Finite element analysis of welded titanium bar and poly ether ether ketone bar in maxillary full arch splinted interim prosthesis

Abstract

Full arch fixed provisional restorations are prone to fracture during function for several reasons. Those types of fractures during the healing period eliminate the cross-arch stabilization and disrupt stress distribution patterns. FEA (Finite Element Analysis) study was carried out using edentulous maxillary models where implants and other components were represented in three dimensional (3D) geometric models. Two 3D FEA models with six implants were used. Model TB: the implants were splinted with welded titanium bar; Model PB: the implants were splinted with PEEK (Poly Ether Ether Ketone) bar. An interim full arch PMMA (Poly methyl methacrylate) prosthesis was virtually designed for both models. Both models were subjected to vertical and oblique forces with a single force magnitude of 100 N. The amount of maximum equivalent Von-Mises stresses was calculated at the cervical part of the bone cylinder (marginal bone) and both frameworks. Under bilateral vertical loading, stresses were found to be comparable at the marginal bone between titanium and PEEK splinting. The PEEK framework had better and lower stress distribution than the titanium. While under unilateral oblique forces PEEK had better mechanical response on the marginal bone. And PEEK framework itself showed higher stresses than the titanium. The behavior of PEEK and Titanium splints are comparable under the vertical bilateral load. On the contrary to the oblique load, where the stresses are higher within the PEEK splint that correspondingly transmit less stresses to the underlying structures. So, PEEK was found successful in regards to the pattern of stress distribution to both implants and marginal bone, but further studies are needed to confirm its effectiveness and broader applicability.

Fig. 1

Model designing; (a) bone cylinder, (b) implant, (c) multi-unit abutment, (d) temporary titanium sleeve, (e) implants splinted with titanium bar of 2 mm thickness titanium wire, (f) Implants splinted with PEEK bar of 3 mm thickness, (g) prosthetic superstructure designed using Exocad software to be in the form of full arch PMMA prosthesis. Image courtesy of Dr. Nermeen Ahmed Hassan, published under a CC BY open access license with permission.

Fig. 2

Model meshing. Image courtesy of Dr. Nermeen Ahmed Hassan, published under a CC BY open access license with permission.

Fig. 3

Load application; (a) application of bilateral vertical load of 200 on the central fossae premolar and the first molar (b) application of unilateral oblique load to the lingual inclines of the buccal cusps of the premolar and first molar with an angle of about 45 degrees to the vertical axis of the tooth. Image courtesy of Dr. Nermeen Ahmed Hassan, published under a CC BY open access license with permission.

Fig. 4

Stress distribution during the application of bilateral vertical load on (a) Marginal bone in Titanium model(TB), (b) Marginal bone in PEEK model(PB), (c) titanium wire, (d) PEEK framework. Image courtesy of Dr. Nermeen Ahmed Hassan, published under a CC BY open access license with permission.

Fig. 5

Stress distribution during the application of unilateral oblique load on (a) marginal bone in titanium model (TB), (b) marginal bone in PEEK model (PB), (c) titanium wire, (d) PEEK framework. Image courtesy of Dr. Nermeen Ahmed Hassan, published under a CC BY open access license with permission.

Fig. 6

Strain distribution during the application of bilateral vertical load on (a) marginal bone in titanium model (TB), (b) marginal bone in PEEK model (PB), strain distribution during the application of unilateral oblique load on (c) marginal bone in titanium model (TB), (d) marginal bone in PEEK model. Image courtesy of Dr. Nermeen Ahmed Hassan, published under a CC BY open access license with permission.