Sinus Floor Augmentation

Rehabilitation of the posterior maxilla with dental implants is frequently complicated by insufficient residual bone height resulting from alveolar ridge resorption and maxillary sinus pneumatization. Lateral sinus floor elevation has become a predictable and widely accepted procedure for increasing bone volume and enabling implant placement in severely atrophic posterior maxillary sites. The long-term success of this procedure is largely dependent on the grafting material used to maintain space beneath the elevated Schneiderian membrane and promote new bone formation. Deproteinized bovine bone mineral (DBBM), commonly known as xenograft, remains the most extensively documented grafting material for sinus augmentation due to its osteoconductive properties, volumetric stability, and favorable long-term clinical outcomes. However, xenografts are characterized by slow remodeling and prolonged persistence of residual graft particles, which may delay replacement by vital bone. Consequently, strategies to enhance the biological activity of xenografts and accelerate bone regeneration have become an area of considerable research interest. Leukocyte- and platelet-rich fibrin (L-PRF) is a second-generation autologous platelet concentrate containing a fibrin matrix enriched with platelets, leukocytes, cytokines, and growth factors including platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and transforming growth factor-β (TGF-β). These biological mediators may enhance angiogenesis, accelerate wound healing, stimulate osteoblast proliferation, and improve bone regeneration. Several studies have demonstrated promising outcomes when L-PRF is used in sinus augmentation procedures. Mazor et al. reported successful bone formation and implant placement following sinus augmentation using PRF as the sole grafting material after six months of healing. Histological analysis demonstrated the formation of newly regenerated vital bone within the augmented sinus compartment. More recently, Cortellini et al. conducted a randomized controlled trial comparing L-PRF block and DBBM in lateral sinus floor elevation. Although both techniques allowed successful implant placement after six months, differences in volumetric stability and graft remodeling were observed. The authors suggested that L-PRF-containing grafts may represent a biologically active alternative capable of enhancing healing while maintaining sufficient bone volume for implant placement. Pichotano et al. further demonstrated that combining L-PRF with DBBM accelerated bone maturation and facilitated earlier implant placement when compared with xenograft alone. Histomorphometric findings revealed greater percentages of newly formed bone and reduced healing times in the L-PRF group. Despite these promising findings, the available evidence remains limited, and there is no clear consensus regarding whether the addition of L-PRF to xenografts results in clinically significant improvements in bone regeneration, volumetric maintenance, and implant site development. Therefore, a randomized controlled clinical trial comparing xenograft alone versus L-PRF block combined with xenograft during lateral sinus floor elevation is warranted.

Maxillary posterior area is the most challenging site for dental implant placement. Indeed, complex remodeling processes, resulting in changes of the maxillary sinus and shape of the alveolar ridge will cause difficulties in rehabilitating the posterior maxillae sites. Various techniques have been proposed in order to achieve the necessary bone volume for the placement of long term successful implants. However, unbalanced crown to implant ratio remains a risk factor after successful dental implants installation following sinus graft. No study on humans assessed the effect of apical positioning of the implants in posterior grafted sites (sinus graft or sinus graft + vertical GBR) on the following clinical parameters: The peri-implant bone remodeling (vertical bone loss (mm) and probing depth (mm) around the implants, crown bulkiness, emergence profile and crown height, and Patients satisfaction, food impaction (PROM)). This study will elucidate these points and based on the parameter's results, suggest a treatment based classification facilitating the treatment decision-making of the clinicians in case of an atrophic posterior maxilla; aiming to ensure a long-term successful supra-implant rehabilitation which will maintain its bio-mechanically and biological success.

This research aims to investigate the influence of alveolar ridge preservation, after extraction of maxillary posterior teeth, on the potential need of sinus floor augmentation procedures (that include lateral or crestal sinus augmentations). From peri-apical radiographs, maxillary posterior teeth will be divided into 4 groups according to the relationship of their apexes with the sinus. Then, the patients will be divided into 2 sub-groups: unassisted socket healing (only extraction) and ARP group (extraction + ARP) and their CBCT scans before implant placement will be collected. The CBCT scans should be at least 4 months post-extraction and ARP. Depending on the residual bone height, patients will be divided into 3 categories, according to the ABC classification: 1. In need of lateral sinus floor augmentation 2. In need of crestal sinus floor augmentation 3. No need for sinus floor augmentation, therefore, implant placement. These divisions will be conducted, according to: \- The residual bone height (RBH) which is the height in mm from the alveolar ridge crest to the lowest point of the maxillary sinus floor. The results of the proposed hypothesis are verified and interpreted after statistical analysis.

The goal of this research project is to assess the clinical performance and degradation of bioresorbable Mg- based pins for membrane fixation in patients with sinus floor elevation.

Through randomized controlled trials, investigators will recruit participants who need maxillary sinus floor elevation with different residual bone height, and utilize the maxillary sinus buccal bony window during the surgery. Then investigators will gather the related information of participants, collect and analyze their CBCT data, in order to help surgeons select the best operating method for different patients.