Fixation of Flowable Composite Resin Within Crossing Sutures for the Closure of Oroantral Communications: Two Clinical Cases and Literature Review

<b>Background:</b> Oroantral communications (OACs) are pathological openings between the oral cavity and the maxillary sinus, often resulting from dental extractions. If not treated promptly, they may lead to sinus infections and persistent oroantral fistulas (OAFs). <b>Objective:</b> This report aims to present a minimally invasive technique for the closure of OACs using flowable composite resin stabilized within a network of crossing sutures and to assess its clinical efficacy. <b>Case Descriptions:</b> Two male patients, aged 27 and 31, presented with OACs measuring 8 mm and 6 mm in diameter following maxillary molar extractions. Both cases were managed within 24-48 h postextraction. <b>Intervention:</b> Under local anesthesia, the extraction sockets were sutured using absorbable threads, creating a cross-matrix over the alveolus. Flowable composite resin was then applied into and over this suture network to form a sealing layer. The material was light-cured, and a secondary application was performed following socket curettage to promote stable blood clot formation. In this technique, the flowable composite is mechanically stabilized within the network of crossing sutures, which enhances the retention of the material, ensures effective sealing of the OAC, and supports a more predictable and secured healing process. <b>Outcomes:</b> In both cases, healing was uneventful, with complete closure of the OAC and no signs of sinusitis or fistula formation. Follow-up at 8 and 9 months confirmed successful mucosal healing and radiographic bone regeneration. <b>Conclusion:</b> The fixation of flowable composite within a suture matrix offers a novel, cost-effective, and reproducible technique for the immediate closure of small-to-moderate OACs. This approach enhances mechanical stability, improves sealing, and facilitates predictable healing while avoiding more invasive surgical interventions.