Biomechanical Analysis of Angled Abutments in the Anterior Maxilla: Impact of Bone Quality and Loading Conditions...

This in vitro study utilized three-dimensional (3D) finite element analysis (FEA) to investigate the stress distribution around dental implants in the anterior maxilla, focusing on the interplay between 15° angled abutments, bone quality (D1-D4), and loading conditions (axial and oblique).

Anatomically accurate 3D models of the anterior maxilla, a titanium Internal-Hex implant system (Touareg^TM(S), Adin Dental Implants, Chile), a 15° angled abutment, and a porcelain-fused-to-metal crown were developed using cone-beam computed tomographic (CBCT) scans and CATIA V5 software (Dassault Systèms, Vélizy-Villacoublay, France) and then analyzed in ANSYS Workbench (ANSYS Inc., Canonsburg, Pennsylvania, USA). Four bone types (D1-D4) were modeled with varying cortical and cancellous proportions. Axial (178 N) and oblique (100 N at 120°) loads were applied to eight models, and the stress and strain distributions were evaluated at the implant-bone and implant-abutment interfaces using tetrahedral elements. Mesh convergence ensured computational accuracy, and the material properties reflected clinical data.

Axial loading showed uniform stress at the implant neck, with cortical bone stress increasing from 12.023 MPa (D1) to 26.438 MPa (D4) and implant stress increasing from 67.319 MPa to 72.291 MPa. Oblique loading amplified stress asymmetrically, with cortical bone stress increasing from 20.005 to 30.704 MPa and implant stress from 97.910 to 102.458 MPa. D3 and D4 exhibit significantly higher stresses, particularly under oblique loading.

Bone quality and loading type critically influenced stress distribution. The stresses were higher in the D3 and D4 bones under oblique loading. Bone D1 and D2 provided robust support, whereas bones D3 and D4 required enhanced implant designs or augmentation. The 15° angled abutment increased stress, necessitating careful prosthetic planning to ensure biomechanical stability and esthetic outcomes in anterior maxillary implant dentistry.