This document discusses corrosion of biomaterials used in dentistry. It outlines the development of dental implants from ancient times to modern materials like metals, ceramics, and composites. Corrosion in biomaterials depends on the material properties and environmental factors like pH, temperature, and load exposure from use in the mouth. The key biomaterials discussed are metal alloys, resin composites, and ceramics, outlining the corrosion mechanisms for each in the oral cavity and importance of material selection and design to prevent corrosion.

1. Corrosion of
Biomaterials in
dentistry
MSE 531: CORROSION
SIDDHESH R. SAWANT

2. Outline
• Development of implants
• Biocompatibility
• Properties of biomaterials
• Biomaterials for implants
• Corrosion in biomaterials
• Conclusion

3. Development of Implants
• Implants in dentistry date back to Egyptian era and
traces of use found in South Central American cultures
• In 16th and 17th century implants were made of gold
and stone
• Early 20th century flourished use of implants made of
gold, stainless steel and cobalt alloy

4. Biocompatibility
• Interaction between biomaterials and living organisms
• Depends on material properties, tissue and external factors
• The dentistry implants are constantly exposed to different temperature
and pressure conditions
• Constant contact with different fluids of varying pH
• pH value of human saliva 5.2 to 7.8

5. Properties of Biomaterials
• The materials selected should have high modulus of elasticity
• They should have high tensile and compressive strengths
• They should have high yield strength and fatigue strength to avoid brittle fracture under cyclic
loading
• Minimum ductility of 8% required for dental implants

6. Biomaterials for Implants

7. Metal alloys corrosion
• Depends on type of metal used and environment it is exposed
• Oxidation and reduction reactions result into corrosion
• Galvanic type corrosion is observed in regions where two metals with different electrode potential
come in contact in presence of an electrolyte
• Crevicular corrosion occurs if there is crack in the metal surface

8. Pourbaix diagram
Pourbaix diagram for immune metal (gold) Pourbaix diagram for passive element
(titanium)

9. Potential vs Current density
Potential vs current density for some biomaterials

10. Corrosion of resin based composites
• Modern dentistry uses implants made from composites
• Due to external loads it may result in matrix deterioration, microcracking, interfacial debonding
• Usually biotribocorrosion is the cause of material degradation in composites

11. Corrosion in ceramics
• Ceramics are good material choice for dental implants when used in form of alloy.
• Corrosion affects the dental ceramics at the interface lines creating small holes
• Zirconia based ceramic is a common material for dentistry implants
• Zirconia is sensitive to stress corrosion because of the change in crystalline phase

12. Conclusion
• To prevent corrosion of biomaterials in dentistry, it is important to recognize the factors
causing these corrosion types
• Same material type usage should be given emphasis for the same patient
• Materials with similar corroding potential value should be given preference with the idea of
biocompatibility
• Measures should be taken to keep materials electrically insulated