Comparative Analysis of the Cleaning Ability and Surface Topography of One Shape Single File versus Protaper Universal Files : An In Vitro Study /

Abstract

Biomechanical preparation, disinfection and obturation all together constitute equally important phases of the endodontic treatment. A successful outcome of root canal treatment depends on several factors such as, adequate cleaning of the root canal by removing infected and necrotic pulp remnants, elimination of microorganisms, complete removal of debris and smear layer to produce a perfect seal between the filling material and the root dentin, which is important on the outcome of the root canal treatment. Smear layer and debris may be one of the common causes of root canal treatment failure. Debris contains vital and/or necrotic pulp tissue and dentinal chips that loosely attach to the root canal walls, it is usually infected. The smear layer consists of dentine particles, remnants of vital or necrotic pulp tissues, bacterial components, and retained irrigants. The smear layer is reported to prevent the penetration of irrigating solutions, medications and filling materials into dentinal tubules, thus affecting the outcome of the root canal treatment. The basic design of root canal instruments has changed very little over the years, apart from the minor modifications such as new materials, improved cutting edges and greater flexibility. One of the many innovations in root canal instruments is the use of nickel titanium for file manufacture, which have two to three times more elastic flexibility than stainless steel files and appear to be more fracture resistant compound to stainless steel files. During last decade several new Ni-Ti instruments for manual root canal preparation, as well as for use in rotary endodontic hand pieces have been developed, in order to facilitate the difficult and time consuming 1 Introduction process of cleaning and shaping the root canal system and to improve the final quality of root canal preparation. From these new rotary files are ProTaper Universal files and One Shape file which may help in removal of smear layer during endodontic treatment and thus increasing the quality of root canal treatment outcome. After using these NiTi instruments a several defects may appear on the surface of these files. These defects may lead to the fracture of the endodontic file during the cleaning and shaping of the root canal, which may lead to the failure of the root canal treatment. So it is important to have the knowledge about these defects in order to prevent the fracture of the endodontic file while usage that may lead to the failure of the treatment. Introduction of scanning electron microscope (SEM) has proved to be valuable method for assessment of the ability of the endodontic procedures to remove debris from root canals thus enabling comparison of instruments and techniques, and also using SEM in the assessment of the defects appears in the files after usage.