Retracted: Micro-computed tomography evaluation of apical transportation and centring ability of Reciproc and WaveOne systems in severely curved root canals.

The following article from International Endodontic Journal, 'Micro-computed tomography evaluation of apical transportation and centring ability of Reciproc and WaveOne systems in severely curved root canals' by D. A. de Meireles, T. C. C. A. de Brito, A. A. F. Marques, A. D. B. Garrido, L. F. R. Garcia & E. C. Sponchiado Jr, published online on 5 February 2015 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor in Chief, Prof. Paul Dummer, and John Wiley & Sons Ltd. The retraction has been agreed due to the use of techniques for crucial measurements in canal shaping and a lack of clarity regarding the measuring methodology. The use of inadequate measuring methodologies makes the findings of the paper invalid.

Laboratory evaluation of the physicochemical properties of a new root canal sealer based on Copaifera multijuga oil-resin.

AIM: To compare a new root canal sealer based on Copaifera multijuga oil-resin (Biosealer) using three other established sealers (Sealer 26, Endofill and AH plus) in terms of their physicochemical properties. METHODOLOGY: The study was carried out according to the requirements of Specification Number 57 of the American Dental Association (ADA) and consisted of the following tests: setting time, flow, film thickness, dimensional stability, radiopacity and solubility/disintegration. Data were analysed statistically using anova and Tukey's test for multiple comparisons. The significance level was set at 5% for all analyses. RESULTS: Sealer 26 and AH Plus had the longest setting time (P < 0.05). All materials presented flow in with the ADA's guidelines. Regarding film thickness, Sealer 26 did not have a satisfactory performance, as it had a higher mean value than the maximum allowed by the ADA (0.05 mm), being significantly different from the other materials (P < 0.05), which had mean values for film thickness in accordance with the ADA's recommendations. Regarding the solubility and disintegration, only Endofill did not meet the ADA's specifications and presented the worst results of all materials (P < 0.05). Sealer 26 presented the greatest dimensional changes and differed significantly from all other sealers (P < 0.05). Biosealer had the lowest radiopacity values and was significantly different from the other sealers (P < 0.05). CONCLUSION: The experimental sealer based on Copaifera multijuga oil-resin presented satisfactory results in the physicochemical tests required by the ADA.

Evaluation of several protocols for the application of ultrasound during the removal of cast intraradicular posts cemented with zinc phosphate cement.

AIM: To evaluate several protocols for the application of ultrasound during removal of cast posts with varying core configurations cemented with zinc phosphate. METHODOLOGY: Sixty maxillary canines were distributed into three groups (n = 20): group 1 - core with 5 mm diameter/height and post diameter of 1.3 mm; groups 2 and 3 - core with the same diameter as the post (1.3 mm) and heights of 5 mm and 3 mm, respectively. Posts/cores were cemented using a standard technique with zinc phosphate cement. Each group was divided into two subgroups according to the ultrasonic vibration mode: point vibration - ultrasonic vibration applied to the core surface for 5 s, on each face totalling 25 s; alternate vibration - intermittent application of ultrasonic vibration for 10 s to the labial and lingual surfaces, 10 s to the mesial and distal surfaces and 5 s to the incisal surface, totalling 25 s. The specimens were submitted to the tensile test using an Instron machine (1 mm min(-1)) and results were analysed by anova and t-test. The failure type was also analysed. RESULTS: Statistical analysis showed significant differences between groups relating to the core preparations (P < 0.05). The lowest mean values of traction force were obtained for group 3 (46.1 +/- 7.7 N), followed by group 2 (89.0 +/- 2.7 N) and group 1 (160.4 +/- 7.5 N). Regarding ultrasonic vibration, the lowest mean was observed with alternate vibration (81.1 +/- 10.1 N), which was significantly lower than the point vibration (115.9 +/- 9.5 N) (P < 0.05). Cohesive failure occurred in all cases. CONCLUSION: A reduction in core diameter/height and intermittent ultrasonic application improved the removal of cast posts cemented with zinc phosphate.

Clinical aspects of pulpal-periodontal lesions.

It is well known that the main purpose of dentistry is to keep teeth in the oral cavity so that they may fulfill their various roles. This case report demonstrates a method to treat a situation involving a pulpal-periodontal lesion, by using a simple and efficient combined therapy. The clinician can thereby determine the cause of the lesion (pulpal and/or periodontal) and subsequently establish the correct treatment, thus improving the prognosis of the case.

In vitro evaluation of the effect of core diameter for removing radicular post with ultrasound.

The removal of radicular posts for endodontic reasons as well as their replacement is a common procedure in dental practice. The use of ultrasound is becoming a standard practice since it reduces the stress to displace the core from the canal minimizing the risks of root fractures, perforations and further wearing of dental structure. Thus, the objective of this study was to evaluate the effect of a reduction in the core diameter when removing radicular posts with ultrasound. Twenty-four teeth were divided in two groups. Group I received posts with the dowel and core of the same diameter (1.7 mm) and group II received posts with the dowel diameter 2 mm larger (3.7 mm) than the core diameter. Zinc phosphate cement was used to cement the posts in all groups. Half of the samples of each group received ultrasonic energy for 8, 2 min for each face. All samples were submitted to traction on an Instron machine (model 4444). Data were analysed statistically with anova and the Tukey test, revealing significant differences (P < 0.05) between groups. The authors concluded that the mean tension necessary to displace the posts from the roots was reduced by 26% when ultrasound was applied. The reduction of the post-diameter reduced the necessary tension to remove them by 24% compared with larger posts.