Sažetak sa skupa
Biological Based of Dentine Hybridization
Zoran Azinović
Sažetak
The picture of the dentine structure is closely connected with the discovery and improvement of research techniques- light microscopy and scanning electron microscopy. Results of light microscopy were limited. Rapid development of dentine structure investigation begins with the use of scanning electron microscopy. Detailed knowledge of the hard dental tissue structure was the basis for the development of the concept of modern adhesive restorative treatment. Adhesion to enamel was not the problem, either experimentall, or clinically. Adhesion to dentine has a great number of specific characteristics and varieties. Further factors are important regarding the adhesion to dentine:
1. Biological bases of the substrate,
2. Condition and response of the pulp/dentine complex to the adhesive restorative treatment,
3. Material selection.
Modern concept of adhesion to dentine is based on the hybrid layer as a bond between dentine and resin, hard dental tissues and restorative materials respectively. The hybrid layer in the dentine consists of a monomer-infiltrated demineralized dentine, smears layer remnants, polymerized resin, resin-infiltrated collagen fibrils and hydroxyl- apatite crystals.
Distribution and interrelationships between structural elements of dentine have great influence on the form and quality of the hybrid layer. Heterogenous structure if dentine determines further specific properties of the dentine: permeability, humidity, physical properties (hardness, strength, elasticity). This dentine structure and dentine physiology variety determines adhesion to dentine as a complex interaction between biologic material (dentine) and adhesion system.
Most teeth that require adhesive restorative treatment are carious or have had a previous caries lesion. A number of tissue changes in the dentin and pulp take place as a result of caries (formation of tertiary dentine, sclerosis of the dentinal tubules, cellular changes in the pulp). Apart from caries-effected dentine, sclerosis takes place in the exposed, abraded, cervical dentine. Both types of dentine sclerosis prevent resin tag formation. Bond strength values are reduced in comparison to bond strenght on the normal, physiologic dentine surface. Adhesive system selection is a very important factor for hybridization and bond durability. Each adhesive system contents further components: acid, primer and adhesive resin. Multi-bottled adhesive system were used until 1994. These system required application in multiple steps.
After chemical treatment, hybridized dentin is formed in the subsurface. There is greatest change in the volume ratio between minerals, water and resin. The rate of collagen fibrils reamins the same. New chemical and physical properties of dentin and resin are developed due to the formation of the hybrid layer.
Ključne riječi
Hrčak ID:
3050
URI
Datum izdavanja:
15.9.2003.
Posjeta: 2.264 *