All instrumentation techniques extruded intracanal bacteria apically. No significant difference was found in the number of CFU among the engine-driven techniques; manual techniques extruded significantly more microorganisms.
The purpose of this study was to evaluate the effect of labial and palatinal gingiva on laser Doppler pulpal blood flow measurements. Twenty upper central incisor teeth determined to be vital from 20 volunteers were included into the study. To stabilize the probe, a laboratory-made acrylic splint positioned the probe labially on the cervical third of the tooth crown. We collected measurements without any gingival covering, and under three conditions: after application of an opaque paste on the labial gingiva, the palatal gingiva, or both the labial and palatal gingiva. The measurement values decreased 46% when there was opaque paste on labial gingiva, 10% on palatinal gingiva, and 63% on both. The decrease in the values when there was an opaque paste on palatinal gingiva was not statistically significant (p > 0.05). The differences between all other groups were statistically significant (p < 0.05). In these measurements, the contribution of labial gingiva to laser Doppler pulpal blood flow measurements is more than that of palatinal gingiva.
Background/purpose: The aim of the this study was to compare the amount of debris apically extruded during endodontic retreatment using two rotary nickeletitanium (NiTi) instruments (K3 and R-Endo) and Hedström files. Materials and methods: Forty-five extracted human mandibular premolar teeth were used in this study. Root canals of the teeth were filled before being randomly assigned to three groups. In group 1, gutta-percha was removed with K3 (SybronEndo, West Collins, CA, USA) rotary NiTi instruments. In group 2, gutta-percha was removed with R-Endo (Micro-Mega, Besançon, France) rotary NiTi instruments. In group 3, gutta-percha was removed using Hedström files (Dentsply Maillefer, Ballaigues, Switzerland). Debris extruded from the apical foramen was collected into Eppendorf tubes. The liquid inside the tubes was dried, and the debris in each group was weighed and compared. Data were statistically analyzed using one-way analysis of variance, and KruskaleWallis test and ManneWhitney U test. Results: Although all retreatment techniques resulted in apical extrusion, groups 1 and 2 produced significantly less apical extrusion than group 3 (P < 0.05). No statistically significant difference was found between groups 1 and 2 (P > 0.05). Conclusion: All retreatment techniques produced extruded debris during endodontic retreatment; however, both rotary NiTi systems were associated with less apical extrusion than manual instrumentation with Hedström files.
The objective of this study was to evaluate and compare the cytotoxicity and genotoxicity on human fibroblast cell lines of sodium hypochlorite (NaOCl), chitosan and propolis as root canal irrigating solutions. Human fibroblast cells were exposed to chitosan, propolis and NaOCl for 4 and 24 h. Cell viability was assessed by 2,3-bis-(2methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide, and oxidative DNA damage was assessed by determination of 8-hydroxydeoxyguanosine (8-OHdG) level with an ELISA kit. The data of cell cytotoxicity were analysed statistically using a test of one-way analysis of variance at a significance level of p < 0.05. In the NaOCI group, the 8-OHdG level was higher than in the chitosan group, but there was no statistical difference when compared with the other groups (p < 0.05). It was determined that the irrigation solutions were cytotoxic, depending on the dose and time. NaOCl was the most toxic solution after both 4and 24 h of exposure (p < 0.05). Chitosan and propolis may be alternatives to NaOCl for irrigation solutions, because they are both less toxic and produce less oxidative DNA damage.
Objective: The aim of this study was to evaluate the efficacy of R-Endo® and K3® rotary nickel-titanium instruments compared with manual instrumentation with H-files, with use of a solvent, for removal of gutta-percha during retreatment.
Study design: Forty five freshly extracted human single-rooted teeth, each with one root canal, were instrumented with K-files and filled using cold lateral compaction of gutta-percha and AH 26® sealer. The teeth were randomly divided into three groups of 15 specimens each. Removal of gutta-percha was performed with the following devices and techniques: Group 1 (H-files), Group 2 (R-Endo®), and Group 3 (K3®). The specimens were rendered transparent for the evaluation of the area of remaining gutta-percha/sealer in buccolingual and mesiodistal directions. Statistical analysis as performed by using one-way ANOVA and Kruskal-Wallis tests (p=0.05).
Results: All retreatment techniques used in this study left some filling material inside the root canal. Images in buccolingual and mesiodistal directions showed no significant differences between the groups (p>0.05).
Conclusions: Under the experimental conditions, the remaining filling material after retreatment was similar for each group.
Key words:Gutta-percha removal, K3®, NiTi, R-Endo®.
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