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Figure 1. Pretreatment (bonding protocol) of lower left quadrant to be restored with direct resin nanohybrid composite, showing a rubber dam in place. |
Figure 2. Teeth have been prepared, removing unsound tooth structure and defective amalgam restoration. |
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Figure 3. Preparations are etched past the margins with phosphoric acid etchant gel. |
Figure 4. After rinsing away the etchant and properly drying, OptiBond FL primer (Kerr) was applied 2 times and then air-dried to evaporate the alcohol solvent. |
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Figure 5. Following proper application of the primer, OptiBond FL resin component was applied and then light-cured. |
Figure 6. Herculite Ultra nanohybrid composite (Kerr) was applied and light-cured in multiple layers, then sculpted and polished, creating a restoration that mimics natural teeth in function and aesthetics. |
During preparation, defective materials, decay, and unsound tooth structure are removed to ensure a firm base for bonded materials to adhere to and properly seal the tooth (Figure 2). Phosphoric acid gel (Gel Etchant [Kerr]) is applied to the entire preparation beyond marginal areas to ensure proper adhesion of the bonding agent (Figure 3). After 30 seconds, the etchant is rinsed away with water until the tooth is clean. My personal choice in a bonding agent that I have used with predictable success for nearly 20 years is OptiBond FL (Kerr). It is a 2-component primer/resin system that has an alcohol-water base, allowing a larger window of bonding opportunity when considering how wet/dry the dentin should be after etching. In my protocol, I dry the dentin (not “bone” dry) for about 5 to 10 seconds to remove water after rinsing. The water component of the mixture allows some rewetting of dentin and proper activation of the chemistry. My preference is unidose packaging to ensure the manufactured chemistry ratio for each procedure we perform. The adhesive primer component is applied in 2 separate layers with air drying after each application for 5 to 10 seconds to evaporate the alcohol solvent (Figure 4). It is critical that the alcohol is allowed enough time to evaporate so that the next layer, the bonding resin, can be properly cured. Meticulous technique at this step greatly affects our success in preventing the problems of microleakage and sensitivity. The bonding resin in the second component is brushed over the primer layer on all surfaces past the marginal areas then light-cured for 10 seconds with a Demi LED curing light (Kerr) (Figure 5). After curing the bonding resin, nanohybrid composite (Herculite Ultra [Kerr]) is placed in multiple layers of less than 2 mm and cured to control polymerization shrinkage. After placement and curing of the final layer of the composite, the restoration is sculpted and then polished with carbide finishing burs (H48L-012 and H379-018 [AXIS Dental]) and silicone polishing cups (Kerr Hawe HiLuster [AXIS Dental]) to maximize the final polish. The final restoration should effectively seal the tooth, creating a durable, comfortable, long-term restoration (Figure 6).