Synthetic Bone Substitutes in Combination with Growth Factors for Maxillary Sinus Floor Augmentation: A Mini-review.

Objective: Growth factors have been applied in maxillary sinus augmentation with clinically successful results. The purpose of this article is to evaluate the effectiveness of growth factors in combination with various synthetic scaffolds. Methods and Materials: A systematic review of studies examining the effects of synthetic materials in combination with growth factors were performed. Results: Twelve (1 human and 11 animal) studies were eligible for inclusion. Due to the great heterogeneity of the studies regarding design, materials and outcomes, a meta-analysis was not performed. The majority of the studies show a reduction in healing time and enhancement of bone formation within the subantral environment. Bone Morphogenetic Protein-2 and GDF-5 were the two most common osteoinductive factors studied, showing a significant effect on new bone formation. Moreover, initial outcomes of trials with stem cells genetic transformation, that results in increased production of growth factors, are positive and justify further research. Conclusion: The incorporation of growth factors into the synthetic scaffold may be beneficial regarding the healing process.

Distraction-like phenomena in maxillary bone due to application of orthodontic forces in ovariectomized rats.

Background: Orthodontic forces may not only influence the dentoalveolar system, but also the adjacent and surrounding cortical bone. Aim: Since there is very limited information on this issue, we aimed to study the possible changes in maxillary cortical bone following the application of heavy orthodontic forces in mature normal and osteoporotic rats. Materials and Methods: Twenty-four 6-month-old female rats were selected and divided into an ovariectomized group and a normal group. In both groups, the rats were subjected to a 60 gr* orthodontic force on the upper right first molar for 14 days. Results: In both groups, histological sections showed that the application of this force caused hypertrophy and fatigue failure of the cortical maxillary bone. The osteogenic reaction to distraction is expressed by the formation of subperiosteal callus on the outer bony side, resembling that seen in distracted bones. Conclusion: From this study we concluded that heavy experimental orthodontic forces in rats affect the maxillary cortical bone. The osteogenic reaction to these forces, expressed histologically by subperiosteal callus formation, is similar to that seen in distraction osteogenesis models.