Richard E. Rutledge

In Vitro Comparisons of Debris Removal of the EndoActivatorTM System, the F FileTM, Ultrasonic Irrigation, and NaOCl Irrigation Alone after Hand-rotary Instrumentation in Human Mandibular Molars

INTRODUCTION The purpose of this in vitro study was to compare the debris removal efficacy of the EndoActivator system, the F file, ultrasonic irrigation, or 6% NaOCl irrigation alone in human mandibular molars after hand-rotary instrumentation. METHODS A custom brass cube (K-Kube) was used to create a sealed canal system, allowing each tooth to serve as its own control. Forty extracted mandibular molars were randomly divided into 4 equal experimental groups. Each tooth was mounted, sectioned at 1, 3, and 5 mm from the working length, and then reassembled into the K-Kube, and the mesial roots were similarly prepared by using hand-rotary instrumentation. For final debridement, group 1 used F file for 30 seconds, group 2 used EndoActivator system for 30 seconds, group 3 used ultrasonic irrigation for 30 seconds, and group 4 used irrigation with 6% NaOCl within 1 mm of working length. All groups received a final irrigation with 6% NaOCl in each canal. Specimens were evaluated at 1, 3, and 5 mm from the working length for cleanliness by capturing a digital image with a stereomicroscope. All specimens had the percent cleanliness for each canal and isthmus calculated both before and after final debridement. Statistical analysis was completed by using a repeated-measures analysis of variance with Tukey post hoc tests. RESULTS AND CONCLUSIONS The results showed no statistically significant difference in canal or isthmus cleanliness among the 4 groups, but there was a statistically significant difference (P < .001) in canal cleanliness between the 1-mm level versus the 3-mm and 5-mm levels for all of the groups.

Comparison of Debris Removal with Three Different Irrigation Techniques

INTRODUCTION The purpose of this study was to compare the effectiveness of debris removal between EndoVac, PiezoFlow, or needle irrigation (Max-i-Probe) in mandibular molars. METHODS The mesial roots of 30 extracted mandibular molars were mounted in resin by using the K-Kube and then sectioned at 2 and 4 mm from the apex. The specimens were reassembled and instrumented to size 40/0.04. A standard irrigation protocol was used during instrumentation in the PiezoFlow and Max-i-Probe groups. During instrumentation of teeth in the EndoVac group, the manufacturers recommendations for irrigation were followed. Images of the canals and isthmuses were taken before final irrigation. The percentage of cleanliness for each canal and isthmus was calculated by using interactive software. The specimens were reassembled for final irrigation with EndoVac, PiezoFlow, and Max-i-Probe by using similar volumes of irrigants. Images were again used to calculate cleanliness. Comparisons of canal and isthmus cleanliness before and after final irrigation were made by using paired t tests, and the groups were compared with repeated-measures analysis of variance (P < .05). RESULTS There were no statistically significant differences in canal and isthmus cleanliness among all 3 groups at 2 and 4 mm from working length before or after final irrigation. Canal and isthmus cleanliness significantly improved at all levels after the final irrigation regimen in each group. CONCLUSIONS Final irrigation by using EndoVac, the PiezoFlow, or Max-i-Probe with similar volumes of irrigants significantly improved canal and isthmus cleanliness.

An alternative to apexification

Because of time constraints, financial concerns, psychological status, or aesthetic demands of the patient there are times when traditional apexification can not be performed. This case report describes an alternative technique using calcium hydroxide powder to develop an apical barrier in a pulpless tooth. This technique is an easy and efficient method requiring only a single visit to develop an apical stop to facilitate dense obturation.

Reinforcement of Simulated Immature Roots Restored with Composite Resin, Mineral Trioxide Aggregate, Gutta-percha, or a Fiber Post after Thermocycling

INTRODUCTION The purpose of this study was to evaluate the fracture resistance after thermocycling of simulated immature teeth restored with composite, a fiber post, mineral trioxide aggregate (MTA), or gutta-percha. METHODS Eighty-four primary bovine mandibular incisors were divided into 7 groups (n = 12). Negative controls received no treatment. Teeth in all other groups were prepared to an internal diameter of 1.75 mm. After placement of 4-mm apical barrier of MTA, the canals were filled with their respective test materials to the facial cementoenamel junction. For the fiber post group, a fiber post was fitted to extend from the MTA barrier to 2 mm below the incisal edge and was cemented with Build-It FR. The positive controls were left unfilled. The access openings were filled with BisFil II composite. All teeth were then thermocycled for 500 cycles at 5 °C and 55 °C with a 30-second dwell time and 5-second transfer time. Each root was horizontally fractured through the test material by using an Instron Universal Testing Machine, and the peak load to fracture was recorded. The data were analyzed with analysis of variance and Tukey post hoc tests (P < .05). RESULTS AND CONCLUSIONS Thermocycled composite was not significantly stronger than gutta-percha and MTA. The only material that significantly strengthened the simulated immature teeth was the fiber-reinforced composite with a fiber post.

