ABSTRACT
CONTEXT: Canal shaping abilities such as canal transportation, centering ability, and preparation time are important and have to be considered before using any Nickel-Titanium file system. AIM: This in vitro study aimed to evaluate and compare the amount of canal transportation, centering ability, and time required for the shaping of severely curved canals with WaveOne Gold (WOG) Primary Reciprocating file and One Curve (OC) Rotary file using the micro computed tomography (µCT). MATERIALS AND METHODS: Thirty intact mesial roots of extracted human mandibular first molars having severe curvature (25°-35°) were selected. Samples were divided into two groups. Samples in Group I and II were shaped with WOG primary reciprocating files and OC rotary files, respectively, to the working length. Time required to prepare each canal was recorded. µCT pre- and post-instrumentation scans of all samples were taken. The cross-sectional images at 3, 6, and 9 mm from the radiographic apex were selected for analysis. Statistical analysis was performed using the Kruskal-Wallis and unpaired t-test. RESULTS: At 3 mm, OC showed statistically lower canal transportation with mean value (0.17 ± 0.10) than WOG (0.55 ± 0.42). Furthermore, OC showed statistically significant better centering ability (0.59 ± 0.25) than WOG (0.39 ± 0.20) at 3 mm level. However, the differences between both instruments were not statistical significant at 6 and 9 mm level for canal transportation and centering ratio. WOG reciprocating file required less time for canal preparation than OC file. CONCLUSIONS: OC rotary file showed less canal transportation and better canal centring ability than WOG file, during the preparation of severely curved canals. However, WOG required less time for canal preparation.
ABSTRACT
OBJECTIVE: The aim of this study was to comparatively evaluate in vivo the disinfecting ability of conventional method and lasers in root canals. MATERIALS AND METHODS: Study criteria included 60 single rooted teeth, which were indicated for root canal therapy followed to dental caries and trauma with intact crowns. Such selected patients were randomly divided into 2 groups, namely, Group A (30 teeth) and Group B (30 teeth). All clinical procedures were carried out under strict aseptic precautions. The teeth in Group A were subjected to biomechanical preparation followed by the treatment with the help of diode laser containing the gallium aluminum and arsenic, which emitted 980 nm wavelengths. The teeth in Group B were treated with routine method of biomechanical preparation along with irrigation using sodium hypochlorite and hydrogen peroxide. The microbiological samples were taken immediately after the access preparation and after the completion of the root canal disinfection and were sent for microbiological analysis. RESULTS: The teeth in Group A showed presence of common strains of bacteria ranging from Streptococci, Staphylococci, Klebsiella, and Pseudomonas. Reduction in the growth of microorganisms was found for all types of microorganisms. Only 8 samples exhibited the growth after treatment with laser. Results of Group B also showed the presence of common strains of anaerobic and aerobic bacteria as shown in earlier studies, predominantly Staphylococcus, Streptococci, and Pseudomonas. Statistical analysis showed non-significant P values for the microorganisms; however, only 3 samples showed the growth after treatment with conventional technique using sodium hypochlorite and hydrogen peroxide. CONCLUSION: Conventional method by using sodium hypochlorite and hydrogen peroxide as irrigating solutions is highly effective in disinfecting the root canal. Lasers when used can also reduce the bacterial load of the infected root canal.
