Smear layer removal and canal cleanliness using different irrigation systems

The percentage of failures and the will to establish more practical protocols specifically in the field of endodontics have led, over the years, to the continuous development of new techniques to be able to make more predictable all types of endodontic treatment. Advances in this area are the result of a long process that began in the seventeenth century and that still goes on. The purpose of endodontic treatment is now clearly established, but it changes the path that allows dentists to achieve certain goals. The need to resort to an intervention of endodontic therapy is motivated by the presence of pulpal disease, the cause of which is to be found in bacterial growth within the endodontic complex. The three basic stages of endodontic treatment are represented by a diagnostic phase, a preparatory phase, during which, through the cleansing and shaping of the canal, removing the root canal content, the disinfection of the endodontic complex is performed and it is given to the same canal a three-dimensional shape adapted to receive a filling, and finally the obturation phase, during which the canal is clogged with an inert material, capable of ensuring a complete seal of the endodontic complex. Although it is impossible to determine which of the three stages is the most decisive, it is obvious that great importance should be attributed to the cleansing, disinfection and shaping. There is talk of cleansing and shaping because when a root canal system is prepared it is actually cleaned from all organic and inorganic debris, and from all microorganisms, and it is shaped to give a form which facilitates the execution of a correct three-dimensional obturation. The purpose of the cleansing is to remove from the inside of the root canal system the intracanal material, be it of pulpal origin or micro-organisms. The first phase of the endodontic therapy is the correct opening of the pulp chamber that allows a correct access to all the channels present inside the endodontic complex. The second objective of the first stage of endodontic therapy is the survey of the channels and their morpho-structural anatomical analysis. It then begins a phase of shaping and cleaning of the endodontic complex act to remove the organic and inorganic materials that may prevent proper decontamination and cleansing endodontic. Regardless of the shaping technique and the tools used to perform it, it is of fundamental importance to use the root canal irrigant. It 'also shown that there are two important conditions to ensure that the cleansing has maximum effectiveness, ie its residence time inside the endodontic complex and its activation. Different agitation and delivering techniques were suggested. Passive ultrasonic irrigation (PUI), firstly described by Weller et al, uses a stainless steel file to activate the irrigant in the canal. PUI is able to disrupt the endodontic biofilm, facilitating better penetration of irrigants throughout the endodontic dentinal walls. The EndoActivator System (EA) (Dentsply Tulsa Dental Specialties, Tulsa, OK) is a sonically driven irrigant activation system designed to produce vigorous intracanal fluid agitation that has been shown to increase the efficacy of irrigation better than traditional needle irrigation (18). The EndoVac System (EV) (Discus Dental, Culver City, CA) is an apical negative pressure irrigation device designed to drain irrigating solution at the apical third level of the canal system and to remove debris via a negative pressure mechanism. Lasers were introdued as an alternative to irrigant activating methods, able to clean and disinfect root canals. Different lasers at different wavelengths were investigated in an attempt to develop improved treatment methods. Laser activated irrigation (LAI) with erbium lasers was studied as a method to activate irrigating solutions. The aim of my PhD was based on the evaluation of smear layer removal and endodontic wall cleanliness after different irrigant activation regimens, studying and analyzing one by one its materials, techniques and results