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Aims: The aim of this study was to evaluate the number of intracanal bacteria extruded apically during root canal preparation using rotary ProTaper, K3XF, twisted, and hand K‑file system. Subjects and Methods: Seventy extracted single‑rooted human mandibular premolar teeth were used. Access cavities were prepared and the teeth were mounted in glass vials. Root canals were then contaminated with a pure culture of Enterococcus faecalis (ATCC 29212) and incubated at 37°C for 24 h. The contaminated roots were divided into four experimental groups of 15 teeth each and one control group of 10 teeth. Group 1: ProTaper; Group 2: K3XF; Group 3: Twisted file; Group 4: Hand K‑file; Group 5: Control group. Bacteria extruded from the apical foramen during instrumentation were collected into vials. The microbiological samples were incubated in culture media for 24 h. Colonies of bacteria were counted and the results were given as number of colony‑forming units (CFU)/ml. Statistical Analysis Used: The obtained data were analyzed using the Kruskal–Wallis one‑way analysis of variance and Mann–Whitney U‑tests. Results: There was a significant difference between the rotary and hand instrumentation system related to the apically extruded intracanal bacteria. Conclusions: Both the rotary and hand instrumentation systems extruded intracanal bacteria through the apical foramen. K3XF file system showed least bacterial extrusion amongst all instrumentation groups.
ABSTRACT
Objective To evaluate the influence of ProTaper rotary nickel-titanium files root preparation on root canal filling . Methods 30 cases of molars pulpitis and 20 cases of premolars pulpitis or periapical periodontitis were equally divided into two groups .The group A(30 cases) used the ProTaper rotary nickel-titanium files in root canal preparation and the group B (30 cases) adopted the common K files modified step-back technique for root canal preparation .The influence of the root preparation by 2 sets of apparatus on the effect of root canal filling ,and the several aspects of the root canal filling time ,the matching degree of main root canal file and master gutta-percha ,proper filling rate ,postoperative reaction of root canal filling were compared for conducting the e-valuation .Results In the mean root canal filling time of the group A ,average premolar time was 4 min 25 s and molar was 1 min 30 s ,however in the group B ,average premolar was 5 min 30 s and molar was 11 min 41 s ,the time in the group A was greatly short-ened with statistical difference(P0 .05);the postoperative pain reaction of root canal filling in both groups were very low and weak without statistical difference .Conclusion The ProTaper rotary nickel-titanium files root preparation can accelerate the root canal filling speed ,improve the matching degree of main root canal files and master gutta-percha and simplify the root-filling therapy procedure .
ABSTRACT
OBJECTIVES: The purpose of this study was to determine the optimal master apical file size with minimal transportation and optimal efficiency in removing infected dentin. We evaluated the transportation of the canal center and the change in untouched areas after sequential preparation with a #25 to #40 file using 3 different instruments: stainless steel K-type (SS K-file) hand file, ProFile and LightSpeed using microcomputed tomography (MCT). MATERIALS AND METHODS: Thirty extracted human mandibular molars with separated orifices and apical foramens on mesial canals were used. Teeth were randomly divided into three groups: SS K-file, Profile, LightSpeed and the root canals were instrumented using corresponding instruments from #20 to #40. All teeth were scanned with MCT before and after instrumentation. Cross section images were used to evaluate canal transportation and untouched area at 1- , 2- , 3- , and 5- mm level from the apex. Data were statistically analyzed according to' repeated nested design'and Mann-Whitney test (p = 0.05). RESULTS: In SS K-file group, canal transportation was significantly increased over #30 instrument. In the ProFile group, canal transportation was significantly increased after preparation with the #40 instrument at the 1- and 2- mm levels. LightSpeed group showed better centering ability than ProFile group after preparation with the #40 instrument at the 1 and 2 mm levels. CONCLUSIONS: SS K-file, Profile, and LightSpeed showed differences in the degree of apical transportation depending on the size of the master apical file.
Subject(s)
Humans , Dental Pulp Cavity , Dentin , Hand , Molar , Nickel , Stainless Steel , Titanium , Tooth , Tooth Apex , Transportation , X-Ray MicrotomographyABSTRACT
The aim of this study was to compare the effects of anticurvature filing with stainless steel k-file versus nickel-titanium ProFile in the shaping of mesial root canals of extracted mandibular molars. A total of 60 canals from 30 mesial roots of mandibular molar teeth were randomly assigned to three groups with n=20 each. They were prepared with different instruments and methods: The first group with stainless steel k-file and circumferential filing, the second with precurved stainless steel k-file and anticurvature filing and the third with ProFile (.06 taper) and anticurvature filing. Using a micro-computed tomography system (skyscan-1076, SKYSCAN, Antwerpen, Belgium), pre-and post-operative specimens were scanned. Subsequently, canal images were superimposed and changes in root dentin thickness were measured at distal side (danger zone) of the canal. The data was analyzed using a one-way ANOVA and the comparison of means was conducted using a post hoc multiple comparison Tukey test. There were significant differences in the change of root dentin thickness at the 7.5~8.5mm level between group 1 and 2, 3.5~6mm level between group 1 and 3 and 3.5~6mm level between group 2 and 3(n=20, P<0.05).
Subject(s)
Dental Pulp Cavity , Dentin , Molar , Stainless Steel , ToothABSTRACT
The aim of this study was to evaluate the effectiveness of sealer placement in simulated root canal extensions. Forty resin blocks were attained from the Endo-training Bloc. In each block, the simulated root canal was made with #20, 08taper GT file. After each block was longitudinally split into two halves, a standardized groove was prepared on one canal wall of two halves to simulate the canal extensions with various irregularities. The two halves of each block were assembled and all simulated root canals were obturated by single cone method with AH26 sealer. Four different methods of sealer placement were used: group A, #20 K-file; group B, ultrasonic file; group C, lentulo spiral; group D, EZ-Fill bi-directional spiral. All obturated blocks were stored in 100% humidity at 37degrees C for 1 week. Using a low speed saw, each block was sectioned horizontally. Images of the sections were taken using a stereomicroscope at x 30 magnification and a digital camera. The amount of the sealer in the groove was evaluated using a scoring system, a higher score indicated better sealing effectiveness. The data was statistically analysed by Fisher's Exact Test. The sealing score was the lowest, specially at the middle area of canal extensions in group A, and that was statistically significant difference from other groups. In conclusion, the ultrasonic file, lentulo spiral and EZ-Fill bi-directional spiral were effective methods of sealer placement in simulated canal extensions. The K file was the least effective method, specially at the middle area of canal extensions.