Are there several types of composite resin cements? What are the differences?
Composite resin cements can be further classified according to the chemical composition into traditional full-adhesive resin cement and self-adhesive resin cements, both also differ in the bonding procedure. The full-adhesive resin cements require pre-treatment of the tooth structure and restorative material using separate adhesive systems. In this combination of the resin cement and the adhesive system, very durable chemical bonding can be reached.
To simplify the luting procedure and eliminate the need of using several components, the self-adhesive resin cements are a good choice for the daily busy practice, in which reliable bonding can be achieved in only one simple step of cement application, mostly without additional primers or bonding agents.
Full-adhesive composite resin
The process of adhesive luting with full-adhesive composite resin cements requires separate etching and priming procedures usually using a self-etch adhesive system as well as a primer for the restorative material such as a universal primer that can be used for different substrates including metal, ceramics and composites. These procedures are technique sensitive and intolerant to contaminations, therefore the luting process needs a dry oral environment avoiding any contamination, such as saliva or blood, preferably using rubber dam, as any contamination can compromise the bond strength. Therefore, inability to maintain dry field as in case of subgingival preparation margins is considered a contraindication for traditional full-adhesive luting. However, this method provides very durable bond strength, therefore it is the luting method of choice for minimal invasive non-retentive preparations, such as resin-bonded FDPs, labial and occlusal veneers and inlay-retained FDPs, in which the retention is mainly dependent on the adhesion.
Self-adhesive composite resin
Although the conventional cements are simple and fast in their use, they provide little or no adhesion at all and therefore they are not recommended in several cases. A simple but reliable method can be well accomplished by the use of self-adhesive resin cements as they can be considered the best alternative for full-adhesive adhesive luting in less critical situations that do not rely entirely on adhesion. Furthermore, self-adhesive resin cements are not as technique sensitive and intolerant to contaminations as traditional full-adhesive resin cements.
Typically, a MDP phosphate monomer is integrated in the self-adhesive resin cement, which is required to chemically bond to different substrates, making it possible for the resin cement to chemically bond to non-precious metals and zirconia as well as tooth substance. However, regardless of the self-adhesive resin cement, the use of a separate silane coupling agent is still required when bonding to silica-based ceramics (e.g. leucite, lithium silicate and lithium disilicate), hybrid ceramics and composite restorations.