Evaluation of the dentin remaining after flaring using Gates Glidden drills and Protaper rotary files

INTRODUCTION: The application of rotary instruments for root canal preparation requires a safe, not harming procedure to the root structure remaining. OBJECTIVES: The purpose of this study was to analyze the root thickness in 28 mesial canals of lower permanent first molars before and after flaring using two rotary instruments: Gates-Glidden drills and ProTaper rotary files. MATERIAL AND METHODS: Teeth were embedded into a muffle system. Samples were obtained by cutting 2mm below the furcation. The images were captured by a digital video system (8X and 12X magnification). For image analysis and processing, Pro-Image Plus 4.1 software was used. Each image captured by the computer was gauged, eliminating any possible distortion. Gates-Glidden drills were used in decreasing order of size (GG#4, GG#3, GG#2). ProTaper was used according to the manufacturer's recommendations, with hand-piece powered by an electric motor with low torque. 5.25 percent sodium hypochlorite was utilized as irrigant. RESULTS: The average thickness between the canal and furcation before and after use of rotary instruments were: 0.857 mm and 0.561 mm for Gates-Glidden drills, and 0.858 mm and 0.486 mm for ProTaper, respectively. No statistical differences were found in the root thickness of specimens shaped with ProTaper rotary files and Gates Glidden drills. CONCLUSION: The use of Gates-Glidden drills is as safe as ProTaper rotary files with respect to danger of perforation on the distal side of the mesial roots of lower molars.

Filling lateral canals: evaluation of different filling techniques.

OBJECTIVES: The purpose of this in vitro quantitative laboratorial study is to compare the ability of three filling techniques to fill simulated lateral canals. METHODS: Thirty extracted, single-rooted human teeth were used. After cleaning and shaping, three lateral canals were created, one in each third. The teeth were randomly separated into three groups: continuous wave of condensation (Group 1); thermomechanical compaction (Group 2); and lateral condensation (Group 3). The teeth were cross-sectioned, making the cut through points over the lateral canals; thus, 90 specimens were obtained. Each specimen was immersed in a polyester resin, and the blocks were polished. Images were obtained using a stereoscopic lens (40x). Radiographic analysis was performed, followed by a filling linear measure using the Image Tool 3.0 program (University of Texas). Data were statistically analyzed using SPSS 12.0 for Windows (Kruskal-Wallis test). RESULTS: A greater number of simulated lateral canals were obturated in Groups 1 and 2. Group 2 presented the largest percentage of linear measure of lateral canals filling with gutta-percha and sealer. No statistical differences were found between Group 1 and Group 2 when we analyzed the filling with gutta-percha and sealer or just sealer (P>.05). CONCLUSIONS: Thermoplasticized gutta-percha filling techniques (Groups 1 and 2) are better for filling lateral canal with gutta-percha and sealer or with just sealer than lateral condensation (Group 3).

Ex vivo evaluation of coronal and apical microbial leakage of root canal--filled with gutta-percha or Resilon/Epiphany root canal filling material.

OBJECTIVE: This ex vivo study compared coronal and apical microleakage of root canals filled with Resilon/Epiphany (RE) or gutta-percha/Grossman sealer (GP), using either lateral condensation (LC) or System B (SB) technique. MATERIALS AND METHODS: Specimens in eight experimental groups were obturated using the following materials and techniques: Groups 1 and 3--GP and LC; groups 2 and 4--GP and SB; groups 5 and 7--RE and LC; groups 6 and 8--RE and SB. Apical and coronal leakages were tested using bacterial methods. For coronal analysis, the number of days required for complete contamination of the root canals was recorded according to observation of the brain heart infusion broth turbidity for 15 weeks. For apical analysis, the teeth were cleaved and the leakage was measured at 30 days. Data were collected for each sample and analyzed statistically with the Chi-square and ANOVA tests. RESULTS: Leakage was found in all groups. The difference between filling materials, obturation techniques, and median time of leakage was not statistically significant for coronal ( P=0.847) and apical ( P=0.5789) leakages. CONCLUSION: There were no differences between the different filling materials (gutta-percha/Grossman sealer and Resilon/Epiphany) and obturation techniques (lateral condensation and system B technique) in coronal or apical leakages.

Clinical evaluation of the use of three anesthetics in endodontics.

This study compared three anesthetics widely used in endodontics and analyzed the following variables: amount necessary to achieve adequate anesthesia; anesthetic efficacy, defined as no sensation during endodontic treatment; anesthetic duration; and cost-benefit. Sixty patients diagnosed with irreversible pulpitis of a mandibular molar were selected at the Dental Emergency Center of Universidade de Fortaleza, Brazil. Patients were randomly divided into three groups of 20 and were administered one of three anesthetic solutions for conventional regional block: 2% lidocaine with 1:2500 phenylephrine; 2% mepivacaine with 1:100,000 adrenaline and 4% articaine with 1:100,000 epinephrine. The following variables were studied: number of cartridges necessary to obtain anesthetic success; anesthetic efficacy, defined as no sensation during endodontic procedures; anesthetic duration; cost-benefit ratio for each anesthetic. Mean number of cartridges necessary to obtain anesthetic success was 2.76, and there was no statistically significant difference between the anesthetics used. Lidocaine had the best cost-benefit ratio. All anesthetics used were clinically efficient and had equivalent results for endodontic treatment.