Dental Implantation

Cho Young Kuen

The different stress distribution between normal and abnormal ratio of crown

Introductory

The most frequent surgical procedure performed upon humans is dental extraction.

The most frequently employed prosthesis is the complete or partial denture. (Cranin, Worthington, 1988)

Introductory

Analyzing force transfer at the bone-implant interface is an essential step in the overall analysis of loading.

Both implant and bone should be stressed within a certain range for physiologic homeostasis.

(Static, dynamic and fatigue behaviors of dental implant using finite element method)

Introductory

3 steps for implantation

1. Cut section

2. Implant the fixture

3. Implant the others

(abutment, metal frame, occlusal material)

(Http://catalog.nucleusinc.com)

Introductory Assumptions

1. The crown ratio of the dente is not always same in every dental implantation.

2. If trabecula bone density is not enough for implatation, how stress distribution is occurred?

(Http://catalog.nucleusinc.com)

Biomaterials

Parts Materials Young’s modulus (MPa)

Poisson’s ratio

Crown Porcelain 68900 0.28

Implant Titanium 110000 0.35

Cortical Bone Cortical Bone

13400 0.30

Spongy Bone Spongy Bone

1370 0.30

Simulation purpose

Simulate for physical reaction on same structure but different ratio of crown

Case 1. Normal Case 2. Abnormal ( 1.5 times ) Case 3. Abnormal ( 2.0 times )

Why do abnormal?

1. It’s caused by position of transplant. (e.g. a cuspid, a grinder)

2. Jawbone is going down (then turn it black).

Meshing

Meshing by Hypermesh

1.Crown

2.Implant

3.Cortical outer

4.Spongy

5.Cortical inner

Analysis

Loading phase FX : -17.1 N FY : -114.6 N FZ : 23.4 N FT : 118.2 N

Analyze by ANSYS10.0 Material properties

Result

Normal

Result

Abnormal ( 1.5 times )

Result

Abnormal ( 2.0 times )

Result

I make a path to measure the stress by 90 nodes on the contact surface

between cortical outer bone and implant.

Result

Discussion

• There are certain parts the maximum stress is occurred.

• Some parts have more stress to take overload without overall failure.

• It’s means that the life of implant can be longer to modify the shape or to fill in the trabecula bone.

Further study

• We assumed that the crown ratio is different between each dente, however, it can be make up by shape of crown.

• So we need to analyze using various types of crown.

Any Questions?

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