What do we know about the use of new metals to build prosthetics on teeth and implants? Could a base alloy like cobalt-chromium be an option? What effects does such an alloy have on the patient?


Partwork 1 published
Partwork 2 published
Partwork 2 submitted
Partwork 4 published


Project thesis

Cobalt-Chromium alloys in fixed prosthodontics

Institute of Postgraduate Dental Education'r role in the project

Project Leader


Project startup




NIOM - Nordic Institute of Dental Material



Futurum, Region Jönköpings län

Sveriges Tandläkarförbund

Folktandvården i Sörmland

Sylvan Foundation


Project leader

Maria Kassapidou, consultant orthodontist, Department for Oral Prosthetics, Institute for Postgraduate Dental Education, Region Jönköping County. Doctoral student, Institute for Odontology, Sahlgrenska Academy, Gothenburg University.

Project Members

Lars Hjalmarsson, consultant orthodontist, DDS, lecuturer, Institute for Odontology, Sahlgrenska akademin, Gothenburg University.
Head of Specialist Dental Care at the Public Dental Healthcare Services in Sörmland, AB.

Carina B Johansson, Professor Emeritus, Institute for Odontology, Sahlgrenska Academy, Gothenburg University.

Ann Wennerberg, consultant orthodontist, Professor in Oral Prosthetics, Institute for Odontology, Sahlgrenska Academy, Gothenburg University.

Victoria Franke Stenport, consultant orthodontist, Professor of Oral Prosthetics, Institute for Odontology, Sahlgrenska Academy, Gothenburg University.

Petra Hammarström Johansson, laboratory assistant, Institute for Odontology, Sahlgrenska Academy, Gothenburg University.

Else A Morisbak, senior engineer, Bioengineer MSc, Nordic Institute of Dental Material.

Previous or related articles and publications

Cobalt-chromium alloys in fixed prosthodontics in Sweden

Cobalt–chromium alloys fabricated with four different techniques: Ion release, toxicity of released elements and surface roughness

Purpose and goal

When you have lost one or more teeth, it is common to get artificial teeth made of porcelain. Porcelain itself is not strong enough to withstand the forces at work in the mouth. Therefore, there must be a metal substructure to which the porcelain bonds.

The materials we have in our mouths should be resistant to stress (when chewing) and an acidic environment (when we put food in our mouths) but should also be tissue-friendly (biocompatible).

The overall aim of the project is to increase knowledge about materials used in fixed prosthetics, i.e. on teeth and implants. More specifically, the project wants to investigate the most commonly reported cobalt-chromium alloys (Co-Cr) and compare with titanium materials with respect to mechanical properties and biological aspects.


New materials and methods are quickly implemented in dentistry. Also, materials are introduced before the older materials have been properly evaluated. Knowledge of these materials and their production techniques in dentistry is currently deficient and this can affect patient safety.

Gold has long been used as a substructure for porcelain teeth, but due to high gold prices, it has been replaced by base alloys, such as Co-Cr. One of the advantages of Co-Cr, in relation to gold, is its good mechanical properties.

However, the biocompatibility in relation to other materials, such as titanium, is questionable. Studies have mentioned risks such as ion release from various metals which can be a contributing cause of negative biological reactions in the tissue.

One such test that simulates this is the so-called ion release tests, where advanced methods measure the content of ions released from a material into an artificial saliva.

In the project's first study, which was a questionnaire study aimed at all dental technicians in Sweden, it was found that more than 30 different Co-Cr alloys are used in fixed prosthetics. The difference between them is that they are produced in different ways and have different compositions. We know very little about how these materials behave and so it is of the utmost importance from a patient safety aspect to investigate any differences between the various alloys.

In patients with orthopedic hip joint implants made of Co-Cr and titanium, it has been possible to see elevated levels of metal ions. Increased levels of metal ions or metal particles in these patients have been mentioned as being able to affect the lifespan of the hip joint implant. However, the possible negative effects of ion release in humans are unknown.


Basic methods to investigate and evaluate any differences between different materials used in the mouth are so-called screening tests. They include studies in a laboratory environment, for example cell viability tests.

Such a test looks at what percentage of living cells are present after they have been exposed to a material.

At the same time, it is also interesting to investigate what happens to the ion content in the saliva when different materials are combined, for example titanium and Co-Cr, during an implant treatment.


Increased knowledge about materials that are widely used in the mouth will have a positive effect on the safety of patients.

Futhermore, it could lead to the use of cheaper and more sustainable materials, which can benefit the patiend and would be better for the environment.