Apical Extrusion of debris and cleaning Abilitiy using three Rotary Ni-Ti Sytems (An In Vitro Study)

Abstract

The root canal treatment procedure aims to remove any remaining infected pulp tissues or necrotic debris and infected dentin from within the canal spaces. The introduction of rotary NiTi instruments facilitated the effectiveness and speed of cleaning and shaping procedure even in most severe canal curvature resulting in the establishment of a better prognosis helping in restoring the lost function, through a 3 dimensional cleaning and shaping of the canals, together with a 3 dimensional sealing of the canal system. However, the complete removal of the microorganisms from within the canals is considered somehow difficult with the use of mechanical shaping only. As this mechanical shaping instruments will result in the production of a considerable amount of debris, and a tenaciously adherent amorphous structure known as the smear layer. This layer contains bacteria and their byproducts and particles of collagen matrix, compromising the final outcome of the treatment by creating flaws in the obturation. These flaws result from several factors that happened due to the incomplete removal of the previously mentioned debris and smear layer caused by the mechanical cutting of the infected dentin within the canal during the treatment process. These factors result from the inability of the irrigating materials and the intracanal medicaments to penetrate through the dentinal tubules and deeply clean and disinfect the surface and this is caused by the incomplete removal of the smear layer. The smear layer also compromises the bonding and the penetration of the sealers to the dentinal walls causing further percolation of fluids from the inflamed periapical tissues compromising the apical and the coronal seal, resulting in failure of the treatment. The present study was designed to evaluate the amount of extruded debris and the cleaning ability after using different three full sequence rotary systems.