Bond strength of calcium silicate-based sealers to dentine dried with different techniques.

OBJECTIVE: To assess the influence of various canal-drying techniques on the push-out bond strength between radicular dentine and both MTA Fillapex and iRoot SP sealers. MATERIALS AND METHODS: Eighty extracted single-root teeth were instrumented with ProTaper Universal rotary instruments to a size F4. The teeth were randomly assigned to 1 of 4 groups as follows: group 1, excess fluid in the canals was removed using a Luer vacuum adapter; group 2, the canals were dried with a single paper point; group 3, the canals were dried with 3-5 paper points, and group 4, the canals were rinsed with 95% ethanol and then dried with 3-5 paper points. In each group, the specimens were subgrouped according to root canal sealer into either subgroup A (MTA Fillapex) or subgroup B (iRoot SP sealer). Horizontal sections (thickness 1 ± 0.1 mm) were obtained from each specimen and a push-out test was performed using a universal testing machine at a crosshead speed of 1 mm/min on root slices. Statistical analysis was done using the Kruskal-Wallis test and Dunn's test for pair-wise comparisons. p < 0.05 was considered statistically significant. RESULTS: Canals dried with only 1 paper point and obturated with the iRoot SP sealer (subgroup 2B) showed significantly higher bond strengths to the root canal wall compared to all other subgroups (p < 0.05), except for subgroup 1B (p > 0.05). CONCLUSIONS: The canal-drying technique influenced the adhesive bond strength between calcium silicate-based root canal sealers and the root canal wall.

Effect of unintentionally extruded mineral trioxide aggregate in treatment of tooth with periradicular lesion: a case report.

INTRODUCTION: This case report describes the effect of unintentionally extruded mineral trioxide aggregate (MTA) into periradicular lesions and tissues on the prognosis of periradicular healing in maxillary left central incisor with periradicular lesion. METHODS: A 17-year-old girl with a large periradicular lesion from the apices of her maxillary left central to lateral incisors was referred. Tooth #9 had an open apex, but tooth #10 was normal. Conservative root canal treatment was performed to tooth #10. The apical third of the canal of tooth #9 was filled with MTA as an apical plug because of open apex. During this procedure, a radiograph was taken, and it showed an excessive extrusion of MTA into the periradicular lesion. The remaining canal space was filled with gutta-percha and AH Plus sealer by using a lateral condensation technique. RESULTS: At follow-up examinations, the tooth was asymptomatic and radiographically showed repair of the lesion. Healing was achieved without any need for further endodontic surgical intervention. CONCLUSIONS: The results of this case showed that complete periapical healing is possible despite the extrusion of the MTA. This might be due to biologic properties of the MTA. Even so, extrusion of the filling material is not advocated.

Effect of smear layer and root-end cavity thickness on apical sealing ability of MTA as a root-end filling material: a bacterial leakage study.

OBJECTIVE: The aim of this study was to investigate the effect of the cavity thickness and smear layer on apical sealing ability of mineral trioxide aggregate (MTA) as a root-end filling material. STUDY DESIGN: Seventy single-rooted maxillary central teeth were used in this study. All teeth were instrumented to size 50 using a step-back technique. The selected teeth were randomly divided into 4 groups, each containing 15 experimental samples and 5 positive and 5 negative control samples. In the first and second groups (smear+), the teeth were irrigated with only 5.25% NaOCl. In the third and fourth groups (smear-), the teeth were irrigated with 17% EDTA and 5.25% NaOCl to remove the smear layer. Also, in the first and third groups, cavities were prepared as 3 mm. In the second and fourth groups, cavities were prepared as 5 mm. All the root-end cavities were then filled with MTA. Nail varnish was applied to all external root surfaces to the level of the resected root-ends to prevent lateral microleakage. Samples were sterilized in an ethylene oxide sterilizer for 12 hours. The apical 3-4 mm of the roots were immersed in brain heart infusion culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 hours with a suspension of Enterococcus faecalis. Bacterial leakage was monitored every 24 hours for 4 weeks. The data obtained were analyzed using a chi-squared test, with alpha = .05 as the level for statistical significance. RESULTS: There were no statistically significant differences in rate of bacterial leakage among the experimental groups at 1-4 weeks (P > .05). Also, there was no difference between the groups when the 2 thickness groups were combined (P > .05). However, there was statistically significant differences when the 2 smear groups were combined for 4-week observation periods (P < .05). Removal of the smear layer caused significantly more apical microleakage than when the smear layer was left intact for 4 weeks. CONCLUSION: The thickness of root-end cavity (3 or 5 mm) had no influence in the bacterial leakage of the root end filled with MTA. Removing the smear layer may not be necessary in root-end cavities filled with MTA.

Comparison of the sealing ability of three filling techniques in canals shaped with two different rotary systems: a bacterial leakage study.

OBJECTIVE: This study compared the sealing ability of 3 current filling techniques in root canals shaped with 2 different rotary systems. STUDY DESIGN: Eighty human extracted mandibular premolars were divided randomly into 2 similar groups of 40 each and instrumented with either ProTaper (Dentsply Maillefer, Tulsa, OK; group A) or Mtwo (VDW; Antaeos, Munich, Germany; group B) rotary systems. Each group was divided into 3 subgroups (n = 10) and 2 control groups (n = 5). Canals were filled either with the tapered single-cone technique (SC; subgroups A1 and B1), with lateral condensation (LC; subgroups A2 and B2), or warm vertical compaction (WVC; subgroups A3 and B3). AH Plus was used as a root canal sealer in all groups. Samples were sterilized in an ethylene oxide sterilizer for 12 hours. The apical 3-4 mm of the roots were immersed in brain-heart infusion culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 hours with a suspension of Enterococcus faecalis. Bacterial leakage was monitored every 24 hours for 8 weeks. The data obtained were analyzed using a chi-squared test, and P was set at .05. RESULTS: In group A, 70% of the specimens filled with SC (subgroup A1), 50% of the specimens filled with LC (subgroup A2), and 20% of the specimens filled with WVC (subgroup A3) leaked. There was no statistically significant difference between the subgroups (P > .05). In group B, bacterial leakage was observed in 50% of SC samples (subgroup B1), 40% of LC samples (subgroup B2), and 50% of WVC samples (subgroup B3). There was no statistically significant difference between subgroups B1, B2, and B3 (P > .05). There was also no statistically significant difference between group A and group B (P > .05). CONCLUSION: Filling with SC, LC, and WVC techniques in canals treated with ProTaper or Mtwo rotary instruments showed similar levels of sealing efficacy.