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Adhezijski sustavi posreduju u vezanju kompozitnih materijala na tvrda zubna tkiva. Sastavljeni su od primera odnosno temeljnog premaza koji sadrži monomere hidrofilnih svojstava te bonda ili završnog premaza koji sadrži hidrofobnu smolu koja se polimerizira. Prije njihove primjene obvezna je priprema površine tvrdih zubnih tkiva aplikacijom kiseline koju nazivamo jetkanjem. Njihova primjena temelji se na adheziji koju definiramo kao spajanje dvaju različitih materijala privlačenjem atoma i molekula. Osnovni princip adhezije je uklanjanje minerala tvrdih zubnih tkiva jetkanjem i njihova izmjena s monomerom koji se mikromehanički veže u novonastalim porama. Ona se različito ostvaruje u caklini i dentinu s obzirom na njihove razlike u građi i reakciji na jetkanje. Adhezivi se mikromehanički uklješćuju u jetkane pore na caklinskim prizmama, dok u dentinske kanaliće difundiraju te inflitriraju ogoljela kolagena vlakna stvarajući i kemijsku vezu. Koncept adhezijskih sustava počinje se razvijati 1955. godine zaslugom Michaela G. Buonocorea koji koristi fosfornu kiselinu za pripremu površine cakline prije aplikacije polimetil-metakrilatne smole. Vrlo važnim događajem u razvoju adhezijskih sustava smatra se i definicija hibridnog sloja 1982. godine. Nakabayashi, Kojima i Masuhara opisuju ga kao sloj smole, kolagenskih vlakana i djelomično demineraliziranog dentina koji nastaje infiltracijom i polimerizacijom metakrilatnih monomera u jetkani dentin. Razvojem tijekom godina adhezijski sustavi poprimali su sve bolja fizičkomehanička svojstva te se pojednostavila njihova uporaba spajanjem tri koraka adhezijskog postupka – jetkanja, priminga i bondinga – u dvokomponentne i jednokomponentne sustave. Primjena adhezijskih sustava neizostavan je dio većine grana stomatologije, a posebno restaurativne dentalne medicine, endodoncije i fiksne protetike. Iz tog razloga, adhezijski se sustavi ubrzano razvijaju i u budućnosti se očekuje njihovo unapređenje, kao i razvoj novih svojstava poput bioaktivnih i antibakterijskih. Adhesive systems mediate in bonding composite materials to dental hard tissues. They consist of a primer, basic coating which contains hydrophilic monomers, and a bond which is a final coating of polymerizing hydrophobic resin. Before the application of adhesives, it is required to prepare the surface of hard dental tissues by using organic acid which is called etching. Their use is based on adhesion which is defined as binding two different materials by attracting atoms and molecules. The primary principle of adhesion is the removal of minerals from hard dental tissues by etching and their exchange with monomers which bind micro-mechanically in the newly formed pores. The adhesion is differently achieved in enamel and dentin due to their differences in structure and reactions to etching. Adhesives are micro-mechanically connected to etched pores in enamel prisms while they diffuse in the dentin tubules and infiltrate collagen fibrils creating a chemical bond. The concept of adhesive systems starts to develop in 1955 thanks to Michael G. Buonocore who uses phosphoric acid to prepare the surface of enamel before the application of polymethyl-methacrylate resin. The definition of the hybrid layer in 1982 is also considered an important event in the development of the adhesive systems. Nakabayashi, Kojima and Masuhara describe it as a layer of resin, collagen fibrils and partly demineralized dentin which is formed by the infiltration and polymerization of methacrylate monomers in etched dentin. Over the years, physical and mechanical features of adhesives have improved, and their use is simplified by merging three procedural steps – etching, priming and bonding – into single-component and two-component systems. The use of adhesive systems plays an important role in almost every part of dentistry, especially in restorative dentistry, endodontics and fixed prosthodontics. Consequently, adhesive systems are developing rapidly and their improvement is expected in the future, as well as the development of new properties such as bioactive and antibacterial properties. |
