Properties of zirconia

It has the highest toughness and strength out of all advanced ceramic materials. Elastic modulus is a measure of stiffness of a material. Zirconia we mill at RR dental labs has an elastic modulus of 100 – 250 GPa at 20ºC, which is very high which makes it highly resistant to wear and tear. Zirconia is non-cytotoxic and is a bio-inert material which is potentially insoluble in water and is an excellent material of choice for all dental restorations. Single crystal fibres of yttria stabilized cubic zirconia is used in dentistry. At high temperatures, zirconia undergoes volumetric changes hence it is partially stabilized by adding yttrium, calcia and magnesia. Of the all-ceramic prosthetic materials, zirconium oxide (ZrO2 – zirconia) as a base material has shown great promise.

History

In the 18th century a scientist named Martin Heinrich Klaproth extracted zirconium and it stood out from all metals because of its excellent mechanical properties and biocompatibility. Zirconia was introduced in dentistry in the early 2000s, before that porcelain fused to metal (pfm) was the material of choice for a dental crown. Despite of the superior aesthetics of porcelain in PFM, the metal substructure affected the appearance of the crown. Due to these drawbacks, in the early 2000s zirconia was used in dentistry. It had the strength of a metal and looks of a ceramic, hence the name ceramic steel.

Biocompatibility of zirconia

Biocompatibility is the ability of a material to perform its function without causing any harmful effects to the body. At RR dental labs we mill zirconia for a variety of functions such as crowns and bridges, implant customized abutments, veneers, inlays & onlays. Oral environment being moist and maintaining a temperature of 36.68 degrees Celsius makes it the most suitable place for bacteria to grow. Traditional restorative materials had a high bacterial adhesion which caused failure of prosthesis due to gum infections and caries. Studies have shown that the adhesion of zirconia to bacterial biofilms is one of the least. Zirconia in relation to hard tissue(implant) showed superior properties than titanium. They showed greater bone to implant contact than titanium within 28 days of implant placement.

Zirconia in Dentistry

With the increase in awareness of oral health zirconia made its way into dentistry and stood out from the traditional porcelain fused to metal due to its superior strength and aesthetics. Zirconia for dental purposes are manufactured using CAD/CAM (computer aided Design and computer aided manufacturing) in three steps-

• 1. Retrieving of the digital data and physical impressions,

• 2. Designing in the computer (CAD)

• 3. Fabrication of zirconia structure (CAM).

We at RR dental labs, mill zirconia for a variety of functions such as crowns and bridges, implant screw retained prosthesis, individual crowns on Paulo-Malo frameworks, implant customized abutments, veneers, inlays & onlays.

CROWNS & BRIDGES

Modern dentistry is all about preservation of tooth as much as possible. Zirconia needs very less tooth preparation and should be the material of choice for all dental restorations. Traditional porcelain fused to metal would also stain the gingiva due to interaction of metal with the chromogenic bacteria which does not occur in zirconia. It also has superior aesthetics due to better light reflection properties which resembles that of a natural tooth. At RR dental labs our Zirconia monolithic classic are full contoured zirconia i.e the crown is fabricated from a single block of zirconia. The high strength and highly polished surface of zirconia monolithic classic makes it highly resistant to fracture and adhesion of plaque making it an ideal choice of restoration in the posterior region which is subjected to heavy occlusal loads. At RR dental labs we have the most advanced machinery to mill our zirconia restorations making it one of the most advanced labs in the world. With our machinery we have different classes of zirconia i.e i-dent zirconia Classic, i-Dent monolithic classic, i-dent premium, i-dent monolithic premium, i-dent zirconia platinum and i-dent Hollywood smile.

ABUTMENTS

Studies have shown that the inflammatory infiltrate in peri-implant soft tissue around the zirconia healing abutment was lesser than the traditional healing caps made of titanium. Zirconia abutments are generally used in patients with a thin gingival biotype as traditional metal abutments would leave a metallic hue which would be visible in aesthetic regions. The gingival attachment to a natural tooth or an implant is brought about by junctional epithelium. Zirconium nitride coating has shown better attachment with the junctional epithelium which provides a barrier between the implant and the oral environment, increasing the longevity of the prosthesis. Studies have also shown that the peri-implant soft tissue around a zirconia abutment showed better healing compared to that of traditional titanium or other alloys.

IMPLANTS

0.6% of the population are allergic to titanium which was the material of choice for dental implants. With its high flexural strength low modulus of elasticity, low thermal conductivity, and bio-inert properties zirconia implant came into existence. In the year 1988 Zirconia implants were first used for total hip replacement surgeries. In 2005 the first zirconia dental implant was introduced. Initially it was launched in the market as a single piece implant. Now it is available in two pieces making it convenient for the operator to customize the abutment as per their requirements. Studies have shown that the zirconia implants have a better Osseo-integration than that of titanium. Peri-implantitis which is a major complication of cement retained prosthesis over a titanium implant has not been reported in zirconia implants yet.

Implant Prosthesis

RR dental labs has pioneered in implant dental prosthesis making it the only lab using only digital outflow for fabrication of all prosthesis. At RR dental labs we fabricate screw retained prosthesis which should be used in places with lesser inter arch distance, cement retained prosthesis which is an excellent choice for restoration of an implant in the aesthetic region. We also mill Paulo-Malo framework which becomes an excellent choice to place zirconia individual crowns on all on 4 prosthesis making zirconia a viable option for full mouth rehabilitation patients.

Conclusion

With the help of advanced technology and most advanced machinery we at RR dental labs have been a pioneer in fabricating zirconia crown and bridges, veneers, implant customized abutment and zirconia crown on Paulo-Malo framework. We believe in making lives better by making their smiles better.