Technique: How to create simple direct resin restorations
Two cases showing the exciting new possibilities in restorative dentistry.
Direct resin restorations have changed drastically since I graduated dental school 30 years ago. Adhesives no longer require acid etching of the dentin and enamel to achieve a bond. Self-etch adhesives were a step forward and advanced to achieve comparable bond strengths to dentin that were being reported with total-etch adhesives. Yet, enamel still required some treatment (acid etching or mechanical) to get a predictable bond to this surface with the self-etch adhesives. The next step forward, selective-etch allows the practitioner to decide when and where to etch depending on the clinical situation.
Bond Force® (Tokuyama Dental America, Encinitas, California) a seventh generation self-etch adhesive single component, fluoride releasing bonding agent provides an extremely strong bond to enamel and dentin with a patented SR (Self Reinforcing) monomer.1 This SR monomer cross-links to apatite and calcium ions on the tooth surface forming a strong bonding layer when light cured. Requiring only a single application, it can be used on both cut/uncut enamel and dentin, allowing a selective-etch approach. Fluoride releasing by the adhesive modifies adjacent dentin, resulting in secondary caries prevention with an acid-base resistant zone (super dentin) is observed under the hybrid layer of the bonded zone.2 Bond Force offers low technique sensitivity allowing its use in moist, wet or dry conditions with a low film thickness.
Estelite® Sigma Quick (Tokuyama Dental America), a universal, 100% spherically filled composite, with a filler weight of 82% (71% volume) uses a supra-nano monodispersing spherical filler. The supra-nano monodispersing spherical filler particles easily produce an extremely high surface gloss when polished. As the filler particle diameters are relatively uniform, and the particle size can be controlled by filler synthesis reaction times.
The catalyst technology adopted for Estelite Sigma Quick composite is the Radical Amplified Photo-polymerization initiator (RAP technology™).6 This initiator balances the high polymerization activity needed to cure the resin with short exposure times (one-third of that required by conventional products), but provides stability in ambient lighting so premature setting isn’t initiated before the practitioner is ready to light cure the material.