Clearance of Bone Substitute in Gel Form Accidentally Dispersed into the Sinus Cavity during Transcrestal Maxillary Sinus Floor Elevation: Two-Case Report

Sinus membrane perforation is the most frequent intraoperative complication occurring during maxillary sinus floor elevation. Although numerous techniques for perforation management are present, grafting material dissemination may still occur, representing a potential trigger factor leading to acute or chronic sinusitis. This case report describes two cases of xenogeneic bone substitute in gel form accidentally dispersed into the sinus cavity during maxillary sinus floor elevation with a transcrestal approach. In both cases, immediately postoperative radiographic imaging showed an important amount of gel graft dislodged into the sinus cavity as a consequence of hidden perforations that remained undetected during surgery. Patients were monitored for 6 months after surgery and reported no signs or symptoms related to possible sinus disease. Control radiographs showed no sinus membrane hypertrophy and/or presence of residual disseminated gel, confirming complete clearance of the accidentally dispersed graft through the ostiomeatal complex. In order to minimize postoperative complications, bone substitutes in gel form could represent an interesting alternative to granular grafts for their easier clearance from the maxillary sinus cavity in case of accidental dissemination during sinus augmentation procedures.

Effects of Platelet-rich Fibrin on Osteogenic Differentiation of Schneiderian Membrane Derived Mesenchymal Stem Cells and Bone Formation in Maxillary Sinus

BackgroundThe existence of mesenchymal stem cells (MSCs) in Schneiderian membrane has not been determined. The aim of this study is to investigate whether there are MSCs in Schneiderian membrane, and the effect of platelet-rich fibrin (PRF) on osteogenic differentiation of these cells and on new bone formation in maxillary sinus after maxillary sinus floor elevation.MethodsSchneiderian membrane derived mesenchymal stem cells (SM-MSCs) were isolate from rabbit maxillary sinus. Cells were identified by flow cytometry and multipotential differentiation. Real-time cell analysis assay, fluorescence staining, transwell assay, and wound healing assay were used to determine the effects of PRF stimulation on cell proliferation and migration. The osteogenic differentiation ability of cells stimulated by PRF or osteoinductive medium (OM) was evaluated by alkaline phosphatase (ALP) staining, alizarin red staining, PCR and Western blot. Equivalent volume Bio-oss and the mixture of Bio-oss and PRF were used as bone graft materials for maxillary sinus floor elevation. Micro-CT, bone double-staining, HE staining, Masson staining, and toluidine blue staining were used to evaluate the osteogenic effect in 8 and 12 weeks after surgery.ResultsThe cell surface markers were positive for expression of CD90, CD105, and negative for expression of CD34, CD45. SM-MSCs had the ability of osteogenic, adipogenic and chondrogenic differentiation. PRF can stimulate proliferation, migration and osteogenic differentiation of SM-MSCs, which is achieved by up-regulating ERK 1/2 signaling pathway. PRF can accelerate the formation of new bone in maxillary sinus and increase the amount of new bone formation. ConclusionsMSCs exist in Schneiderian membrane, and PRF stimulation can promote cell proliferation, migration and osteogenic differentiation. The application of PRF in maxillary sinus floor elevation can accelerate bone healing and increase the quantity and quality of new bone.

Morphometric and histomorphometric evaluations of high-purity macro/microporous beta-tricalcium phosphate in maxillary sinus floor elevation: preliminary results on a retrospective, multi-center, observational study

