Finite element analysis on preferable I‐bar clasp shape

Abstract

An I-bar clasp is one of the most popular direct retainers for distal-extension removable partial dentures. However, no adequate information is available on preferable shape as determined by biomechanics. This study aimed (1) to investigate, by finite element analysis (FEA), the dimensions and stress of I-bar clasps having the same stiffness, and (2) to estimate a mechanically preferable clasp design. Three-dimensional FEA models of I-bar clasps were created with vertical and horizontal straight sections connected by a curved section characterized by six parameters: thickness of the clasp tip, width of the clasp tip, radius of the curvature, horizontal distance between the base and the vertical axis, vertical dimension between the tip and the horizontal axis, and taper (change of width per unit length along the axis). Stress was calculated with a concentrated load of 5 N applied 2 mm from the tip of the clasp in the buccal direction. A thinner and wider clasp having an taper of 0.020-0.023 and radius of curvature of 2.75-3.00 showed less stress. The results suggest that such a shape might be the preferable I-bar clasp shape as biomechanical viewpoint.

Retention and Fatigue Resistance of Peek and Acetal Thermoplastic Resin Clasps

“…Polyetheretherketone (PEEK) is a synthetic, tooth colored polymeric material that has been used as a biomaterial in orthopedics for many years with observed mechanical properties, and adequate mechanical stability to justify the basic requirements in the restorative field as showed by recent studies (14,15) . A few studies have reported on the adequate retentive forces required for clasps retention (16,17) . One study stated that 3 to 7.5 N is the retentive force required for adequate retention and functioning of PRDPs, while another study found that 5 N could give an acceptable degree of retention (18) .…”

Finite element analysis of stress distribution on modified retentive tips of bar clasp

“…Recent studies have shown FEA to be a suitable method for the evaluation of complex geometric models (Sato et al 1995(Sato et al , 1999(Sato et al , 2000(Sato et al , 2001a(Sato et al , 2001b. Previous studies have simulated the application of 5 N loads to RDP clasps (Yuasa et al 1990;Sato et al 1995Sato et al , 2000Sato et al , 2001aSato et al , 2001b.…”

“…Bar clasps with a wide range of dimensions are used in clinical applications, and Sato et al (2000Sato et al ( , 2001aSato et al ( , 2001b stated that the ideal bar clasp shape is still unknown. Their studies have shown bar clasp thickness and tapering to be the critical parameters that have a great effect on stress and flexibility, finding specifically that a uniformly tapered bar clasp arm decreases stress concentrations.…”

“…This movement causes deformation and stress, resulting in damage to periodontal tissue. Although researchers have focused on the principles of biomechanics in planning clasps, very few studies have examined the distribution of stress in different types of denture clasps (Sato et al 1995(Sato et al , 1999(Sato et al , 2000(Sato et al , 2001a(Sato et al , 2001b. The aim of this study is to evaluate the effects of modified retentive tips of bar clasps constructed from Co -Cr, Ti and Type IV Au alloys on stress distribution using 3D finite element analysis (FEA).…”

Virtual Bone Augmentation in Atrophic Mandible to Assess Optimal Implant-Prosthetic Rehabilitation—A Finite Element Study

“…Young's Modulus (MPa) Poisson Coefficient Cortical bone [15][16][17] 13,700 0.3 Cancellous bone [17,18] 1370 0.3 Gingiva [19] 19.6 0.3 [21] 69 0.45 Ceramic [22] 140,000 0.28 Ti-6Al-4V [23] 110,000 0.35 Cement [24] 10,760 0.35 Figure 3. Complete mandible assembly in the simulation environment with applied forces corresponding to pterygoid muscles (P) and the masseter muscles (M) and restrictions at the temporomandibular joint surfaces.…”