Predictable outcomes for sinus augmentation procedure

Dental Learning Hub: Have similar studies been conducted elsewhere?
Galindo-Moreno: Different materials have been tested for sinus grafting in the past, although there is a general consensus that any type of material is adequate. Despite this, we consider that it is neccesary to optimize the techniques and the materials we are using. Anorganic bovine bone has been tested in multiple studies showing good clinical and histological outcomes. For this reason, we believe it is a good control material.

On other hand, bioactive calcium phosphosilicate-like crystals have been developed as bone grafting material. This material is indicated in filling bony voids or gaps, without affecting the intrinsic stability of the osseous structure. However, thus far only limited research has been conducted to test this material in sinus augmentation procedures. Sinus grafting constitutes an adequate model to study patterns of regeneration because the graft doesn´t bear any disturbance during healing. To our knowledge, there are no studies that evaluate the behaviour of this new material in sinus grafting.
 

Dental Learning Hub: Why did you use a combination of autologous bone and synthetic bone materials in the grafting procedures?
Galindo-Moreno: Some studies, as Wallace´s meta-analysis, has shown that the combination of materials can provide better clinical success rates than biomaterial alone, used as graft material. There are a number of advantages to using this kind of combination:
Firstly, autogenous bone is still the gold standard because it is the only material that provides osteogenesis, i.e. cellularity, a unique and very important property. But there are some concerns about its use because a second surgical field is required, however this is solved by just using the supracortical sinus maxillary bone collected by a scraper, instead of using drills to remove bone to access the sinus cavity.
 

No second surgical field is needed with our technique, and we have unlimited supplies of grafting material. By using other biomaterial we reduce the amount of autogenous bone needed. At the same time, autogenous bone has inadequate resorption rates, that can compromise the viability and durability of the final outcome. So, by adding other biomaterials, as anorganic bovine bone, we can get an adequate scaffold with osteoconductive properties which maintains the dimensional stability of the graft during the healing. This material has a very slow resorption rate, so new material such as silicates, can improve the properties of the grafts, showing quicker resorption rates and the possibility of being replaced by new vital bone in a shorter period of time.
 

Dental Learning Hub: What were the most important outcomes from your study?
Galindo-Moreno: We have found that this combination of biomaterials produces a higher amount of new vital bone, higher amount of non mineralized tissue, and quicker resorption of foreign particles, in comparison with a well-tested material such as anorganic bovine bone (although our results don´t show a statistical significance). We knew the limitations of our study, because it was a pilot clinical trial, so we need more patients in order to obtain definitive results, but this study gave us an idea about the qualities of this new material. We consider that the quantity of vital bone that we found is good for osseointegration when implants are placed in these grafts, corresponding with the amount of vital bone that used to be in the maxillary bone location.
 

Dental Learning Hub: How do your results make an impact on implant dentistry and related sinus augmenting treatment protocols?
Galindo-Moreno: This study brings new data about the different protocols we can use in sinus augmentation. We feel that new studies must be done in order to clarify some important aspects about grafts healing, not only in sinus procedures. We are aware of the general opinion in the scientific community that any material is good for sinus grafting. This belief could be as a result of pressure from manufacturers, or because of different motives on scientific aspects, so any new concept coming for these types of studies can contribute to improving our knowlegde and decision tree analyses about how to do the best for our patients. 
 
Dental Learning Hub: Will you conduct further research on this subject in the future?
Galindo-Moreno: Our group has worked hard over the past years on studies relating to sinus grafting techniques. We will soon publish new papers on topics from the different aspects in graft healing, for example, the importance of the non-mineralized tissue, the remodeling behaviour of the graft material, mesenchymal stem cells that can be presented in graft material, angiogenesis and osteogenesis or even comparison between materials in a similar way to this study.
 

We consider sinus cavity as an ideal model to study cellular and biochemical events that allow us to better understand how things work after surgery, in order to achieve higher predictibility in our clinical outcomes. An interesting and large field lies open in front of us, let´s get to work!
 

Full article
Clinical and histologic comparison of two different composite grafts for sinus augmentation: a pilot clinical trial Clinical Oral Implants Research
Authors: Galindo-Moreno P, Ávila G, Fernández-Barbero JE, Mesa F, O'Valle-Ravassa F, Wang H-L.