Purpose: The aim of this study was to investigate the effects of deproteinized bovine bone (DBB, Bio-Oss ® ) and freeze-dried bone allograft (FDBA, SureOss ® ) on bone healing during maxillary sinus floor augmentation (MSFA) using histology, immunohistochemistry, and gene expressions of the marker genes including Runx2, Opn, Ocn, Col1a1, Rankl, and Tnf-α.Materials and Methods: Fourteen participants who required two-stage maxillary sinus augmentation were randomly assigned to DBB and FDBA bone grafting groups.Six months after the sinus augmentation procedure, bone samples were collected before implant placement with a trephine bur. Gene expression of Runx2, Opn, Ocn, Col1a1, Rankl, and Tnf-α of the bone samples was assessed by real-time polymerase chain reaction as a primary outcome. Histological analysis of H&E-stained sections, immunohistochemistry for OPN quantification, and CBCT-based bone tissue examination were performed to investigate the bone healing effects of DBB and FDBA substitutes.Results: The FDBA treated group showed higher gene expression when compared with the DBB treated group in Opn (2.83 ± 1.23 vs. 1.40 ± 0.69; p = 0.04), Runx2 (1.49 ± 0.44 vs. 0.67 ± 0.14; p = 0.01), and Rankl (2.34 ± 0.85 vs. 0.69 ± 0.39; p = 0.03). In the DBB treated group a downregulated expression was found of Ocn relative to maxillary edentulous bone (1.18 ± 0.40 vs. 2.51 ± 0.78; p = 0.02). Conclusion:Two-stage maxillary sinus augmentation with FDBA upregulated specific bone remodeling genes when compared to DBB. The outcome of gene expression matched with the ones for OPN immunoreactivity, being higher in the FDBA group.FDBA had an expression pattern similar to native bone and showed stronger expression of bone forming related-genes suggesting it may be clinically preferable over DBB. This clinical trial was not registered prior to participant recruitment and randomization (clinical registration number TCTR20221217002).

Quality of bone is an important factor contributing to the success of dental implants. The bone height in maxillary posterior area sometimes is not enough and might pose risks for placing dental implants. Maxillary sinus augmentation with bone substitutes is used for filling and correcting bony defects. This study aims to determine the differences in gene expressions of TNF-alpha, RUNX2, COL1A1, ALP between xenograft (Bio-Oss®) and allograft (SureOss®). Patients who needed two-stage maxillary sinus floor augmentation were included (n=13). Patient who had dental implant at posterior maxilla without bone substitutes was also used in immunohistochemistry analysis (IHC) (n=1). Bone samples were collected using trephine bur 2 mm internal diameter. Quantitative real-time PCR (qPCR) method was used for studying gene expression (n=10). Immunohistochemical staining of ALP was used to visualize the area of osteogenic activity (n= 4). The results of qPCR showed higher RUNX2 expression of allograft when compared to xenograft (p<0.05). Although, TNF-alpha, COL1A1 expression was not statistically different between groups. Immunohistochemistry staining of both samples also showed similar intensity and expression of ALP. The data suggested that gene expression levels of TNF-alpha and COL1A1 were not significantly different between bone grafted with Bio-Oss® and SureOss®. However, the expression of RUNX2 was significantly higher in SureOss®. Nevertheless, result from IHC study showed similar characteristics between both groups.