Shaping ability of BlueShaper, TruNatomy, DC Taper and HyFlex EDM in long oval canals: An ex vivo study.

AIM: This study evaluated and compared the shaping ability of four rotary instrument systems in long-oval root canals using microcomputed tomographic (micro-CT) evaluation. Currently, there is no data available on the canal shaping abilities of BlueShaper and DC Taper instruments. METHODOLOGY: Sixty-four single-rooted mandibular premolars were matched based on similar root canal morphologic features as determined by (micro-CT) and randomly assigned to 1 of 4 experimental groups (n = 16) according to the instrument system used: BlueShaper, TruNatomy, DC Taper and HyFlex EDM One File. Changes in the root canal surface and volume, remaining dentine thickness, and number of prepared areas were assessed. RESULTS: No significant differences were found amongst the four instrument systems for the parameters evaluated (p > .05). There was a significant reduction in the number of unprepared areas and the remaining dentine thickness after each increase in size of the instruments tested (p < .05). CONCLUSIONS: The four instrument systems perform similarly in long oval root canals. Although none could prepare all canal walls, larger preparations incorporated significantly more surfaces in the final shape.

Comparison of the marginal adaptation of zirconium dioxide crowns in preparations with two different finish lines.

PURPOSE: The purpose of this study was to evaluate the marginal adaptation of zirconium dioxide crowns in preparations with two different finish line configurations before and after porcelain firing cycles, after a glaze cycle, and after cementation. MATERIALS AND METHODS: Twenty human molar teeth were prepared to receive full crowns; ten were prepared with a 90° round shoulder and another ten with a 45° chamfer finish line. Zirconium dioxide copings were fabricated using CAD/CAM technology (Lava™ system). They were then veneered with a low-fusing glass-ceramic (IPS e.max® Ceram). Finally, they were glazed and cemented with a resin-composite cement (RelyX™ Unicem, Aplicap™). Measurements for marginal adaptation using stereomicroscopy (40×) were performed at four stages: copings (S1), after porcelain firing cycles (S2), after glazing (S3), and after cementation (S4). One-way ANOVA was used to assess the influence of the finish line design on the marginal adaptation in each stage. Two-way ANOVA with repeated measurements was performed to assess the influence on the marginal adaptation of the porcelain firing cycles, glaze firing cycle, and cementation. RESULTS: The measured marginal gap mean values for the shoulder group (µm) were: 50.13 (S1), 54.32 (S2), 55.12 (S3), and 59.83 (S4). The values for the chamfer group were: 63.56 (S1), 71.85 (S2), 74.12 (S3), and 76.97 (S4). When comparing marginal gaps between specimens with two different finish lines, differences were noticed at the four studied stages (p = 0.0165, p = 0.0027, p = 0.0009, and p = 0.0009, respectively). No differences were manifested in the marginal gap measurements of the shoulder group at the different stages of fabrication (p = 0.4335); however, in the chamfer group, differences were noticed between S1 and S3 (p = 0.0042). CONCLUSIONS: Marginal adaptation was influenced by the finish line design. The firing cycles significantly affected the chamfer group; nevertheless, the marginal gap was within the range of clinical acceptability.

Management of teeth with dens invaginatus and apical periodontitis: A case series.

BACKGROUND: Dens invaginatus is a dental anomaly that can predispose the tooth to pulp and periapical pathology. CASE DESCRIPTION: Different endodontists treated 6 maxillary incisors with dens invaginatus associated with apical periodontitis. Cone-beam computed tomography was used to help with diagnosis and treatment planning in most patients. Four patients received diagnoses of Oehlers type II dens invaginatus and the other 2 as type III. In some patients with type II, the invagination had to be perforated to permit access to the apical part of the true root canal. Both the true canal and the invagination (pseudocanal) were treated in all cases using an antimicrobial regimen based on chemomechanical preparation with sodium hypochlorite irrigation and supplementary disinfection approaches. Calcium hydroxide medication was used in all but 1 case. The root canal and invagination were often filled using thermoplasticized gutta-percha techniques, sometimes using an apical plug with a bioceramic material in teeth with large apical openings. All treated patients had favorable clinical and radiographic outcomes. PRACTICAL IMPLICATIONS: Regardless of the complex anatomic variations, common strategic therapeutic approaches were identified that might serve as recommendations for proper management of teeth with dens invaginatus and apical periodontitis. These approaches include cone-beam computed tomographic planning, aggressive disinfection using sodium hypochlorite ultrasonic or sonic activation and calcium hydroxide intracanal medication, and thermoplasticized gutta-percha obturation of both the root canal and invagination.

In Vivo Evaluation of 3 Electronic Apex Locators: Root ZX Mini, Apex ID, and Propex Pixi.

INTRODUCTION: The aim of this in vivo study was to compare the accuracy of 3 electronic apex locators (EALs) (Root ZX mini [J Morita Corp, Tokyo, Japan], Apex ID [SybronEndo, Glendora, CA], and Propex Pixi [Dentsply Maillefer, Ballaigues, Switzerland]) to determine the working length. METHODS: Thirty single-rooted human teeth that were scheduled for extraction were selected for the study. Electronic measurements were performed with the 3 EALs. After the teeth had been extracted, a #10 K-file was used to determine the actual working length, which was established at 0.5 mm short of the major foramen. The data were statistically analyzed with analysis of variance (α = 0.05). RESULTS: No significant differences were found among the experimental groups (P > .05). The mean distance from the actual working length to the file tip was 0.163 ± 0.032 mm when Root ZX mini was used, 0.343 ± 0.032 mm for Propex Pixi , and 0.012 ± 0.008 mm for Apex ID. CONCLUSIONS: Under the in vivo conditions of this study, no statistically significant differences were observed among the 3 EALs.