Evaluation of reduction in intracanal bacteria by three instrumentation technique: K-type manual system file, rotary race and profile system

Root canal cleaning and elimination of the source of infection are the most important basis and the main requirements for successful root treatment since the main cause of failure in root treatment is the permeation of bacteria or their products into the periapical tissues. Nowadays, the newly designed and prcsented instruments for canal instrumentation can improve root treatment. The aim of this study was to compare the decrease in the number of intracanal Enterococcus-faecalis [Ef] among three mechanical instrumentation methods: manual [K-type] and rotary [Race, Profile]. In this experimental study, 30 single rooted teeth were selected. Three cases were considered as negative and three cases as posetive controls and 24 remainder cases were divided into three experimental groups. All root canals were inoculated by Ef and samples were taken from all canals to prepare microbial cultures. The three instrumentation procedures were: - Crown- down technique with K-type manual system file - Crown- down technique with Profile rotary system - Crown- down technique wiht Race rotary system After instrumentation, microbial cultures were taken from root canals and the reduction rate of bacteria were evaluated and compared using one way ANOVA test with P<0.05 as the limit of significance. There was no significant difference among the three instrumentation procedures regarding bacterial elimination. According to the finding of this study, K-type manual file, Profile and Race rotary systems, all can be used in canal instrumentaion. However, since manual files are more accessible and require less equipment compared with rotary systems, and since the ability of all of these methods is identical regarding bacterial elimination, manual files can be used in straight canal instead of rotary systems

histologic evaluation on tissue reaction to three implanted materials [MTA, root MTA and Portland cement Type I] in the mandible of cats

Statement of Problem: Nowadays Mineral Trioxide aggregate [MTA] is widely used for root end fillings, pulp capping, perforation repair and other endodontic treatments. Investigations have shown similar physical and chemical properties for Portland cement and Root MTA with those described for MTA

Purpose: The aim of this in vitro study was to evaluate the tissue reaction to implanted MTA, Portland cement and Root MTA in the mandible of cats

Materials and Methods: Under asepsis condition and general anesthesia, a mucoperiosteal flap, following the application of local anesthesia, was elevated to expose mandibular symphysis. Two small holes in both sides of mandible were drilled. MTA, Portland cement and Root MTA were mixed according to the manufacturers, recommendation and placed in bony cavities. In positive control group, the test material was Zinc oxide powder plus tricresoformalin. In negative control group, the bony cavities were left untreated. After 3, 6 and 12 weeks, the animals were sacrificed and the mandibular sections were prepared for histologic examination under light microscope. The presence and thickness of inflammation, presence of fibrosis capsule, the severity of fibrosis and bone formation were investigated. The data were submitted to Exact Fisher test, chi square test and Kruskal Wallis test for statistical analysis

Results: No statistically significant differences were found in the degree of inflammation, presence of fibrotic capsule, severity of fibrosis and inflammation thickness between Root MTA, Portland cement and MTA [P>0.05]. There was no statistical difference in bone formation between MTA and Portland cement [P>0.05]. However, bone formation was not found in any of the Root MTA specimens and the observed tissue was exclusively of fibrosis type

Conclusion: The physical and histological results observed with MTA are similar to those of Root MTA and Portland cement. Additionally, all of these three materials are biocompatible. However, in order to replace Root MTA and Portland cement type I as less expensive and suitable substitutes for MTA, more longer- term studies with larger number of samples are suggested