We thank the Zimmer Corporation for sponsoring Terri Oto CTBS as our speaker for the September Study Club.
In the past, we have had the pleasure of having Terri present to our study club and her lecture was very well received. The following is a synopsis of her most recent lecture, “Technology of Graft Materials.”
Tissue banks are highly regulated government approved organizations and there are over 500 registered by the FDA at this time. Each company strives to maintain a strict level of quality control to remove high-risk donors and ensure safe tissue handling procedures. This high level of oversight is needed to ensure the quality of tissues available and to prevent the possible transmission of diseases. Her products through Zimmer are CE approved for European use and are recognized by the governments of 46 countries. They utilize an advanced tissue handling process that has been in use since 1971 to ensure over forty-five years of usage and five million implant cases with no cases of disease transmission.
When choosing graft material is important to note that not all graft materials are the same even if they originate from the same source. This can be attributed to the variety of processing and packaging differences for each company. In general, there are four types of grafts to choose from. The first type of graft is an autograft which is an autogenous graft taken from a different site on the same individual. Next is an allograft which is a graft from the same species but not the same individual. These can be treated to become mineralized, demineralized or turned into a putty or paste. A great example of this type of graft is Zimmer Puros. The third type of graft available for use is a xenograft, which is a graft from a different but compatible species. Such grafts are often equine, bovine or porcine. One of the most well-known and well-documented xenografts is bovine graft, Bio-Oss. Finally, there are a variety of synthetic grafts available, most notably Alpha TCP, Beta TCP, HA, Biologics and Calcium Sulphate. Each of these graft types will have different healing and handling characteristics. Terri stressed the importance of picking the correct product for your specific application.
A good graft should have several important characteristics. First it should present outstanding and consistent clinical performance. Second it must have good handling characteristics and third, it must have surface characteristics that mimic natural bone. Finally, it is imperative that the graft shows good collagen integrity.
The tutoplast procedure used by Zimmer for the Puros product line takes 39 days to complete. There are other companies whose process is done in 5 days. The reason that the Tutoplast process takes so long is that they are trying to be as gentle as possible with the bone in order to retain its most important characteristics. Antigens are removed, pathogens are inactivated, preservation of the tissues is ensured and inactivation of bacterial and viral elements is confirmed to maintain a 5 year shelf life.
When it comes to Puross, mineralized bone is more effective than demineralized. The .25 to 1 mm chips are the most advantageous sizes. Cancellous bone is best for sites that you plan on reentering within 3 months such as extraction sites. The Cortical chips are more advantageous in sites that you will allow to heal longer as you would do with sinus grafts, as well as a large particle size such as 1 -2 mm. It was stressed that the bone product you choose should be based on reentry time to the area.
The discussion continued with information on MinerOss and RegenerOss, as well as the company Life Net, who produces the bone products for Salvin, Straumann, Creoss and others. They use a much shorter treatment process that involves sonication and centrifugation. RegenerOss, has a very small particle size, and large surface area. This makes it ideal for small defects such as perio furcation areas or voids adjacent to immediate implant placements
In regards to xenographs, Bio-Oss has long been touted for its excellent track record and consistency. Bio-Oss is sintered Bovine bone, which undergoes a high heat process that renders the bone a virtual ceramic. It acts more like a non-resorbable material in which the patient’s bone will form around it but not replace it. It is especially useful for the maintenance of ridge volume in areas where future implants are not likely to be placed. Again, Bio-Oss has a tremendous long-term track record. Studies have shown the product present 9 and 14 years after placement with little to no change.
In closing, any graft should show the properties of attraction, adhesion and proliferation. When dealing with products the clinician should remember to not over-pack with excessive force in order to allow space for proper bone regeneration. It is also important to keep in mind the reentry time and clinical reasons for the graft. In our clinical experience, the better the vascular bed, the better the end result.