Comparison of Nonsurgical Root Canal Treatment and Single-tooth Implants

INTRODUCTION The aim of this review was to compare the differences between nonsurgical root canal treatment and single-tooth implants. With the emerging field of implant dentistry gaining acceptance, the choice to retain a diseased tooth through the use of root canal therapy or extract it and replace the tooth with an implant-supported crown has become controversial. Many practitioners consider the single-tooth implant as a reasonable alternative to the preservation of a diseased tooth. METHODS An extensive search of the dental literature was accomplished to identify publications related to the differences in root canal therapy and dental implants. Several comparative studies were also considered. RESULTS The treatment modalities were reviewed with respect to outcome measures and study design, success/failure, functional rehabilitation and psychological differences, complications related to treatment, cost differences, and factors influencing treatment planning considerations. CONCLUSIONS With the reviewed information in hand, the practitioner should be better prepared to determine which treatment option is most appropriate for each individual patient.

Cyclic fatigue resistance of two variable-taper rotary file systems: ProTaper universal and V-Taper.

The cyclic fatigue resistance of ProTaper Universal (Dentsply Tulsa Dental Specialties, Tulsa, OK) and V-Taper (Guidance Endo, Albuquerque, NM) files was measured while rotating files around a 5-mm radius curve with 90 degrees of maximum flexure. The files were rotated at 250 rpm with a continuous axial oscillation of 4 mm at 1 Hz. The number of cycles to failure was calculated and analyzed by using univariate analysis of variance and the Tukey HSD posthoc test with results confirmed by nonparametric Kruskal-Wallis and Mann-Whitney U tests with a Bonferroni correction. The fracture faces of representative files were imaged with a scanning electron microscope to confirm cyclic fatigue as the mode of fracture. For the instruments tested, the ProTaper files appeared to resist fracture better than the V-Taper files. At each tip size tested, the ProTaper files either outperformed or were not statistically different than V-Taper files.

Effect of intracanal medicaments on the sealing ability of TERM

An in vitro leakage study was performed to determine the effect of intracanal medicaments on the sealing ability of Temporary Endodontic Restorative Material (TERM). Fifty extracted mandibular molars with uniform access preparations were restored with TERM after placement of either a dry cotton pellet (control) or a pellet moistened with eugenol, formocresol, CMCP, or a paste of sodium perborate and superoxol. Multiple quantitative measurements were made on each intact specimen at five time intervals after restoration, and, in some cases, after thermocycling. Statistical analysis revealed no significant leakage in the control group, or in the groups which used eugenol, formocresol, or CMCP when they were compared with the control group. Analysis, however, did show significant leakage for the group containing the bleaching paste. The authors concluded that the sealing ability of TERM is not affected by eugenol, formocresol, or CMCP. However, it should not be used for the temporary restoration of teeth being treated by the walking bleach technique.

pH changes in external root surface cavities after calcium hydroxide is placed at 1, 3 and 5 mm short of the radiographic apex

The purpose of this study was to test the null hypothesis that there is no difference in the pH on the external apical dentin surface when the canal is completely filled with calcium hydroxide or when it is placed 3 or 5 mm short of the apical foramen in extracted human teeth. The root canals of single-rooted anterior human teeth were cleaned and shaped after decoronation. Cavities about 0.50 mm deep and 1.0 mm wide located at 1, 3 and 5 mm from the radiographic apex were prepared on the external root surface and the teeth were randomly divided into four groups. The roots were filled with calcium hydroxide at 1, 3 and 5 mm from the radiographic apex, and the control group was left empty. pH readings were obtained at intervals over a 28-day study. The roots which were filled within 1 mm of the radiographic apex had the greatest increase in pH in each of the cavities. These results demonstrate that the greatest pH change on the external root surface near the apex is obtained when the canal is more completely filled with calcium hydroxide.