All surgeries were performed by the same surgeon, preceded by local anaesthesia (Articaine 4 mg/mL + 0.01 mg/L Artinibsa™, Barcelona, Spain), followed by an incision on the maxillary crest, with two accessory vertical incisions. The detachment and elevation of the flap were performed in total thickness exposing the lateral bone wall of the maxillary sinus [10 (link)].
A lateral oval shape osteotomy was performed with a piezoelectric instrument (NSK VarioSurg™, Tokyo, Japan) or with a spherical diamond tip (NSK™, Tokyo, Japan). The Schneider’s membrane was carefully lifted through proper curettes (Hu-Friedy®, Chicago, IL, USA). Following the Schneider’s membrane elevation, a randomised opaque sealed sterilized envelope containing the assignment code was opened: (1). test with a cortico-medullar porcine xenograft Osteobiol Mp3® (Tecnoss™, Torino, Italy, granulometry between 600–1000 µm with 10% collagen of type I and III) [29 (link),30 (link)]; and (2). control with harvest of intraoral autologous bone graft.
Autologous bone was collected from mandible body or mental symphysis and particulate with a bone mill (ACE™, Pearl St. Brockton, MA, USA). Sinus cavities were filled up to the desired height. The lateral osteotomy was then covered with a collagen membrane (Osteobiol by Tecnoss™, Torino, Italy) and the flaps were sutured with polyamide 4.0 (Supramida™, B Braun, Melsungen, Germany).
The postoperative protocol comprised: Amoxicillin 1 g for a week; chlorhexidine gel 0.2% for 2 weeks; Ibuprofen 400 mg, if pain; soft diet for 2 weeks; ice application within the first 48 h. Additionally, the patients should avoid blowing their noses and using straws; sneezing with their mouth opened; and using any superior removable prosthesis. The sutures were removed after 10 days.
Six months after surgical intervention, a new computer tomography (CT) was made, patients were inquired about treatment preferences and the second surgical stage was performed by the same surgeon under local anaesthesia administration, while the incision and the elevation of the flap were performed in total thickness. The bone collection was performed on both regenerated sides before the use of the first drill of the implant system. The procedure was carried on trans alveolar in the implant sites, with a trephine with an internal diameter of 2 mm and a total diameter of 3 mm (Hager & Meisinger™, Neuss, Germany). Samples were immediately immersed in flasks containing buffered formaldehyde. After bone sample collection, submerged dental implants (Osseo Speed TX™, Astra Tech™, Mölndal, Sweden) were placed following the manufacturer’s recommendations. The flaps were sutured with polyamide 4.0 suture (Supramida™, B Braun™, Melsungen, Germany). After ten days, the sutures were removed, and eventual postoperative complications were clinically evaluated and registered.