Comparison of ProTaper, RaCe and Safesider instruments in the induction of dentinal microcracks: a micro-CT study.

AIM: To evaluate ex vivo the incidence of microcracks in root dentine after canal preparation with ProTaper Universal (PTU), RaCe or Safesider instrumentation systems using microcomputed tomography (micro-CT). METHODOLOGY: Thirty freshly extracted mandibular molars with two separate mesial canals and foramina were used. The roots were allocated into three similar groups according to curvature angles and radii of the canals and lengths of the roots. Distal roots were removed and mesial roots were embedded in acrylic resin and instrumented with the PTU, RaCe or Safesider systems up to size 30 (F3 for PTU, size 30, 0.04 taper for RaCe and Safesider) for all instrumentation groups. Dentinal microcracks were evaluated on micro-CT images of the apical 10 mm of the roots with 1-mm intervals. Two experienced observers evaluated the images twice in a blinded fashion. The presence of dentinal microcracks (complete/incomplete cracks and craze lines) was noted and analysed statistically using McNemar and chi-square tests (P = 0.05). RESULTS: There were microcracks on uninstrumented root sections. All instrumentation systems significantly increased the number of dentinal microcracks when compared to preoperative specimens (P < 0.05). There were new microcracks on the postoperative samples. The PTU system (42%) led to greater number of post-instrumentation microcracks than Safesider (35%) and RaCe (25%) systems, respectively. The difference between PTU and RaCe system was significant (P < 0.05). CONCLUSIONS: All instrumentation systems significantly increased the number of microcracks compared with preoperative specimens. The PTU system generated more post-instrumentation dentinal microcracks than the RaCe system.

Shaping ability of two M-wire and two traditional nickel-titanium instrumentation systems in S-shaped resin canals.

AIMS: The aim of this study was to evaluate the shaping effects of two M-wire and two traditional nickel-titanium (NiTi) rotary systems in simulated S-shaped resin canals. SUBJECTS AND METHODS: Forty simulated S-shaped canals in resin blocks were instrumented with two traditional (ProTaper, Sendoline S5) and two M-wire (WaveOne, GT series X) NiTi systems according to the manufacturers' instructions. Ten resin blocks were used for each system. Pre- and post-instrumentation images were captured using a stereomicroscope and superimposed with an image program. Canal transportation, material removal, and aberrations were evaluated and recorded as numeric parameters. STATISTICAL ANALYSIS USED: Data were analyzed using one-way ANOVA and post-hoc Tukey tests with a 95% confidence interval. RESULTS: There were significant differences between systems in terms of transportation and material removal (P<0.05). Coronal danger zone was the most common aberration. CONCLUSIONS: Within the limits of this ex vivo study, it was found that the manufacturing methods (M-wire or traditional NiTi) and kinematics (rotary or reciprocating motion) did not affect the shaping abilities of the systems. The extended file designs of highly tapered NiTi systems (ProTaper, WaveOne) resulted in greater deviations from the original root canal trace and more material removal when compared to less tapered systems (Sendoline S5, GT series X).

Efficacy of different irrigation techniques in the removal of calcium hydroxide from a simulated internal root resorption cavity.

AIM: To evaluate the efficacy of six irrigation techniques to remove calcium hydroxide (CH) from a simulated internal root resorption cavity. METHODOLOGY: The root canals of 100 single-rooted teeth were prepared using the ProTaper system to size F5. The roots were split longitudinally, and standardized simulated internal root resorption cavities were prepared in the two root halves. The root halves were reassembled, and CH was placed into the root canals, with the exception of five teeth that served as the negative control group. Another five teeth (the positive control group) were not subjected to the CH removal procedure. Ninety teeth were randomly divided into six experimental groups (n = 15), according to the final irrigation techniques used: conventional syringe irrigation (CSI), CanalBrush (CB), passive ultrasonic irrigation (PUI), self-adjusting file (SAF) system, EndoActivator (EA), and apical negative pressure irrigation (EndoVac system). Five millilitres of 3% NaOCl and 17% EDTA were used in all experimental groups during the CH removal procedure. The amount of remaining CH was evaluated under a stereomicroscope at 20 ×magnification, using a 4-grade scoring system. The data were statistically compared using the Kruskal-Wallis and Mann-Whitney U-tests (P < 0.05). RESULTS: Remnants of CH in simulated internal root resorption cavities were found in all experimental groups. SAF and PUI were superior to the other groups (P < 0.05); however, there was no significant difference between the SAF and PUI (P > 0.05). There were also no significant differences between the CSI, CB, EA and EndoVac groups (P > 0.05). CONCLUSIONS: None of the irrigation techniques was able to completely remove CH from a simulated internal root resorption cavity.

Could conscious sedation with midazolam for dental procedures be an alternative to general anesthesia?

AIM: The aim of our study was to evaluate the likelihood that conscious sedation (CS) with intravenous midazolam could become an alternative modality to general anesthesia (GA) for dental procedures. MATERIALS AND METHODS: In our study, 58 and 47 American Society of Anesthesiologists (ASA)-1 pediatric patients, aged 2-12 (mean 6) years, underwent dental procedures and minor oral surgical procedures under GA and CS with intravenous midazolam, respectively. The two groups were evaluated in terms of vital signs, duration of the treatment procedure, patient behavior, and the treatment comfort experienced by the physicians. RESULTS: The oxygen saturation level was significantly lower (GA: 99.0 ± 0.30, CS: 98.4 ± 1.02; P < 0.001) and the duration of the treatment procedure was significantly shorter (P < 0.001) in the sedation group compared with the GA group. The physicians encountered various difficulties during implementation of the treatment strategy in cases where they used CS. Minor oral surgical procedures and tooth extraction processes requiring no saline irrigation, however, could be performed successfully under CS. CONCLUSIONS: In cases requiring multiple dental management issues, the sedation method was not found to be a useful alternative to GA.

Efficacy of several techniques for the removal of calcium hydroxide medicament from root canals.

AIM: To compare the efficacy of several techniques for the removal of calcium hydroxide (Ca(OH)(2)) from root canals. METHODOLOGY: The root canals of 24 freshly extracted human mandibular premolars were prepared with ProTaper rotary instruments. The teeth were sectioned longitudinally along the length of the instrumented canals. The roots were subsequently reassembled with wires. After Ca(OH)(2) was placed into the canals, four techniques were used for its removal. In Group I, the teeth were irrigated with 5 mL of 2.5% NaOCl. Group II was treated in the same manner as Group I, but 5 mL of 17% EDTA was used in addition to NaOCl. In Group III, the teeth were irrigated with 5 mL of 2.5% NaOCl and agitated by an ultrasonic unit. In Group IV, the teeth were irrigated with 5 mL of 2.5% NaOCl and a CanalBrush was used to remove the Ca(OH)(2) . The roots were disassembled and digital photographs were taken. Measurements of residual Ca(OH)(2) were performed as percentages of the overall canal surface area. The data was analysed with one-way ANOVA with post hoc Tukey test. RESULTS: Significantly less residual material was obtained with a CanalBrush and passive ultrasonic agitation of NaOCl than the other groups (P < 0.05). There was no significant difference between syringe delivery of NaOCl and NaOCl+EDTA (P > 0.05). CONCLUSIONS: None of the techniques removed the Ca(OH)(2) dressing completely. CanalBrush and ultrasonic agitation of NaOCl were significantly more effective than irrigant-only techniques.