method. Initial root canal volume values were similar for all groups (P > 0.05). There was no difference between activation protocols (P > 0.05). Higher volumes of void spaces were observed for Bio-C Temp compared to Ultracal after all activation methods (P < 0.05), except for Easy Clean (P > 0.05). Due to this, it can be concluded that the agitation methods tested for the Bio-C Temp and Ultracal pastes did not improve the filling of bovine teeth with simulated internal root resorption.

DOES THE ACTIVATION OF ROOT CANAL DRESSINGS IMPROVE THEIR FILLING QUALITY ON TEETH WITH SIMULATED INTERNAL ROOT RESORPTION?

Aims: This study aims to evaluate, by micro-computed tomography, the filling capacity of two root canal dressings (RCD) -Bio-C Temp and Ultracal -after different activation protocols in teeth with simulated internal root resorption.Materials and methods: Eighty single-rooted bovine teeth were sectioned in the cervical portion, standardizing the roots at 16 mm. Then, the canals were prepared by the apex-crown technique until instrument #80 using 2mL of 2.5% sodium hypochlorite solution at each instrument change. Afterward, the roots were sectioned longitudinally, and internal root resorptions were simulated using a diamond bur 1016 at 5 mm from the root apex. Hemiroots were joined and fixed with cyanoacrylate, scanned in micro-computed tomography (micro-CT) to assess total canal volume and simulated internal resorption, and then divided by stratified randomization into experimental groups according to RCD and method of activation (n = 10): Ultracal/Syringe; Ultracal/PUI, Ultracal/XP Endo Finisher, Ultracal Easy Clean, Bio-C Temp/Syringe, Bio-C Temp/PUI, Bio-C Temp/XP Endo Finisher and Bio-C/Easy Clean. Another scanning was performed to assess the volume of voids after RCD activation methods. The ANOVA and Tukey tests compared the activation methods. Student's T-test compared the RCDs within each activation method. Initial root canal volume values were similar for all groups (P > 0.05).Results:There was no difference between activation protocols (P > 0.05). Higher volumes of void spaces were observed for Bio-C Temp compared to Ultracal after all activation methods (P < 0.05), except for Easy Clean (P > 0.05).Conclusion:It can be concluded that the agitation methods tested for the Bio-C Temp and Ultracal pastes did not improve the filling of bovine teeth with simulated internal root resorption.

DOES THE ACTIVATION OF ROOT CANAL DRESSINGS IMPROVE THEIR FILLING QUALITY ON TEETH WITH SIMULATED INTERNAL ROOT RESORPTION?

Aims: This study aims to evaluate, by micro-computed tomography, the filling capacity of two root canal dressings (RCD) -Bio-C Temp and Ultracal -after different activation protocols in teeth with simulated internal root resorption.Materials and methods: Eighty single-rooted bovine teeth were sectioned in the cervical portion, standardizing the roots at 16 mm. Then, the canals were prepared by the apex-crown technique until instrument #80 using 2mL of 2.5% sodium hypochlorite solution at each instrument change. Afterward, the roots were sectioned longitudinally, and internal root resorptions were simulated using a diamond bur 1016 at 5 mm from the root apex. Hemiroots were joined and fixed with cyanoacrylate, scanned in micro-computed tomography (micro-CT) to assess total canal volume and simulated internal resorption, and then divided by stratified randomization into experimental groups according to RCD and method of activation (n = 10): Ultracal/Syringe; Ultracal/PUI, Ultracal/XP Endo Finisher, Ultracal Easy Clean, Bio-C Temp/Syringe, Bio-C Temp/PUI, Bio-C Temp/XP Endo Finisher and Bio-C/Easy Clean. Another scanning was performed to assess the volume of voids after RCD activation methods. The ANOVA and Tukey tests compared the activation methods. Student's T-test compared the RCDs within each activation method. Initial root canal volume values were similar for all groups (P > 0.05).Results:There was no difference between activation protocols (P > 0.05). Higher volumes of void spaces were observed for Bio-C Temp compared to Ultracal after all activation methods (P < 0.05), except for Easy Clean (P > 0.05).Conclusion:It can be concluded that the agitation methods tested for the Bio-C Temp and Ultracal pastes did not improve the filling of bovine teeth with simulated internal root resorption

The effectiveness of rotary and reciprocating techniques in curved root canals retreatment: a micro- CT analysis

