Materials for Long Span Implant-Supported Reconstructions: An Alternative to Existing Survival Issues

Hi, I’m Estevam Bonfante. I teach at the department of prosthodontics and periodontology at the University of Sao Paulo in Bauru School of Dentistry, Brazil. One of my research focus is the clinical and laboratory performance of all ceramic materials, especially when used for implant supported reconstructions. Today, we’re going to talk about the current challenges that we have on the performance of short and long span prostheses. As we know, there are so many restorative materials to choose from, and novel materials are released every day. So to help us understand where these materials belong to and how they should be used, this classification proposal has divided all ceramic and ceramic like materials in three families, which are glass matrix ceramics comprised of materials that present any extent of glass phase within their matrices, polycrystalline ceramics that do not present any glass phase, and resin matrix ceramics that are polymer based materials highly filled with glass or ceramic particles for reinforcement. If we think of representative materials within this classification scheme, a frequently used material of the glass matrix ceramics is lithium disilicate. Within the polycrystalline ceramics, for instance, is zirconia used either as a substructure or as a monolithic restoration. And there are several examples in resin matrix ceramics such as zirconia or feldspathic porcelain filled in a resin matrix and also glass fiber reinforced composites, which we shall discuss today. Most of these materials are available in blocks or discs for milling in CAD/CAM systems. So although in this classifications proposal manuscript, you may find that the majority of all ceramic materials description and indications according to the manufacturer’s instructions, the clinical performance of all ceramic materials, especially for large span implant supported reconstructions, is still a matter of concern. When we look at the systematic reviews from the latest European Academy for Osseointegration consensus in twenty eighteen, it becomes evident that there are still major challenges for improvement of porcelain fused to zirconia for it to become the standard of care. When used for fixed dental prostheses over implants, for instance, the last EAO consensus showed that technical complications including porcelain fractures occurred in twenty two point eight to fifty percent of the cases compared to only eleven percent of the patients that had received porcelain fused to metal reconstructions after five years. It was also detected that full arch implant supported prosthesis fabricated from porcelain fused to zirconia presented nearly thirty five percent of porcelain fractures over five years. So the EAO twenty eighteen consensus eventually concluded that such fracture rates of the veneering ceramic were clinically unacceptable. So there is not only opportunity but also a real need of novel metal free materials. So if one considers the high porcelain chipping rates of three unit and larger span prostheses, it can be suggested that materials should ideally present high strength, should be easy to fabricate and easy to adjust and repair if a fracture occurs. Within this context, glass fiber reinforced composites have gained attention because they’re lightweight, highly resistant materials that present elastic modulus more close to natural tissues such as bone. Although fiber reinforced composites can be handmade, our focus is on the use of reliable and industrially provided blocks or disks for CAD/CAM milling, which creates opportunity for several prosthesis designs, including partial or full arch fiber reinforced frameworks to be either hand layered with resin composites or acrylics, or to even receive milled all ceramic materials that can be bonded to it. Well, it also includes indications for removable partial denture frameworks and conventional dentures. Now, would like to invite you to see the previous and current research results of a glass fiber reinforced composite material named TRINIA that is on the market since a while now. When indicated for three unit posterior fixed dental prosthesis, it presented survival rates as high as porcelain fused to metal prostheses and higher than veneered zirconia, even when fiber reinforced frameworks presented minimal connector cross sections, such as three square millimeters. Such findings consequently allowed its indication for five unit prostheses, such as this one that presents individual abutment shape that may receive individual crowns or bridges. The one on the top was hand layered with Ceramage, an indirect resin composite material, and failed during fatigue at loads above a thousand newtons, which exceeds maximum voluntary bite forces. And the other one on the bottom received the CAD/CAM milled ceramic like material named Shofu HC and survived even higher loads close to two thousand newtons. Well, basically, the major clinical implication is that TRINIA is not only resistant, but most importantly, it allows easy repair since it only requires addition of any direct or indirect resin composite restorative material. Altogether, these findings brings light to the last EAO consensus report, which stated that no all ceramic material could be safely indicated for large span implant supported reconstruction. So teeth colored or pink TRINIA already has published follow ups of up to five years of clinical use for upper and lower full arch implant supported prosthesis presenting prosthetic survival rates of ninety four percent. Most interesting is its use for distal cantilever extensions over twenty five millimeters, which is allowed due to its flexibility. Well, I hope you enjoyed this presentation, and I look forward to bringing more information in the near future. Thanks for watching.