BIOMECHANICAL BEHAVIOR OF THE HYBRID ALL-ON-4 TECHNIQUE WITH SMOOTH ZYGOMATIC IMPLANTS AND EXTRA-LONG IMPLANTS WITH TRANSNASAL ANCHORAGE: A FINITE ELEMENT ANALYSIS

Abstract

The rehabilitation of patients with severely atrophic maxilla is a challenge and the hybrid all-on-4 technique emerges as an alternative for the treatment of these patients. This study aimed to evaluate the mechanical behavior of the rehabilitation of a severely atrophic total edentulous maxilla using smooth zygomatic implants and extra-long transnasal implants. Finite element analysis was conducted in the following configuration: two 3.75x45 mm Zygoma-S® implants installed using the sinus duct technique. 60 and 52 degree Mini Conical Abutment components with 1.5 mm gingival height were positioned in the regions of teeth 16 and 26 respectively. Two Helix Long GM® 3.75x20 mm and Components Mini Straight Conical Pillar with gingival height 1.5 mm were installed in the anterior region using the transnasal technique. A prosthetic bar was shaped and retained by 4 screws with a 12 mm cantilever. The peak stresses on the bone, implant, prosthetic component, and screws were below the strength limits of the materials. In addition, higher stresses were found in the zygomatic implants. Conversely, higher tensions were found in the thread region of the prosthetic components associated with the extra-long implants. The present study revealed that the rehabilitation of severely atrophic maxillae by the hybrid all-on-4 technique using two zygomatic implants and two extra-long implants with transnasal anchorage is biomechanically favorable and reliable.