cosmetic dentistry_ beauty & science

I 09 CE article _ bioactive materials I cosmeticdentistry 1_2013 restorations, called the Co- Cure Technique. This tech- nique is defined as the simultaneous photo-poly- merization of two different lightactivated materials that involves “the sequential lay- ering of GIC, RMGIC and composite resin prior to photo-polymerization and before the initial set of the GIC [which] enables an effi- cient single-visit placement of a [direct] restoration…”16 In the Co-Cure Technique, the composite restoration does not require a bonding agent be- cause the bonding agent is essentially the RMGIC. The RMGIC acts as the interface between the GIC and the com posite material. It combines the GIC, RMGIC and composite in a way to form what can best be described as a “monolithic biomimetic restoration.” This restoration is an “open sandwich” type of sandwich technique. That is, the GIC component is exposed to the oral environment (Fig. 13) at the gingival portion of the restoration. It is quickly and efficiently accomplished and has significantly reduced postoperative sensitivity compared with typical direct RBC techniques. I have been placing these types of direct posterior restorations since 2008. They have become the cornerstone of my practice. Techniqueprocedure(Fig.14) Afterplacementofanappropriatedentalmatrix, the technique incorporates the use of 37 per cent phosphoricacidtopreparethetoothforrestoration. Theacidisessentially“flooded”intothepreparation inasimilarmannertodoinga“total-etch”RBC.Itis, however, washed off after five seconds of place- ment. The tooth is then dried but not desiccated. The area remains slightly moist because the GIC that will be placed next is hydrophilic. Fill the preparation with the triturated GIC ma- terial up to the level of the DEJ, then immediately place the triturated RMGIC in a very thin layer to cover the GIC and walls of the preparation. Finally, place the composite over the previous materials to slightlyoverfillthepreparation.Withalargeround burnisher dipped in an unfilled resin material (i.e., Riva Coat by SDI or G-Coat by GC), wipe away the excess GIC and composite restoration material to create your margins and prevent ditching and white lines. The occlusal table of the restoration can then be compressed gently with a plastic occlusal ma- trix by either having the patient bite or by the op- eratorpressinggentlywithhisthumborforefinger to improve the coalescence of the three materials. This can help reduce the time involved in creating the final occlusion of the restoration by creating a functional occlusal table. The restoration is then cured for 30 to 40 sec- onds with an LED curing light that generates at least 1,500 mW/cm2. Appropriate light output is critical for all direct cured restorations, and as- surance that appropriate output is provided by the curing light is needed for complete cure of any direct restoration. The restoration is evaluated for complete cure andthenalayerofanunfilledresinisplacedonthe expose GIC/RMGIC/composite complex and cured foran additional 10 seconds. The matrix band is re- movedandtherestorationistrimmedandpolished as any typical RBC restoration would be. I have found that an entire three-surface pos- terior restoration can be accomplished in less then three minutes once the matrix has been placed. Typically,finishingtherestorationcanalsobedone in less then three minutes. This makes the direct posterior restoration quite efficient and beneficial totheclinicianandthepatientbecausewearepro- viding a restoration that will help enhance healing of the dentition and reduce recurrent decay and restorative failure. _Nanotechnology in dental materials Nanotechnology involves the production of functional materials and structures in the range of 0.1 to 100 nanometers by various physical or chemical methods. Today, the development of nanotechnologyhasbecomeoneofthemosthighly energized disciplines in science and technology because it can stimulate the creation of many new Fig. 12 Fig. 13