Dental implants success rate is closely related to the materials, known as biomaterials, and designs used for these root-like structures. So, what are teeth implants made of?
There are many types of implant materials available today, and choosing the right one is critical for a successful treatment. An ideal dental implant material should be:
- Biocompatible (safe for the body)
- Strong and tough (able to handle chewing forces)
- Resistant to corrosion, wear, and fractures
To make the best choice, dentists need to have a thorough understanding of the latest implant materials, their design features, and their properties. This Blog explores the different materials used in generating dental implants.
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ToggleTypes of Implant Materials or Implant Biomaterials
Since the early days of dental implants, many different materials have been used to create them. Dental implants are usually made from one of three main types of materials:
- Metals (like titanium)
- Ceramics (like zirconia)
- Polymers (special types of plastics)
Metal Implants
Metals and their alloys are the most commonly used materials for making dental implants. These metals include titanium, titanium alloys, tantalum, stainless steel, cobalt-chromium alloy, gold alloys, vanadium, molybdenum, and nickel. Among these, titanium alloys are the most commonly used due to their excellent properties and biocompatibility.
Titanium: The Gold Standard for Dental Implants
Titanium and its alloys have a strong reputation for their long-term success in dental implants, making them the “gold standard” material. While metals like gold, stainless steel, and cobalt-chromium were tried in the past, they often caused negative tissue reactions and had low success rates. As a result, these materials are no longer used in modern dental implants.
Metal Implants (Titanium and Alloys) Failure Conditions
- Mechanical Failures:
- Metal Fatigue: Repeated chewing forces cause small cracks, eventually leading to fractures.
- Bending Forces: Bone loss increases stress, causing cracks in the implant threads.
- Corrosion Issues:
- Surface Corrosion: Releases metal ions that can trigger allergic reactions.
- Galvanic Corrosion: Reaction with other metals (e.g., crowns) increases tissue toxicity and bone loss.
- Other Factors:
- Hydrogen Brittleness: Absorption of hydrogen weakens the metal, making it brittle.
- Poor Fit or Design Flaws: Increases stress and the risk of fracture.
Exploring the Different Types of Metal Implants
Type of Metal Implant |
|
Pure Titanium (CpTi)
| Description: A blend of titanium and oxygen, with small amounts of carbon, nitrogen, and iron. Available in four grades (Grade I to IV). Ideal for dental implants.
Benefits Highly biocompatible, lightweight, corrosion-resistant, and strong. Bonds well with bone, Long-term success rate.
Disadvantages: Can be weaker compared to alloys, Potential for allergic reactions (though rare)
|
Titanium Alloys
| Description: Titanium combined with aluminum (6%) and vanadium (4%). The most common type is the alpha-beta (α-β) alloy. Heat treatment improves strength. Commonly used in dental implants.
Benefits: Stronger than pure titanium. Excellent fatigue strength and durability.
Disadvantages: Aluminum and vanadium may raise biocompatibility concerns in rare cases.
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Titanium-Zirconium (Ti-Zr) Alloys (e.g., Roxolid)
| Description: A titanium-zirconium alloy developed for narrow-diameter implants. Developed by Straumann. Suitable for smaller implants.
Benefits: 50% stronger than pure titanium, with better fatigue strength and flexibility. Biocompatible with effective osseointegration.
Disadvantages: Dark gray color can show through the gums, causing aesthetic concerns, Narrow-diameter implants may face mechanical issues in high-stress areas (e.g., molars).
|
Cobalt-Chromium-Molybdenum (Co-Cr-Mo) Alloys
| Description: Contains 63% cobalt, 30% chromium, and 5% molybdenum. Commonly used for custom implants like subperiosteal frames. Suitable for custom- designed implants.
Benefits: Strong, durable, and corrosion-resistant due to chromium content.
Disadvantages: Less corrosion-resistant compared to titanium.
|
Iron-Chromium-Nickel (Surgical Steel) Alloys
| Description: Known as surgical steel or austenitic steel. Contains iron, 18% chromium, and 8% nickel. Often used for stabilizer pins and frames.
Benefits: High strength, flexibility, and affordability.
Disadvantages: Lower corrosion resistance compared to titanium. Nickel may cause allergic reactions in some patients.