Introduction: Different NiTi rotary systems have been developed to improve efficiency and retreatment success rates. Aim: To evaluate the Protaper Universal retreatment system and WaveOne instrument in removing the filling material from curved canals during retreatment. Materials and Methods: Thirty mesial root canals of extracted human mandibular molar teeth were randomly allocated into 2 groups (n=15). In the PT group, retreatment was performed with ProTaper Universal Retreatment according to the manufacturer's instructions. In the WO group, was used WaveOne Primary. ProTaper Universal F2 and F3 were used to achieve the apical diameter in both groups. The samples were scanned by micro-computed tomography pre and postoperatively to evaluate the filling material remaining. The percentage of material filling was compared between groups using Student's T test and in the same group among thirds was compared using Kruskal-Wallis followed by Dunn's post hoc test. Results: The filling material remaining was not statistically different between the groups (p≥0.05). The apical third presented a greater amount of remaining filling material when compared with the cervical third for both groups (p<0.05). Conclusion: Rotary and reciprocating techniques can effectively, but not completely, remove the filling materials from the root canal system. The apical third presented a more significant amount of remaining filling material.

Efeito do hipoclorito de cálcio na resistência de adesão do cimento obturador AH Plus à dentina / Effect of calcium hypochlorite on the bond strength of the AH Plus sealer to dentin

Objetivo: avaliar o efeito do uso de hipoclorito de cálcio (Ca(OCl)2) como irrigante na resistência de adesão do cimento AH Plus (De Trey-Dentsply, Konstanz, Alemanha) à dentina pelo teste de micro push-out. Materiais e método: trinta e três dentes humanos monorradiculares foram seccionados transversalmente na junção amelocementária e divididos em três grupos: hipoclorito de sódio (NaOCl) 2,5%, hipoclorito de cálcio 2,5% e soro fisiológico. Os canais foram preparados, irrigados ao final com EDTA 17% e obturados com cones de guta percha e cimento AH Plus. Após armazenagem por 7 dias, em 100% de umidade e a 37°C, os dentes foram seccionados transversalmente ao longo do eixo da raiz. Foram obtidas três fatias de cada dente (n=33), que foram submetidas ao ensaio de push-out. O tipo de falha foi analisado por fractografia e classificado em falha adesiva, coesiva ou mista. Os valores de resistência de união foram analisados pelo teste de Kruskal-Wallis, com nível de significância de 95%. Resultados: o grupo Ca(OCl)2 2,5% apresentou a menor média de resistência de adesão, diferindo estatisticamente do NaOCl e do soro fisiológico (p<0,05). Não houve diferença estatística entre os grupos irrigados com soro e NaOCl (p>0,05). Conclusões: a falha predominante em todos os grupos foi a do tipo adesiva. O Ca(OCl)2 2,5% teve um efeito negativo sobre a força de adesão do AH Plus à dentina radicular quando comparado ao NaOCl 2,5%. (AU)

Objective: to evaluate the effect of calcium hypochlorite (Ca(OCl)2) as an irrigant on the bond strength of the AH Plus sealer (De Trey-Dentsply, Konstanz, Germany) to dentin, using the micro push-out test. Materials and method: thirty-three single-rooted human teeth were cross-sectioned on the cementoenamel junction and divided into three groups: 2.5% sodium hypochlorite (Na- OCl), 2.5% calcium hypochlorite, and saline solution. The canals were prepared, irrigated with 17% EDTA at the end, and filled with gutta-percha cones and AH Plus sealer. After being stored for seven days at 100% humidity and 37ºC, the teeth were cross-sectioned along the root axis. Three slices of each tooth (n=33) were obtained and subjected to the push-out test. Failure mode was analyzed by fractography and classified as adhesive, cohesive, or mixed. Bond strength values were analyzed by the Kruskall-Wallis test at 95% significance level. Results: the 2.5% Ca(OCl)2 group showed the lowest bond strength mean, differing statistically from 2.5% NaOCl and saline solution (p<0.05). There was no statistical difference between the groups irrigated with saline solution and NaOCl (p>0.05). Conclusion: the adhesive failure was predominant in all groups. The 2.5% Ca(OCl)2 had a negative effect on the bond strength of AH Plus to the root dentin when compared to 2.5% NaOCl. (AU)