Histological and Radiological Evaluation of Collagenic Porcine Graft vs Collagen-enriched Bovine-derived Graft in Transcrestal Sinus Elevation. A Randomized Prospective, Controlled Study.

Transcrestal sinus floor elevation (tSFE) is an established technique for vertically augmenting bone in the edentulous posterior maxilla, offering a less invasive alternative to the lateral approach.

Among the various bone substitutes used in transcrestal sinus augmentation, one widely adopted option is the collagen-enriched bovine-derived bone substitute. This material is composed predominantly of deproteinized bovine bone granules combined with a minor fraction of highly purified porcine collagen. The addition of collagen improves the handling properties and moldability of the graft, facilitating its clinical application.

An alternative approach involves the use of porcine graft, which, due to its deantigenation process, results to be completely enbibed with its native collagen. This was demonstrated to allow a better regeneration due to its angiogenic and osteogenic potential The primary objective of the present study is to perform a histological evaluation of the quality of bone regeneration following the placement of a graft material during transcrestal sinus floor elevation in cases of severely resorbed posterior maxilla. Specifically, the analysis will quantify the relative proportions of native bone, newly formed bone, connective tissue, and residual graft material within the augmented area. The secondary objectives are to assess, through radiographic analysis, the volumetric changes of the grafted area over time-including the rate of graft material resorption or shrinkage-and to evaluate the implant survival rate associated with this regenerative approach.

Materials and Methods: The study was designed as a prospective, randomized, controlled clinical trial. All patients requiring an implant-supported restoration in the posterior maxilla with a residual bone height of less than 4 mm beneath the maxillary sinus floor were eligible for the study. A minimum sample of 12.2 participants for each group (24.4 participants in total) was required to detect significant differences between the two groups Preoperatively, all patients will undergo a comprehensive clinical and radiographic evaluation. This includes a full periodontal examination, assessment of occlusal relationships, and evaluation of the prosthetic space. Cone Beam Computed Tomography (CBCT) scans and digital dental impressions will be obtained. The resulting Standard Tessellation Language (STL) and Digital Imaging and Communications in Medicine (DICOM) files will be matched and integrated into a digital workflow for virtual planning using dedicated software (RealGUIDE, 3DIEMME, Cantù, Italy).

Following the administration of local anesthesia (2% mepivacaine HCl with 1:100,000 epinephrine), a minimally invasive full-thickness envelope flap will be elevated to expose the surgical site. Access to the sinus cavity will be achieved via a crestal approach. Initial drilling will be performed using a 2 mm drill until contact with the cortical bone of the sinus floor. Subsequently, osteotomic screws of increasing diameters (typically 3.5 and 4.0 mm) will be used to complete the crestal antrostomy. A preliminary detachment of the Schneiderian membrane will be performed using specially designed microelevators (Dajelevators, Merighi Umberto, Valsamoggia, Italy). After checking membrane integrity using the Valsalva maneuver, the selected bone graft material will be inserted in small increments and gently compacted using a plugger to further elevate the sinus membrane from the floor and the lateral and medial walls of the sinus cavity. Collagenic porcine bone graft (MP3, Osteobiol, Giaveno, Italy) will be inserted in test group, while a collagen-enriched, bovine-derived bone substitute (Bio-Oss Collagen, Geistlich, Wolhusen, Switzerland) will be used in the control group. Once a satisfactory elevation will be achieved-defined as a total height of at least 10 mm from the crestal bone level to the elevated membrane position, as verified by intraoperative periapical radiographs-the crestal access will be sealed with a final increment of graft material.