Chemical aspects of the dental adhesives.A literature Review

Adhesive dentistry has undergone significant progress in the last decades.The purpose of this article is to review the literature on the current knowledge of each adhesive system according to their classification.The article emphasises the evolution of dental adhesives and the chemical interaction between their components, the collagen matrix, and hydroxyapatite crystals of the hard dental tissues.It describes the basic strategies of adhesion.The development of adhesives and techniques is a long story.The first generations have low bond strength to the dentin.The third-generation dentin adhesive has better, but not sufficient bond strength.The fourth generation (total-etch) dentin adhesives represent great progress in the dentin adhesives.The evolution of the dentin adhesive continues by simplifying the adhesive protocol (5th -generation), and after that, it is searching for a new strategy for adhesion (6th, 7th and 8th generations self-etching systems).