Background The present study examined the effectiveness of high-purity macro/microporous beta-tricalcium phosphate (HPMM β-TCP) as a bone grafting material for maxillary sinus floor elevation by morphometric, histopathological, and histomorphometric evaluations. Methods Ten unilateral maxillary sinus floor elevation procedures using 100% HPMM β-TCP were performed in 10 patients. Morphometric evaluation was carried out by computed tomography (CT) imaging immediately after augmentation and prior to dental implant placement 7 months later. Histopathological and histomorphometric evaluations were carried out by bone biopsy retrieval at the time of dental implant placement 7 months after sinus floor elevation. Results All 10 sinus floor elevations were successful. Morphometric evaluation by CT showed that the vertical height and volume gained by sinus floor elevation decreased 7 months after surgery. Histopathological evaluation of bone biopsy retrieval specimens showed no signs of inflammation at the newly formed bone area and the native alveolar bone area. New bone formation was observed at the cranial side from the native alveolar bone. The newly formed bone had a trabecular structure and was in intimate contact with the HPMM β-TCP material. Histomorphometric evaluation of bone biopsy retrieval specimens showed an average new bone volume of 33.97% ± 2.79% and an average residual HPMM β-TCP volume of 15.81% ± 4.52%. Conclusions In this study, HPMM β-TCP showed osteoconductive properties for vertical augmentation of the atrophied maxilla by means of a maxillary sinus floor elevation procedure allowing subsequent dental implant placement after a 7-month healing period.

Minimally Invasive Lateral Approach through Circular Window with a Diameter of 5 to 6 mm for Maxillary Sinus Floor Elevation with Simultaneous Implant Placement: Retrospective Study

The aims of this study were to propose a minimally invasive lateral approach technique for maxillary sinus floor elevation (MSFE) with simultaneous implant placement and to evaluate the surgical outcome and complications of this technique. This study reviewed 49 surgeries of MSFE with simultaneous implant placement (n = 83) using a minimally invasive lateral approach. A circular shape window with a diameter of 5 to 6 mm and an area of 20–30 mm2 was made on the lateral wall of the maxillary sinus. After elevation of the Schneiderian membrane, the xenograft was used for bone grafting. The MSFE was possible with a minimum-sized window in 47 of 49 cases. For the remaining 2 cases, MSFE with a minimum-sized window was failed. In one case, it was expanded to be more than 30 mm2 to repair the membrane perforation. In another case, MSFE was performed by forming two minimum-sized windows. Post-operative bleeding after MSFE occurred in one anticoagulant-treated patient. There was no failed implant during the follow-up period (mean 22 months). A minimally invasive lateral approach through a small circular window with a diameter of 5 to 6 mm is a feasible and safe technique for MSFE with simultaneous implant placement.

Maxillary Sinus in Dental Implantology

Dental implants have significantly increased prosthetic options for the edentulous patient. Implant placement in the posterior maxilla may often be hampered due to anatomical limitations, inadequate height and width, and poor bone quality. After tooth extraction, three-dimensional physiological resorption and sinus expansion take place and reduce the volume of the alveolar ridge. The concomitant actions of alveolar atrophy and sinus pneumatization reconstruct the subantral alveolar segment into a low, shallow, and sloped ridge which is incapable to accommodate dental implants and bear the functional strains. Advanced maxillary resorption can be managed by several surgical options, the most popular of which is maxillary sinus floor elevation. The chapter discusses recent advancements in bone biology and biomechanics in the light of alveolar atrophy and the impact of anatomy on maxillary sinus floor elevation as a treatment modality for the partially or totally edentulous patient.

Influence of Anatomical Parameters on the Dimensions of the Subantral Space and Sinus Mucosa Thickening after Sinus Floor Elevation. A Retrospective Cone Beam Computed Tomography Study

Background: Various anatomical parameters might influence the surgical approach for maxillary sinus floor elevation. The objective of the present study was to retrospectively evaluate the influence of anatomical parameters on the dimensions of the subantral space and of the sinus mucosa thickening after sinus floor elevation. Material and Methods: Seventy-eight maxillary sinuses in sixty-five patients were evaluated on cone beam computed tomographies taken before surgery and after one week (t1w) and nine months (t9m). Several parameters such as the distance XF between an axis parallel to the base of the nose (X-axes) and the sinus floor (F) were correlated with the height gain (IF) at t1w and t9m and the post-surgical edema. Results: A weak significant positive correlation was observed between height gain vs. sinus height of interest (XF), the balcony, and the sinus floor angle. The post-surgical edema was influenced by the initial mucosa thickness and the xenograft used. Conclusions: Various parameters might affect height gain and sinus mucosa thickening after sinus floor elevation. The height of interest, the balcony, and the sinus floor angle showed significant correlations with height gain. The initial thickness of the mucosa and the biomaterial used influenced the post-surgical edema.