Topological Optimization of a Dental Prosthesis

Dipartimento di Ingegneria Meccanica e Aerospaziale

Prof. Massimiliano AVALLE Dr. Alessandro SCATTINA

Dr. Paolo C. PRIARONE Marco BELLANDA, MD

Topological Optimization of a Dental Prosthesis

2013 European Altair Technology Conference


2013 European Technology Conference

Aim of the bridge

– Fix the prosthesis attached to the mandibula

Introduction


2013 European Technology Conference Introduction

Mandibula model

(metal) bridge

Artificial gingiva


2013 European Technology Conference Introduction

Aim of the project

– The problem:

• excessive heigth and weight of the prostheses = patient’s discomfort

– The (possible) solution:

• To lighten the bridge by

– Using lightweight materials

– Applying optimization



Parametric optimization

– The shape is given, parameters like thickness, are changed to obtain the objective

Shape optimization

– The shape is changed to obtain the optimization

Topological optimization

– Only a volumetric constraint is given leaving the optimization algorithm free to find the optimal solution by removing useless material

Optimization methodologies



Minimum bridge width

Fixation points

– Usually 4 to 6 depending on the patient

Material Golden alloy

Chromium/cobalt alloy

Titanium alloys

Composites

Topological Optimization: problem definition

?



In biomedical applications, each product is personalized on the basis of the patient

Model definition

3D facets and tetrahedral elements reconstruction

CT scans



Simulation of the atrophy of the mandibula after damaged teeth removal

Model definition



3 analyzed cases

Control Volume Definition

Large control volume

Light control volume

Optimized control volume


2013 European Technology Conference Control Volume Definition



Optimized control volume

3 analyzed cases



Boundary conditions

– Boundary conditions are essential in the topological optimization

– Constraints: fixation points

– Loads: bite loads?


Main biting modes



Boundary conditions

– Loads: bite loads




Boundary conditions

– Loads: bite loads


Three different load cases have been examined:

Point loads

Pressure loads

Wrench equivalent load



Pressure loading mode

Topological optimization results





Point loading mode



Light control volume Light control volume



Additional volume constraint

Control Volume Definition

Fixed volume (red)

Study volume (blue)



Results with additional volume constraints


60% weight and volume reduction



Results with additional volume constraints


Von Mises Stress

Displacements


2013 European Technology Conference Conclusions

The topological optimization method implemented in OPTISTRUCT was efficiently applied to the improvement of a dental surgery prosthesis

The objective was to reduce the volume and weight of a dental bridge, usually a massive metal (gold or titanium) structure

The biggest problem is related to the loading mode: few and incomplete information are available, the different loading modes are only known as rough estimates

Another difficulty is related to the variability of the problem: each patient is a single different case, and should be treated as an individual optimization problem

Despite the difficulty a reduction of 60% in weight and volume was achieved: a verification by experimental tests (on a real patient) is being carried out.


Thank you for the attention

Topological Optimization of a Dental Prosthesis

2013 European Altair Technology Conference

Prof. Massimiliano AVALLE Dr. Alessandro SCATTINA

Dr. Paolo C. PRIARONE Marco BELLANDA, MD