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Precious Metals (Gold, Platinum, Tantalum, Palladium)
| Description: Metals historically used for implants due to excellent corrosion resistance and biocompatibility. Gold was historically used but is now less common due to cost.
Benefits: Great corrosion resistance and biocompatibility.
Disadvantages: High cost and lower mechanical strength.
|
Ceramics in Dental Implants
Ceramics have been used in dental implants to help improve the bonding between the implant and bone, a process called osseointegration. For the past 15 years, various types of ceramic coatings have been applied to metal implants to enhance their performance.
Advances in material science and technology have renewed interest in ceramics for dental implants. Ceramics used in making imlants include aluminum oxide, zirconia, hydroxyapatite, calcium phosphate, and bioglass. Each of these materials has unique properties that influence their use in dentistry.
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Zirconia: A Leading Material for Ceramic Dental Implants
The name zirconium comes from the Arabic word “zargon,” which means “golden in color.” Zirconia first appeared in dentistry during the early 1990s, where it was used for clinical applications like frameworks for all-ceramic crowns, fixed partial dentures, and abutments.
Ceramic Implants (Zirconia and Variants) Failure Conditions
- Mechanical Failures:
- Brittleness: Prone to cracking due to bending forces or manufacturing imperfections (pores, microcracks).
- Surface Defects: Sharp angles or deep threads create stress points, leading to fractures.
- Small Diameter Implants: More susceptible to breakage under chewing stress.
- Chemical Failures:
- Low-Temperature Degradation (LTD): Exposure to moisture over time weakens the implant’s structure.
- Slow-Crack Growth (SCG): Cracks propagate slowly under constant stress, eventually causing failure.
- Surgical Factors:
- Excessive Torque During Placement: Applying too much twisting force can cause bending and fractures.
- Bone Density: Inserting implants into dense bone without proper preparation can lead to cracks.
Overview of the Different Types of Ceramic Implants
Type of Ceramic Implant Material | |
Y-TZP (Yttrium-Stabilized Tetragonal Polycrystalline Zirconia)
| Description: A type of zirconia stabilized with yttrium, maintaining the tetragonal phase at room temperature. Standard material for dental applications; reliable for implants.
Benefits: High strength, durability, low porosity, and high density.
Disadvantages: Reduced translucency when combined with alumina; brittle under high stress.
|
Aluminum Oxide (Al₂O₃)
| Description: A bioinert ceramic with excellent corrosion resistance, high strength, and wear resistance. Historically used but discontinued due to low survival rates.
Benefits: Corrosion-resistant, strong, and biocompatible.
Disadvantages: Poor long-term survival rate; withdrawn from the market.
|
Calcium Phosphate Ceramics
| Description: Includes hydroxyapatite and tricalcium phosphate; biocompatible and non-immunogenic. Used as coatings for implants or bone graft materials.
Benefits: Promotes bone growth and bonding with bone.
Disadvantages: Limited difference between coated and uncoated implants after long-term use.
|
Bioglass (SiO₂-CaO-Na₂O-P₂O₅-MgO)
| Description: A bioactive ceramic that accelerates bone formation. Commonly used for bone grafts and ridge repairs.
Benefits: Promotes bone growth (osteoinductive).
Disadvantages: Very brittle, limiting use in load-bearing areas.
|
Zirconia (ZrO₂)
| Description: A tooth-colored ceramic used for crowns, dentures, and implants. Comes in monoclinic, tetragonal, and cubic forms based on temperature.
Benefits: Excellent aesthetics, biocompatibility, and corrosion resistance.
Disadvantages: Brittle nature limits use in high-stress areas; requires careful handling.
|
TZP-A (Alumina-Added 3Y-TZP)
| Description: 3Y-TZP enhanced by adding alumina to improve durability and stability in high temperatures and humid conditions. Suitable for applications requiring strength in challenging environments.
Benefits: Increased durability and stability.
Disadvantages: Reduced translucency due to the alumina addition.
|
3Y-TZP (Yttrium-Stabilized Zirconia)
| Description: Contains only the tetragonal phase and uses yttrium to stabilize it at room temperature. The most commonly used zirconia in biomedical applications.
Benefits: Low porosity, high density, strong compression, and bending strength.
Disadvantages: Brittle and less translucent when combined with alumina.
|
Mg-PSZ (Magnesium-Partially Stabilized Zirconia)
| Description: Stabilized with magnesium to enhance strength and durability. Suitable for specific dental applications requiring durability.
