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10 Dental Tribune Middle East & Africa Edition | May-June 2015restorative Total-etch vs. Self-etch adhesives a case-dependent choice By Dr. Walter G. Renne, USA A dhesive dentistry with direct and indirect resto- rations has advanced tre- mendously since the first etch- and-rinse technique introduced by Buonocore for enamel-only adhesion. Enamel and dentin are both now routinely etched and bonded, procedures that have been proven in multiple studies to be safe and reliable when proper technique is fol- lowed. As the procedures ad- vanced, we now have adhesive systems that offer either etch- and-rinse (also known as total- etch) and self-etch options. The total-etch technique is still con- sidered the gold standard for bond strength to enamel, and self-etch adhesive systems have been compared to these to as- sess the relative bond strength with each. Adhesion is the most important step in all procedures associatedwithadhesivedentist- ry and with so many options— enamel or dentin or enamel and dentin bonding; total-etch or self-etch; and multi-bottle or one-bottle systems—there is much to consider before select- ing one. Both total-etch and self- etch adhesives offer reliable and repeatable results when proper- ly selected, and the fewer steps required, the more efficient the procedure. This saves chairside time for the clinician and the patient, reducing the possibility for error. Since the appropriate technique is case dependent, the typeofcasemustbethefirstcon- sideration. If there is a large area of enamel available for bonding and only a small area of dentin, the total-etch technique is often preferred, as it has been shown to result in stronger bonding to enamel than a self-etch tech- nique. Conversely, if a prepara- tion has a substantial area of dentin available for bonding and a lesser area of enamel (such as a large Class II), then self-etch is more frequently used. Which- ever adhesive system is chosen, it must provide for high bond strength, durable marginal in- tegrity, and be compatible with the restorative material. The cases below show the use of uni- versal adhesives for direct com- posite and indirect restorations. Case report 1 Direct Class II Restoration The patient in this case pre- sented with approximal carious lesions in teeth 12 and 13, which breached the enamodentinal junctions on the radiographs. Old preventive resin restora- tions were also present occlus- ally. It was decided that direct composite restorations would be placed to restore the 2 bicuspids. At the treatment appointment, after giving the patient local anaesthesia, a rubber dam was placed to isolate the teeth before preparation and provided a dry field during placement of the adhesive and composite restora- tions (Fig. 1). In this case, a total- etch technique was selected. During preparation of the teeth, minimal width boxes were cre- ated that extended sufficiently for caries removal but no further and the old preventive restora- tion removed. Since adhesion would provide for retention of the bonding agent, there was no requirement to ensure a re- tentive preparation form. For this case, I chose OptiBond Solo Plus (Kerr) as the adhesive. It consists of a phosphoric acid gel etchant and a separate primer/ adhesive that contains a filler to help strengthen the bond at the hybrid zone level, giving very high bond strengths with just 2 steps. After etching the enamel and dentin for 15 seconds, the etchant was rinsed off and the enamel and dentin gently dried without desiccating the den- tin. Next, the bonding agent was applied and lightcured for 20 seconds (Fig. 2) before the composites were placed as bulk fills using the SonicFill System (Kerr) and light-cured. The composites were then checked for occlusion, the mar- gins checked for any excess, and the composites were finished and polished using Progloss (Kerr) (Fig. 3). Case report 2 Indirect Ceramic Inlay in this case, a new patient presented with failed, old patchy composite restorations in tooth 20 (Fig. 4). Several areas of dif- ferent composites were present that had been placed at various times. On presentation, the pa- tient complained of sensitivity in this tooth when eating or drink- ing anything cold. On exami- nation, the bond between the restorations and the tooth had failed and the composites were found to lack marginal integrity. In addition, the tooth was found to have marginal leakage, stain- ing, and recurrent caries in the mesial box. This could have been due to the technique used, poor bond strength, or lack of compatibility between the ad- hesive systems and composite systems used at various times. > Page 11 Fig. 1. Preparations Fig. 2. Preparations isolated and after application of 2-step etch-and-rinse ad- hesive. Fig. 3. Final composite restorations. Fig. 4. Old composite restoration with poor marginal integrity. Fig. 5. Preparation completed. Fig. 6. CAD scan of preparation. Fig. 7. Proposed form of indirect res- toration.