Comparison of stresses in monoblock tilted implants and conventional angled multiunit abutment-implant connection systems in the all-on-four procedure

Abstract

Background The All-on-four dental implant method is an implantology method designed to provide a comfortable prosthetic treatment option by avoiding advanced surgical procedures. This research aims to compare and evaluate the stress and tension values in conventional angled multiunit abutment-implant connection systems and monoblock dental implants used in the all-on-four procedure with finite element analysis. Methods Two master models were created by placing four implants connected to multiunit abutments (group A) in the interforaminal region of a completely edentulous mandible and four monoblock implants (group B) in the same region of another completely edentulous mandible. Group A implants were classified according to their diameter as follows: 3.5 mm (M1A), 4.0 mm (M2A), and 4.5 mm (M3A). Similarly, group B implants were classified as M1B, M2B, and M3B. In the six models rehabilitated with acrylic fixed prostheses, a 100 N force was applied to the anterior implant region, and a 250 N force was applied to the posterior cantilever in both axial and 30° oblique directions. Von Mises stresses were analyzed in the bone and implant regions of all models. Results M1A and M1B, M2A and M2B, and M3A and M3B were compared with each other under axial and oblique forces. The maximum Von Mises stresses in the bone around implants and the prosthesis screws, and the maximum and minimum principal stresses in the cortical and trabecular bone in group A models were significantly higher than those in group B models. Conclusions In monoblock implant systems under axial and oblique forces, higher stress is accumulated in the bone, prosthesis screw and implant compared to multiunit abutment-implant connection systems.

Does a sloped neck implant design facilitate All-on-4 surgeries? A three-dimensional finite element analysis

“…The number of nodes and elements used in FEA studies is directly related to the sensitivity of those studies. In the present case, the number of nodes and elements was sufficient to maximize sensitivity, in agreement with previous studies [22,24,30,31]. The functional and parafunctional loads produced by mastication are transferred to implants and surrounding tissues through the prosthetic components in implantsupported restorations.…”

“…One-piece tilted implants with a standing multiunit abutment have been designed to prevent complications that may occur in the abutment-implant connection areas. Zincir and Parlar compared this implant design with the conventional two-part implant-abutment connection and reported that although the biomechanical stress values in single-piece implants are higher, one-piece tilted implants can be used within biomechanical limits [31].…”