Efficacy of Passive Ultrasonic Activation in Removing Calcium Hydroxide from Simulated Internal Resorption Cavities at Different Root Regions.

AIMS: The aim of this study was to evaluate the effect of passive ultrasonic activation on calcium hydroxide removal from simulated internal root resorption (IRR) cavities at different root levels. METHODS AND MATERIAL: Sixty mandibular canines were prepared and divided into 3 groups to create IRR cavities at apical, middle, coronal root levels. The cavities filled with calcium hydroxide (CH). Specimens were divided into two subgroups according to the technique used for CH removal: Passive ultrasonic activation (PUA), Classic syringe irrigation (CSI). The cavities were photographed with a stereomicroscope, and percentage of remaining CH was measured using digital image analysis software (Image J). Statistical analysis was performed with two-way ANOVA and post-hoc Duncan tests. RESULTS: PUA removed significantly more CH at apical and middle levels. (p < 0.05) There was no significant difference between PUA and CSI at coronal level. (p > 0.05) In PUA group, the amount of residual CH was the highest at coronal level. (p < 0.05) In CSI group, the amount of residual CH was the highest at apical level. (p < 0.05). CONCLUSIONS: None of the tested technique was able to completely remove CH from the simulated IRR cavities. CH was removed better with PUA than CSI at middle and apical root levels. For both techniques, the best results were obtained at middle root level.

The effect of nonthermal plasma on the push-out bond strength of two different root canal sealers.

BACKGROUND: An optimum bonding between the sealer and dentin is important for impermeable root canal filling and many procedures were applied to improve root canal dentin and in turn the bond strength between the sealer and dentine. There is lack of sufficient data on the effect of nonthermal plasma application on the bond strength of sealers to the root canal dentin. AIM: The purpose of this study was to evaluate the effect of NAP on the push-out bond strength (PBS) of a bioceramic and resin-based root canal sealer (RCS) to root canal dentin. MATERIALS AND METHODS: Forty single-rooted mandibular premolars were decoronated. After preparation and final irrigation, the specimens were divided into four groups (n = 10). Group AH: Root canals were filled with gutta-percha (GP) and AH Plus RCS, Group P-AH: Root canals were filled with GP and AH Plus RCS following the NAP application, Group BC: Root canals were filled with GP and Endosequence BC RCS, and Group P-BC: Root canals were filled with GP and Endosequence BC RCS following the NAP application. Then roots were sectioned horizontally to obtain ~1 mm thick dentin disks. PBS test was performed to the second (coronal) and fourth (middle) slices. Data were analyzed with the Kruskal-Wallis and t-test. RESULTS: There was a statistically significant difference among the groups for both coronal and middle regions (P < 0.05). P-BC group showed higher PBS than AH and P-AH groups in the coronal region. P-BC group showed higher PBS than the other groups in the middle region. CONCLUSIONS: The use of NAP did not influence the push-out bond strength of AH-Plus sealer to the root canal dentin. The Endosequence-BC sealer showed a better bond strength than the AH-Plus sealer after NAP application.

The effect of cervical preflaring on the apical debris extrusion of single or multiple rotary Ni-Ti files.

BACKGROUND: There were no comparing data about the effect of recently developed file system OneCurve on apical debris extrusion. AIM: The aim of this in vitro study was to compare the influence of the rotary nickel-titanium (Ni-Ti) files on apical debris extrusion after cervical preflaring. MATERIALS AND METHODS: Sixty-six lower incisor teeth with a single root canal were used in this study. After the determination of working length, the specimens were divided into six experimental groups according to root canal preparation. G1: ProTaper-Next, G2: EndoFlare + ProTaper-Next, G3: 2Shape, G4: EndoFlare + 2Shape, G5: OneCurve, and G6: EndoFlare + OneCurve. Each specimen was inserted into separate preweighed Eppendorf tubes to collect apically extruded debris. A total of 8 mL of distilled water was used for each specimen for irrigation. After the completion of root canal preparation, the Eppendorf tubes were weighed again after evaporation to calculate the amount of extruded debris. The data were statistically analyzed with one-way analysis of variance (P > 0.05). RESULTS: There was no statistically significant difference between the experimental groups. The amount of apically extruded debris was similar after preparing root canals with ProTaper-Next, 2Shape, and OneCurve with and without cervical preflaring. CONCLUSION: Under the conditions of this in vitro study, ProTaper-Next, 2Shape, and OneCurve files had similar apical debris extrusion values. Cervical preflaring of root canals did not affect the amount of apically extruded debris.

Weight of apically extruded debris following use of two canal instrumentation techniques and two designs of irrigation needles.

AIM: To compare the weight of apically extruded debris associated with canal shaping using K-files, and the Revo-S system using two different needle tips, open-ended and side-vented. METHODOLOGY: Forty freshly extracted mandibular premolar teeth were divided into four groups as follows; Group 1a: Hand instrumentation of root canal with open-ended needle used to provide irrigation, Group 1b: Hand instrumentation with a two side-port needle, Group 2a: Revo-S preparation with open-ended needle, Group 2b: Revo-S preparation with a two side-port needle. One Eppendorf tube for each tooth was weighed with a 0.0001 electronic weighing machine before instrumentation procedures. During instrumentation, irrigation was performed after every instrument with 1 mL distilled water. On completion of the preparation, teeth were removed from the Eppendorf tubes. All of the tubes were incubated at 37 °C for 15 days, to evaporate the irrigant. After the incubation period, tubes were weighed again. The difference between pre-and post-debris weights was calculated, and statistical evaluation was performed using analysis of variance at 0.05 level of significance. RESULTS: No statistically significant difference was observed between K-files and the RevoS system. A significant difference was observed between needles (P < 0.05). Open-ended needles were associated with significantly more debris than side-vented needles (P < 0.05). CONCLUSIONS: Both hand and rotary canal instrumentation resulted in extrusion of debris beyond the apical foramen. No significant difference was observed between K-files and Revo-S system. Open-ended needles were associated with significantly more extruded debris than two side-port needles.