Evaluation of design parameters of dental implant shape, diameter and length on stress distribution: a finite element analysis

Abstract

The aim was to evaluate the design parameters of dental implants shape, diameter and length on stress distribution by finite element analysis (FEA).The objectives of the study was to compare the influence of stress distribution in the implants of screw-vent tapered and parallel design by varying the implant diameter with a standard implant length. Six dental implant models have been simulated three-dimensionally. The influence of diameter and length on stress distribution was evaluated by Group I: for screw-vent tapered design (Zimmer Dental Implant Carlsbad, CA, USA) (1) Dental implant model with diameter 3.7 mm and length 13 mm. (2) Dental implant model with diameter 4.1 mm and length 13 mm. (3) Dental implant model with diameter 4.7 mm and length 13 mm. Group II: for parallel design (Zimmer Dental Implant Carlsbad, CA, USA) (4) Dental implant model with diameter 3.7 mm and length 13 mm. (5) Dental implant model with diameter 4.1 mm and length 13 mm. (6) Dental implant model with diameter 4.7 mm and length 13 mm. The 3-D model of the implant was created in the pro-e wildfire 4.0 software by giving various commands. This model was imported to the ANSYS software through IGES (initial graphic exchange specification) file for further analysis. All six models were loaded with a force of 17.1, 114.6 and 23.4 N in a lingual, an axial and disto-mesial direction respectively, simulating average masticatory force in a natural oblique direction, to analyze the stress distribution on these implants. The increase in implant diameter in Group I and Group II from 3.7 to 4.1 mm and from 4.1 to 4.7 mm with constant 13 mm length for screw-vent tapered and parallel design implant resulted in a reduction in maximum value of Von Mises stress in the bone surrounding the implant was statistically significant at 5% level done by student "t" test. The overall maximum value of Von Mises stress was decreased in parallel design implant diameter of 4.7 mm with constant length of 13 mm when compared to screw-vent tapered design implant samples. The results of the FEA computation depend on many individual factors including material properties, boundary conditions interface definition and also on the overall approach to the model. The results depicted that the tapered shape implant design exhibited higher stress levels in bone than the parallel shaped implant design which seemed to be distributing stresses more evenly. The application of a 3-D model simulation with the non-symmetric loading by the masticatory force on a dental implant resulted in a more satisfactory modeling of "clinical reality" than that achieved with 2-D models used in other studies.

Keywords: Finite element analysis; Optical comparator; Von Mises stress.

Figures

Fig. 1

Optical comparator

Fig. 2

Screw-vent tapered design dental implant sample A—diameter 3.7 mm, length 13 mm

Fig. 3

Parallel design dental implant Sample D—diameter 3.7 mm, length 13 mm

Fig. 4

Finite element model of dental implant with bone containing nodes and elements. Sample A—diameter 3.7 mm, Length 13 mm

Fig. 5

Different types of structural forces applied to the dental implant. A indicates force acting in axial direction = 114.6 N. B indicates force acting in lingual direction = 17.1 N. C indicates force acting in disto-mesial direction = 23.4 N

Fig. 6

Equivalent stress developed on dental implant after analyzing in Sample A. Maximum stress occurring region on dental implant Sample A

Fig. 7

Equivalent stress developed on dental implant after analyzing in Sample D. Maximum stress occurring region on dental implant Sample D

Fig. 8

Bar diagram Von Mises stress in Group I implants

Fig. 9

Bar diagram Von Mises stress in Group II implants