Shaping Ability of ProTaper Next, WaveOne, and Reciproc in Simulated Root Canals.

INTRODUCTION: The study aimed to compare the shaping and preservation of the original curvature of simulated curved root canals using the following instruments: Reciproc (Rcp), WaveOne (Wo), and the ProTaper Next system (Ptn). MATERIALS AND METHODS: A total of 45 resin blocks with simulated curved root canals were divided into three groups (n = 15), prepared using the Rcp (R25), Wo (25/0.8), and Ptn (X2) instruments. Standardized photographs were taken before and after canal instrumentation. After the superimposition of the images, the amount of resin removed from the curvature's inner and outer walls was measured at six apical levels, at intervals of 1 mm. The canals' angles of curvature before and after instrumentation were subtracted. RESULTS: There were no significant differences between the instruments in terms of the total amount of resin removed of the inner or outer walls of the apical curvature (p > 0.05). The Rcp instruments provided the best resin removed ratios between the walls. The means of the change in angle were as follows: Wo = 2.15°, Ptn = 0.92°, and Rcp = 0.21°. WaveOne caused significantly higher deviations than Rcp. CONCLUSION: All of the instruments demonstrated a tendency to straighten the simulated root canal. Instruments that use rotary movement achieved an effect similar to that of the reciprocating instruments in relation to change in angle. CLINICAL SIGNIFICANCE: Deviations from the original shape of the root canal could have a negative impact on the quality of a filling and consequently on the success of the endodontic treatment.

Fear and/or anxiety of children and parents associated with the dental environment.

AIM: To assess levels of anxiety in children concerning different dental instruments and equipment and to relate them with parents' anxiety levels moments before the appointment. MATERIALS AND METHODS: Fifty children from 4 to 12 years of age (average of 10±3.07) and their respective parents were evaluated. A facial scale was used to assess children's anxiety levels, while the Dental Anxiety Scale (DAS) was used to assess parents. Friedman test was applied to check any differences in children's anxiety levels relative to the equipment/instruments, and this was complemented by the use of the Wilcoxon test for two-by-two comparison. In order to assess correlation between parents' and their children's anxiety levels, the study used Spearman correlation coefficient. RESULTS: With regard to parents' anxiety levels, 4% resulted as null, 18% were low, 56% were moderate, and 22% were exacerbated; children's anxiety level results were: 52% light, 44% intermediate, and 4% intense. Anxiety levels related to instruments/equipment were, in descending order: carpule syringe > paediatric forceps > dental explorer > x-ray machine > rubber dam punch > high speed handpiece > rubber dam forceps > mouth mirror > clinical tweezers > dental chair. No correlation was found between parents' anxiety levels and those of their children (p=0.546). CONCLUSION: The instruments/equipment used in the assessment generated different anxiety levels in the children. No correlation was found between parents' anxiety levels and those of their children.

Periapical radiographs overestimate root canal wall thickness during post space preparation.

AIM: To evaluate differences between anatomic and radiographic measurements of root canal wall thickness (RCWT) after each root canal preparation stage during post placement. METHODOLOGY: Twenty mandibular premolars with a single canal were decoronated and the roots embedded in resin using a teflon muffle. Roots were sectioned horizontally at a pre-established level and canals were prepared for post placement. Endodontic hand files were used for root canal preparation, followed by Gates Glidden drills and Peeso reamers. Standardized radiographs and photographs at pre-established measurement levels were taken before preparation, after root canal instrumentation, after Gates Glidden preparation and after Peeso enlargement. All images were digitized and RCWT at the mesial and distal walls measured (IMAGETOOL 3.0). Differences between radiographic and anatomic measurements were analysed with paired t-tests. anova was used to compare the percentages of radiographic distortions. RESULTS: Regardless of the time-point evaluated, RCWT determined by radiographs were greater than the respective anatomic measurements (P < 0.05). The difference detected at each stage was similar and constant (P > 0.05). CONCLUSIONS: Throughout preparation for post placement, radiographic images overestimated the RCWT by approximately 25%, regardless of the clinical stage evaluated.