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April 201418 Cosmetic Tribune for complete cure of any direct restoration. The restoration is evalu- ated for complete cure and then a layer of an unfilled resin is placed on the exposed GIC/ RMGIC/composite complex and cured for an additional 10 sec- onds. The matrix band is re- moved and the restoration is trimmed and polished as any typ- ical RBC restoration would be. I have found that an entire three-surface posterior resto- ration can be accomplished in less than three minutes once the matrix has been placed. Typ- ically, finishing the restoration can also be done in less than three minutes. This makes the direct posterior restoration quite efficient and beneficial to the cli- nician and the patient because we are providing a restoration that will help enhance healing of the dentition and reduce re- current decay and restorative failure. Nanotechnology in dental materials Nanotechnology involves the production of functional materi- als and structures in the range of 0.1 to 100 nanometers by various physical or chemical methods. Today, the development of na- notechnology has become one of the most highly energised dis- ciplines in science and technol- ogy because it can stimulate the creation of many new materials with previously unimagined ap- plications and properties. Several studies17,18 have shown that the inclusion of these types of nano-fillers and nano-fibres into the dental materials (dental composites and bonding agents) can improve the physical prop- erties by increasing the strength, polishability, wear resistance, aesthetics and bond strengths in many dental applications. It is also envisioned that the incorporation and utilisation of these nanoparticles in the form of nano-rods, nano-fibres, nano-spheres, nano-tubes and ormocers (organically modified ceramics) into dental restora- tive and bonding agents can cre- ate more biomimetic (life-like) restorations. This will not only enable these materials to mimic the physical characteristics of the tooth structure, but will also be able to facilitate the reminer- alisation of that structure. As Saunders states in his con- clusion, “such nano-restorative biomaterials could very cred- ibly be the next transfor-mative clinical leap” in restorative den- tistry. Giomers In that vein, an exciting ad- vancement in bioactive mate- rials is the development of gi- omer products (SHOFU Dental, Beautifil II, and Beautifil Flow Plus). These giomers are resin- based composites that contain pre-reacted glass ionomer par- ticles (S-PRG). These particles are made of fluorosilicate glass reacted with polyacrylic acid (just like a GIC), just before be- ing incorporated into the resin. This creates a new type of bioac- tive material. These giomer products dis- play properties in a manner sim- ilar to GICs19 : they release ions and recharge with ions from the oral cavity, inhibit plaque forma- tion and neutralise and buffer the acids of the mouth.20 No other composite material has this property to date. I use these giomers instead of tradi- tional nano-hybrid composites in my restorations because of these properties. They complete the entire biomimetic and bio- active nature of all the co-cure procedures that I create. The Beautifil Flow Plus prod- uct line has also expanded the way that I create restorations due to their unique viscosities. These materials can be stacked (Fig 15) and used in a restorative process I call the ‘modified resin cone technique’ (Fig 16). They can also be applied to create direct composite veneers that can be easily placed, sculpt- ed and highly polished (Fig 17). Easy placement, the ability to stack and maintain position and shape, plus their bioactive nature, make these materials a ‘game changer.’ Resin-modified, light-cured bonding agents Another advancement that I have been working with is a product that is a resin-modified, light-cured bonding agent (SDI, North America: Riva Bond LC). This product is a specially for- mulated liquid RMGIC that can be used to bond composite resto- rations in the traditional sense, used in traditional sandwich and modified sandwich techniques and, of course, used in the Co- Cure Technique. This concept is especially appealing in light of research that indicates RMGICs provide quite good marginal seal when used as a bonding agent on cut dentin surfaces.14 I especially like to use it with the Co-Cure Technique and when doing an- terior restorations. Using this technique I am able to get a completely biomi- metic, bioactive restoration in both situations because of the bioactive nature of the materials used. The technique for use of this RMGIC bonding agent with composite is as follows: 1) Etch with 37 per cent phos- phoric acid for five seconds 2) Wash and dry but do not desiccate 3) Triturate and apply the RMGIC bonding agent with a micro-brush and cure for 20 seconds 4) Place composite to fill the preparation and cure as appro- priate When I use this material in the Co-Cure Technique, I just substitute it for the traditional RMGIC material that I would have used otherwise. Resin-modified calcium silicates Another recent interesting product release is from Bisco and is called TheraCal LC. This light cured bioactive material is used to seal and protect the dentin-pulp complex. It is the first of a new class of internal pulpal protectant materials known as resin modified calci- um silicates (RMCS). It acts as a pulp capping and liner material. Calcium hydrox- ide (CH) has been the “gold” standard for pulp capping for many years. However, it has al- ways had difficulties in use as a liner under RBC adhesives. In fact, despite their frequent use, the success of CH based thera- pies is only 30 to 50 per cent.21 It has also been shown that traditional resin-based light- cured liners have been cytotox- ic to cultured odontoblast-like cells, while light-cured resin- based MTA cements presented the lowest cytopathic effects.22 Based on this, the creation of light-cured RMCS is a logical step in developing a solution for direct pulpal protection. Calci- um has been shown to be crucial to the formation of apatite, den- tin bridge formation and re-apa- tite potential of affected dentin. Additionally, alkalinity also seems to be contributory toward this goal. This combination in the RMCS material appears to form good, hard and thick den- tin bridges and stimulates den- tin pulp cells to turn into odoto- blastic dentin cells.23 This type of material repre- sents a promising new direction in direct pulp-capping clinical procedures with its ability to form apatite and further con- tribute to the formation of new dentin. Conclusion It is my belief that using bio- active materials in the provi- sion of care for my patients has been paramount to the success of the care I have been providing. In this way, I have provided ways to heal the dentition, enhance the resto- ration and improve the health of my patients. I believe we are on the threshold of further bioactive material advancements and that learning and incorporating these restorative materials into the day-to-day provision of care will continue to help our pa- tients, our practices and our pro- fession. DT Editorial note: A complete list of references is available from the publisher. United Kingdom Edition About the author Dr John C Comisi, DDS, MAGD, has been in private prac- tice in Ithaca, NY, since 1983. He is a graduate of North- western University Dental School and received his Bach- elor of Science in biology at Fordham University. He is a member of the American Dental Association and its tripartite organisations, the Academy of General Dentistry, the American Equilibration Society, the Internation- al and American Association of Dental Research, a research associate at New York University Dental School and an editorial board member of Dental Products Shopper Magazine. Comisi is a Master of the Academy of General Dentistry, and holds fellowships in the Academy of Dentistry International, the American College of Dentistry, the Pierre Fauchard Academy and the International College of Dentistry. He may be contacted at jcomisi@jcomisi. com. (Photos provided by Dr John C Comisi unless noted otherwise) page 17DTß Fig 11 Fig 12 Fig 13 Fig 15 Fig 16 Fig 17 Fig 14