Objective: Clinical trials studied different materials and techniques for atrophied ridge augmentation regarding function implant stability and bone level. Microanalysis of the bone reaction to augmentation is still under investigation. The present study aims to examine the histological changes in augmented areas as well as the gene expression levels of one of the genes involved in bone regeneration.
Methods: 9 core biopsies were collected from subjects during implant placement after having their posterior maxillary region augmented with absorbable gelatin sponge six months earlier. The cores were studied by routine histology, histomorphometry and osteoprotegerin OPG gene expression level.
Results: Histological examination revealed active bone formation criteria in all specimens with variable presentation. Histomorphometry demonstrated that the new bone area percentage comprised about 30% (new bone 24.13 ± 5.01 %) & (mature bone 54.83 ± 12.13 %) of the total bone area percentage detected by Hematoxylin and Eosin and Masson's trichrome stain. Gene expression level of OPG revealed significant elevation (P = 0.017) when compared to normal standard control levels.
Conclusions: Based on histology, histomorphometry and gene expression findings posterior maxillary augmentation with absorbable gelatin sponge showed an elevated bone activity. However, it is still needed to verify if such effect resulted from the incorporation of gelatin sponge or the sinus membrane lifting only.