Why ceramic implants are a good alternative
Today more than ever, ceramic implants are the talk of the town. Their main advantages are tissue compatibility and low plaque accumulation. One-piece ceramic implants have been established on the market in dentistry for some time now. In the past, two-piece solutions were considered too risky, but a lot has happened in this field.
Ceramic implants: How it all began
Dentists have been successfully using titanium for dental implants for years. The first clinical use of these products dates back more than five decades. At the same time, ceramic implants made of aluminum oxide were developed, which were later also used in clinical applications.
Titanium implants have since established themselves as the gold standard and are used to anchor removable and fixed dentures. With its low fracture toughness, however, aluminum oxide has not been able to establish itself as a material for implant manufacture.
Zirconium oxide - modern high-performance ceramic with many applications
Zirconium dioxide has become the material of choice for the manufacture of ceramic implants. This material belongs to the family of high-performance ceramics. This material has a particularly high fracture toughness. This is due to the polymorphism of the underlying lattice structure. Possible are
- monoclinic (room temperature up to 1'170 °C),
- tetragonal (1'170 to 2'370 °C) and
- cubic (2'370 °C up to the melting point) lattice structures.
Passing the respective temperature barriers causes a volume change in the microstructure. By adding special oxides, unwanted volume jumps during production can be avoided. They prevent a phase transition from tetragonal to monoclinic during cooling after the sintering process.
If a load-induced crack formation occurs, crystallites adjacent to the crack convert their lattice to the monoclinic modification. This causes the aforementioned increase in volume. This results in a compressive stress in the microstructure - the progression of the crack can be stopped in this way.
However, you must be aware that even with this high-strength ceramic there are limits and peculiarities. Despite optimal self-healing potential, failure can occur if manufacturing-related flaws turn out to be too large or a specific critical thickness of the transformed layer is reached for the respective workpiece.
Why are ceramic implants an optimal alternative?
As already mentioned, titanium is one of the proven materials for implant manufacturing. It is characterized by high stability, and most patients show good tolerance.
If there are metal allergies, intolerances or patients are concerned about metal exposure of the organism, an alternative to titanium is needed. To replace missing teeth, ceramic implants are an ideal option and the only alternative to titanium implants.
The properties of ceramic implants
Basically, the metal-free alternative is an ordinary implant screw. Only it is not made of titanium, but of the high-performance ceramic zirconium oxide.
This extremely stable and very fracture-resistant material is particularly suitable for medical and dental applications. Unlike titanium implants, however, they are preferably used in one piece. As a result, it is more difficult to apply the actual dental prosthesis.
Much has changed here: two-piece systems are now available. For a durable and optimal hold, the two elements are bonded together. However, not every tooth is suitable for the two-piece model. In this case, your dentist's office is the right contact. The highest priority should be a fixed denture.
Wide range of applications in dentistry
Metal-free implants offer a wide range of applications. It ranges from the replacement of single teeth to bridges and the stable anchoring of removable dentures.
Since it is less visible, the ceramic implant is preferably used in the area of the front teeth. However, there are also very good solutions on the market with two-piece ceramic implants, as the treatment is easier for the dentist to reach the back molars.
The advantages of ceramic implants
High biocompatibility
The material does not release any particles to the tissue. Even saliva cannot harm it; no substances are released as a result. Incompatibilities or allergies, which are common with metals, do not occur. Subliminal inflammation or toxic effects of the implant are excluded.
Optimum esthetics
The high-performance ceramic has a color that closely resembles real teeth. In contrast to dark titanium, this prevents gleaming through. If the gums recede, the implants remain much more inconspicuous.
The attachment of gums
The ultramodern material is not only well tolerated by the tissue. Gum tissue is also readily attached to the ceramic implant in question. According to studies, the tissue even grows better to the material than to the natural tooth. For example, if receding gums occur frequently with titanium implants, they can be prevented with a ceramic implant.
Bacteria-unfriendly environment
Bacteria do not like ceramics. This prevents peri-implantitis, i.e. inflammation around the implant. Unfortunately, the risk cannot be completely eliminated. Since only a few bacteria accumulate on the ceramic surface, the risk of inflammation is minimized.
Ceramic implants in the medical field
In medicine, the high-performance ceramic zirconia is often used as a starting material for the manufacture of hearing and finger endoprostheses. Hip joint replacement is another part of the wide range of applications.
As already mentioned, the high-tech material has also long been established and proven in dental medicine. Root pins, crowns and bridges are made from it, as are brackets for orthodontics. Surgery also benefits from its advantages. Here it can be used as a base material for implants and abutments.
Not all ceramics are the same
Depending on the intended use, it is possible to stabilize the cubic shape (cubic stabilized zirconia, CSZ). The concentration of the added oxide also allows a fundamental distinction to be made between
- fully stabilized zirconia (FSZ) and
- partially stabilized zirconia (PSZ).
When comparing fully stabilized and partially stabilized molds, a reduced amount of added oxide is noticeable in the PSZ ceramic. As a rule, an attempt is made to stabilize the cubic phase in PSZ ceramics. At the same time, the monoclinic and tetragonal phases are present in this material.
Ceramics consisting of 100% of the tetragonal phase of the ZrO2-Y2O3 system are called TPZ (tetragonal zirconia polycrystals) ceramics. In order to produce these ceramics, a high degree of chemical purity is required as a basic prerequisite for the starting materials. As a rule, ceramic implants consist of a Y-TZPA ceramic.
The proportion of aluminum oxide is 0.25% lower than in a Y-TZP ceramic. Manufacturing techniques allow optimization of the material properties. The aim is to obtain a material with a virtually 100% dense structure. For this purpose, the process known as HIP is used. This allows a uniformly fine grain size with a high degree of purity.
The HIP (hot isostatic postcompaction) process is performed downstream of sintering. Under high pressure, in a protective atmosphere (argon) and slightly below normal sintering temperatures, the defect and void content is reduced. At the same time, purity and density increase. This results in reduced fracture behavior (modulus of rupture, MOR).
High durability and a natural appearance
It is not only for dental implants that the material used must meet high requirements. The implants should remain in the body for a long time. Therefore, biocompatible materials with high strength and good compatibility are the focus of implantologists.
It is also important that the material grows firmly into the bone and surrounding tissue. The white color of the material also meets high aesthetic demands. BSQ TECH GmbH is an expert in technical ceramics and related products.
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