A Histological Assessment of Bone Augmentation of a Knife-Edge Alveolar Ridge by the Umbrella-Screw Tent Technique Using a Xenograft Compound with Polynucleotide-Hyaluronic Acid—A Case Report

Objectives: Horizontal ridge augmentation remains a clinical challenge due to limitations in terms of spatial maintenance, graft stability and predictability of new bone formation. The umbrella-screw tent technique provides mechanical stability for particulate grafts, while adjuvants such as hyaluronic acid (HA) and polynucleotides (PN) may enhance biological remodeling. Evidence for this compound in implant-related bone augmentation is still scarce. Material and methods: In a single patient with a knife-edge alveolar ridge, augmentation was performed in regions 34 to 36 using the umbrella-screw tent technique. The defect was grafted with deproteinized bovine bone mineral (DBBM) mixed with hyaluronic acid (HA) and polynucleotides (PN), supplemented with platelet-rich fibrin (PFR) and covered with a resorbable collagen membrane. After six months, two implants were installed, and a biopsy was obtained by trepanation for histological and histomorphometric analysis. Results: Healing occurred without compromise, with no signs of infection or graft exposure. Horizontal bone gain averaged 4.5 mm, corresponding to a relative Target Performance Index (TPI-h) of 75%. Histomorphometric analysis revealed a total mineralized fraction of 76.4%, consisting of 36.1% newly formed bone and 40.3% residual DBBM particles. The xenogeneic granules were completely integrated into mature bone, with no signs of inflammation or foreign body reaction. Conclusion: The case report illustrates that the combination of DBBM with HA and PN, stabilized by the umbrella-screw tent technique, can lead to significant new bone formation and favorable graft integration. Although limited by its single-case design, the case report provides preliminary insights into the synergistic potential of HA and PN as biological enhancers in bone augmentation, warranting further controlled studies.