Benefits: Greater toughness and stability compared to pure zirconia.
Disadvantages: Still prone to brittleness under extreme conditions.
|
ZTA (Zirconia-Toughened Alumina)
| Description: Combines zirconia and alumina to improve strength and fracture resistance. Ideal for applications needing extra toughness.
Benefits: Enhanced strength, durability, and wear resistance.
Disadvantages: Brittle nature limits flexibility and requires careful handling.
|
Polymer-Based Biomaterials for Dental Implants
In the early days of dental implant research, most experiments with MMA resin implants did not succeed. However, in 1969, M. Hodosh and colleagues introduced polymethacrylate tooth-replica implants. These implants were biologically compatible and marked the beginning of further developments in polymer-based dental implants. These tooth-replica implants successfully replaced natural teeth, helping restore both function and appearance.
Polymers offer several advantages. By changing their composition, researchers can adjust their physical properties, making them softer or more porous. They are also easy to handle, allow for better reproducibility, and improve the attachment of connective tissues. Compared to metals, polymers are easier to evaluate under a microscope and provide better aesthetic results.
Within dentistry, some of the most used PMs include polyethylene, polymethyl methacrylate, polycarbonate, polyethylene glycol, polyurethane and hexamethyldisilazane, to name a few.
Polymer-Based Implant Materials
Type of Polymer Material | |
Polymethyl Methacrylate (PMMA) | Description: |
Polyethylene (PE) | Description: |
Polypropylene (PP) | Description: |
Polyether Ether Ketone (PEEK) | Description: |
Biodegradable Polymers | Description: |
Current and Future Trends
Nanotechnology has brought exciting new possibilities to dental implants. With the help of nanotechnology, scientists can now create nanostructured materials like polymer nanocomposites. These materials allow dentists to design implants on computers with very precise shapes and tiny holes (porosity) that help the implant work better. Researchers are still studying whether these nano-sized patterns are better than traditional micro-sized patterns. However, the new nanocoatings have already improved the performance of dental implants. Thanks to these advancements, dentists can successfully use implants even in challenging situations, making treatments more effective and improving patient results.
Another promising advancement is rapid prototyping technology, a new manufacturing method where custom-made 3D implants are created using computer-controlled extrusion of materials. Rapid prototyping is cost-effective, reduces material waste, and allows for the reuse of unused materials. It also avoids milling issues, which can lead to tool wear, chipping, and reduced quality in zirconia implants. By enabling the production of detailed, high-quality designs, rapid prototyping technology allows for implants that perfectly fit each patient’s anatomy. This innovation holds great potential for improving both titanium and zirconia implants, offering more efficient and customized dental treatments in the future.
Conclusion
As dental implants become more popular, ongoing improvements in implant materials and designs continue to play a crucial role. The success of a dental implant largely depends on the materials used, the design, and the surface characteristics. Enhancing these factors helps achieve long-term stability and successful treatment outcomes.
For many years, titanium and titanium alloys have been the most commonly used materials for implants due to their excellent biocompatibility and mechanical strength. Zirconia-based ceramics offer even higher biocompatibility and better aesthetics compared to titanium, making them an attractive option. However, titanium implants still have superior mechanical properties and a long track record of reliable use.
In conclusion, titanium remains the top choice for most dental implants. However, Zirconia shows great promise for the future, but further research is essential to improve implant biomaterials and explore alternatives to titanium and zirconia. These ongoing efforts will help provide patients with better, more effective dental implant treatments.
Please, also check our blog about most famous dental implant brands.
References
- Osman, R., & Swain, M. (2015). A Critical Review of Dental Implant Materials with an Emphasis on Titanium versus Zirconia. Materials, 8(3), 932–958. doi:10.3390/ma8030932
- Oza, U., Parikh, H., Duseja, S., & Agrawal, C. (2020). Dental implant biomaterials: A comprehensive review. International Journal of Dentistry Research, 5(2), 87–92.
- Shekhawat, D., Singh, A., Bhardwaj, A., & Patnaik, A. (2021). A Short Review on Polymer, Metal and Ceramic Based Implant Materials. IOP Conference Series: Materials Science and Engineering, 1017(1), 012038. doi:10.1088/1757-899x/1017/1/012038