The effect of the quality of removal of temporary sealers from anatomically limited volumes of the root canal system on the quality of root canal obturation

Abstract

The success of endodontic treatment depends on many factors. One of the most important is the proper root canal obturation. In the treatment of apical periodontitis, temporary sealers are used to improve healing process of the infected periodontium, which contain calcium hydroxide on different bases: hydrophilic and hydrophobic. If there are remnants of temporary sealants, the doctor cannot guarantee the good root canal obturation. Complete removal of temporary sealers from the root canal system and dentine tubules is ensured by the use of special irrigants. The aim. Evaluate the application of adhesion of epoxy resin sealant after temporary root canal filling.Materials and methods. Samples of 60 intact molars were randomly distributed into six groups. In the samples of the 1st group, a sealant based on epoxy resins was used; In the 2nd group, before applying the sealer, dentin samples were additionally treated with liquid for drying and degreasing the hard tissues of the tooth. In the samples of teeth in the 3rd and 4th group, a paste with calcium hydroxide on a hydrophilic basis with calcium hydroxide was applied to the dentin section. Then epoxy sealer was used for permanent obturation. In the samples of teeth in the 4th group, dentin was applied liquid for drying and degreasing the hard tissues of the tooth before the use of epoxy sealer. In the samples of teeth in the 5th and 6th groups, a hydrophobic paste containing calcium hydroxide and silicone-based iodoforms was applied to the dentin section before the application of epoxy sealer. In the samples in the 6th group, dentin was pretreated with liquid for drying and degreasing the hard tissues of the tooth. In the samples of all groups, the adhesive shear strength was determined on the test machine «SYNTHEZ 5» (France). After the tests, the samples were studied by scanning electron microscopy (SEM).The resultsof the study showed adhesive shear strength in the 1st group of (9,1±1,2) MPa, in the 2nd group – (11,4±1,1) MPa, in the 3rd group – (8,0±1,1) MPa, in the 4th group – (10,5±1,1) MPa, in the 5th and 6th groups – (7,6±1,3) MPa and (10,3±1,1) MPa, respectively. Samples treated with a liquid for drying and degreasing the hard tissues of the tooth under SEM showed the penetration of epoxy sealer into the dentin tubules.Conclusion. The adhesive strength of the epoxy resin-based sealant after the application of pastes for temporary filling of root canals ranges from (9,1±1,2) МРа до (11,4±1,1) MРa. Residual fragments of pastes on hydrophilic and hydrophobic bases reduce the strength of adhesion of the root sealаnt to dentin.The use of liquid for drying and degreasing the hard tissues of the tooth allows to remove the remnants of the paste from the root canal as much as possible and increases the strength of adhesion of the root sealant to the dentin.