Removal of Inflammatory Tissue/Product by Sinus Membrane Puncturing during Lateral Sinus Augmentation in Asymptomatic Patients with Severely Opacified Sinuses: A Case Series

It is generally recommended that severe sinus membrane (SM) thickening should be treated prior to maxillary sinus augmentation (MSA), but during lateral MSA, inflammatory tissue/product may be removed by puncturing the SM. The present case report demonstrates surgical experience of lateral MSA with simultaneous inflammatory tissue/product removal for sinuses with severe opacification. In three patients requiring dental implant placement in the posterior maxilla, severe SM thickening was observed, but they were asymptomatic. The SM was gently elevated, followed by puncturing the SM, removing inflammatory tissue via the punctured site, draining, and thorough saline irrigation. Then, bone grafting and implant placement were performed with extra care not to spread bone substitute material into the punctured area. The postoperative pain following this procedure was more severe as compared to conventional MSA. Nasal bleeding was reported for 2–3 days. All implants were successfully integrated and demonstrated adequate function. Tissue samples retrieved during the surgery showed advanced inflammatory cell infiltration. The follow-up cone-beam computed tomographic scans revealed a significant reduction in SM thickening. In conclusion, inflammatory tissue/product removal by puncturing the SM can be applied during lateral MSA. However, more data should be needed due to the empirical nature of the present outcomes.

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.

Stiffness Regulates the Morphology, Adhesion, Proliferation, and Osteogenic Differentiation of Maxillary Schneiderian Sinus Membrane-Derived Stem Cells

Recent studies, which aim to optimize maxillary sinus augmentation, have paid significant attention exploring osteogenic potential of maxillary Schneiderian sinus membrane-derived cells (MSSM-derived cells). However, it remains unclear that how MSSM-derived cells could respond to niche’s biomechanical properties. Herein, this study investigated the possible effects of substrate stiffness on rMSSM-derived stem cell fate. Initially, rMSSM-derived stem cells with multiple differentiation potential were successfully obtained. We then fabricated polyacrylamide substrates with varied stiffness ranging from 13 to 68 kPa to modulate the mechanical environment of rMSSM-derived stem cells. A larger cell spreading area and increased proliferation of rMSSM-derived stem cells were found on the stiffer substrates. Similarly, cells became more adhesive as their stiffness increased. Furthermore, the higher stiffness facilitated osteogenic differentiation of rMSSM-derived stem cells. Overall, our results indicated that increase in stiffness could mediate behaviors of rMSSM-derived stem cells, which may serve as a guide in future research to design novel biomaterials for maxillary sinus augmentation.