Push-out and Adaptability of a Novel Calcium Silicate Based Root Canal Sealer in Comparison with MTA Based Sealer : (in vitro study) /

Abstract

Successful endodontic treatment depends on the complete chemomechanical debridement, and 3D obturation of the canal space to prevent the bacterial ingress from the oral environment and its outspread to the periradicular tissues. The most crucial objective of this treatment is to eliminate the microbial entity and any possible future re-infection. Achieving this is by providing proper seal to diminish any chance of proliferation of microorganisms and occurrence of any pathology. Sealer combined with a solid obturating material acts in harmony to create this hermetic seal. Along time, endodontics has been going through enormous evolution where plenty of materials have been innovated. This reflects in the production of various types of root canal sealers; based on their composition, root canal sealers can be classified according to their composition as zinc oxide based sealers, sealers containing calcium hydroxide, glass ionomer based sealers, resin sealers, silicone based sealers, urethane methacrylate sealers, solvent based sealers, epoxy resin, methacrylate resin based sealers, and recently calcium silicate based sealers. The properties of ideal root canal sealers include being tacky when mixed to create good adhesion between it and the canal wall when set, to provide a tight seal. It should also be radiopaque so it can be radio-graphically visible. Moreover, its powder particles ought to be very fine to easily mix with the liquid, it must not shrink upon setting, nor must it stain the tooth structure, and it should not encourage bacterial growth. In addition to that, it should set slowly, be biocompatible, insoluble in tissue fluids, that is, and it should dissolve in a 1 Introduction common solvent to be able to remove it when needed. Another important property is that it should not provoke an immune response in periradicular tissues, and it should not be carcinogenic. The quality of the seal obtained with gutta-percha when used with conventional zinc oxide eugenol sealers was not very promising; it does not adhere to dentin, unable to control micro leakage, and the solubility of sealer makes prognosis very poor. However, new materials have been developed as alternatives that show better seal and mechanically strengthen compromised roots by achieving monoblocks, which has been claimed to decrease the ingress of bacterial pathways and reinforce the root to some extent. Among them are silicon-based sealers which are biocompatible, have low water sorption, and capable of forming monoblock, which reinforces the root canal. Epoxy resin–based sealers also have good of adhesion to the dentinal wall and with lower water solubility, and the breakthrough of mineral trioxide aggregate (MTA) -based sealers which have the tendency toward mineralization, along with all the viable properties of standard sealers. However, resin-based and silicon-based materials have shown to be also soluble, which may endanger a proper seal. Recently, bioceramics have been involved in the production of root canal sealers allowing, for the first time, to benefit from all its advantages and not limiting its use to merely roots repairs and apical retrofills. This is achieved due to the recent innovations in nanotechnology; the particle size of bioceramic sealer is so fine (less than two microns), it can be carried within a 0.012 capillary tip. This material has been introduced and considered as non-toxic calcium silicate cement that can be used as a root canal sealer in endodontics. Introduction The popularity of the use of bioceramics in the dental field, specifically endodontics is that bioceramics are very biocompatible, are not toxic, with no shrinkage –on the contrary it expands- upon setting, and are chemically stable within the biological environment. Also bioceramics will induce minimal, if any inflammatory response when overfilling occurs during obturation or in a root repair. Moreover, the material is able to form hydroxyapatite upon setting, and provide a strong bond between dentin and the filling material. The hydrophilic nature of the materials improves its adaptation to the canal wall. In essence, it is a bonded restoration, where the bond results from a hydration reaction that occur during the setting of this material; the calcium silicates in the powder hydrate to produce a calcium silicate hydrate gel and calcium hydroxide. The calcium hydroxide reacts with the phosphate ions to precipitate hydroxyapatite and water. The water continues to react with the calcium silicates to precipitate additional gel-like calcium silicate hydrate. The water supplied through this reaction is an important factor in controlling the hydration rate and the setting time. The mentioned reaction creates a bond between the sealer and the tooth structure, and forms adaption of this sealer on the dentin wall. Hence, these properties evoked the need to evaluate these sealers in this study.