| Grant number: | 06/01322-8 |
| Support Opportunities: | Regular Research Grants |
| Start date: | August 01, 2006 |
| End date: | October 31, 2008 |
| Field of knowledge: | Health Sciences - Dentistry - Oral and Maxillofacial Surgery |
| Principal Investigator: | Luiz Antonio Salata |
| Grantee: | Luiz Antonio Salata |
| Host Institution: | Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil |
Abstract
A number of filling biomaterials have been tested in clinical and experimental studies for sinus floor augmentation, including autogenous (bone and/or platelet-rich plasma PRP), homogenous, heterogeneous, alloplastic or a combination of these materials. The autogenous bone graft is regarded as gold standard because its intrinsic immunogenic-free characteristics, osseoinductive and osseoconductive properties. The disadvantages in using autogenous bone with this objective are: the need for relatively extensive amount of harvested bone to fill up sinus cavity; time-consuming practice; and donor site morbidity.In spite of the successful clinical outcomes with the techniques currently in use for sinus floor augmentation, there are some clinical and experimental evidences that the Schneiderian membrane is potentially osteogenic (Ellegaard et al.,1997; Haas et al., 2002; Gruber et al., 2004). To test this hypothesis, an experimental study was carried out by our group aimed at investigating implant osseointegration and stability after Schneiders membrane elevation with coagulum alone in monkeys. The membrane was kept up using two implants like tent poles in each sinus. One sinus was filled with autogenous bone and the other with the local coagulum. The implant stability was measured by resonance frequency analysis (RFA), the osseointegration assessed by bone-to-implant contact and the process bone deposition was examined through fluorescence microscopy. The results showed no difference as the groups were compared. Clinically, the application of the technique just described would be limited to those cases in which the residual bone ridge was wider than 6.0 mm, so that to avoid the implant primary stability from being compromised. Therefore, in the cases that insufficient bone hinders immediate placement of implants the use of coagulum alone would require an additional maneuver to prevent the membrane from collapsing until new bone is formed to allow implants installation and adequate anchorage.The objectives of the present study are: to propose and evaluate the use of an absorbable dome-shaped device - synthesized by The University of Uppsala (Sweden) - in two-stage sinus floor augmentation procedure, without using additional biomaterials. The advantages of this innovative technique in implant dentistry, would be: 1) to abolish the use of high cost bone substitutes biomaterials (alloplastic and xenogenic); 2) to diminish surgery time for sinus floor augmentation procedures; 3) to avoid autogenous bone graft harvesting frequently associated with donor site morbidity.Eight tufted capuchin monkeys will be used in this study. Four months after 1st, 2nd, and 3rd premolars and 1st molar extractions the animals will be subjected to bilateral Schneiderian membrane elevation, dome-shaped absorbable device implantation in both sinuses, and installation of one implant 3.75 mm in diameter and 8.5 mm in length (MKIII TiUnite, Bränemark System, Nobel Biocare®, Gothenburgo, Sweden) in one sinus only. Following six months 4 animals will be sacrificed for histology and the remaining 4 will undergo a third surgery for installation of one implant on the contra-lateral sinus. The latter animals will be sacrificed three months later. The implant stability (RFA) will be measured at the time of dome implantation (time zero) and six and nine months afterwards. The osseointegration of the implants (bone-to-implant contact) and bone deposition inside the sinuses (bone area) as well as the process of dome degradation will be assessed through histology and histomorphometry. (AU)
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