A promising development is emerging in the area of dental implants. New materials—including zirconia and plastics—are being used in addition to time-tested titanium.
In the 1967 film classic The Graduate, there’s a famous scene at a party for the new graduate in which a family friend offers him some advice about the future. “I want to say one word to you. Just one word,” says the friend. A pause: “Plastics.”
That very word is expected to cause a buzz at the International Dental Show (IDS) in March 2017 in Cologne, Germany.
“Plastic implants are becoming interesting. For example, those made out of PEEK (polyether ether ketone) are suitable for the minimally invasive flapless method (insertion without mucoperiosteal flaps). In the future, related materials could also gain in significance, namely PEKK (polyether ketone ketone). In addition to the pure ceramics and pure plastics, hybrid materials that attempt to combine the best of both worlds are also exciting,” wrote IDS organizers in a press release.
Dr. James Rutkowski, a Pennsylvania dental implant specialist, is editor of the Journal of Oral Implantology published by the American Academy of Implant Dentistry. In his opinion, plastics offer some possibilities for dental implants, but are not yet ready for prime time. “PEEK shows some promise, but not a lot,” he told us. He believes it has demonstrated its benefits in orthopedic spinal fusion, “but currently does not withstand the environment of the oral cavity well.” Rutkowski added that PEKK is very new and may be useful in temporary restorations. “PEEK and PEKK need further development,” he said.
Zirconia Is Popular for Cosmetic Reasons
One alternative is zirconium dioxide, a white crystalline substance known as zirconia.
Rutkowski said zirconia, which is considered a ceramic and not a metal, is especially popular for cosmetic reasons. “The upside to zirconia implants is that there is no dark color. It is white or more tooth-colored as it emerges from the gum,” he said. “The aesthetics are better, so it’s better for the front of the mouth.”
Traditionally, zirconia implants come in one-piece models. “However, various two-piece alternatives should be available in time for IDS 2017—optionally with an adhesive bond or a screw connection,” noted the IDS announcement.
“[The new zirconia implants] are devised to enable a closed healing, which is as a rule not possible with one-piece implants. If it ‘only’ comes down to the aesthetics, a host of ready-made ceramic abutments for titanium implants are available as a further option. Alternatively, individual abutments can be made using the CAD/CAM technology.”
It All Started With Gold
Dental implantology has seen its materials evolve. “Since the beginning of mankind, humans have used dental implants in one form or another to replace missing teeth,” said Celeste Abraham, DDS, in The Open Dentistry Journal. Abraham is associate professor in the Department of Periodontics and Stomatology Center at Texas A&M University in Dallas.
It all started with gold in 2500 BCE in Egypt and moved through ivory and stone to bits of shell used by the Maya. There were even some dubious attempts to replace missing teeth involving grave robbers. The modern era for implants began in the 1930s. After noting that orthopedic surgeons used Vitallium (a chromium-cobalt alloy) in hip bones, researchers produced a Vitallium screw to anchor and support replacement teeth.
Refinements in design and materials continued. Cobalt and stainless steel implants were used, but there were problems. “The stainless steel corroded, and the chrome cobalt leaked some of its minerals,” Rutkowski said. “It is referred to as ‘stain-less,’ not stain impossible.”
The real breakthrough was implants made from titanium and titanium alloys.
Gabor Balogh, DDS, who practices in Vancouver, Canada, said, “Today’s modern day dental implants developed through an accidental discovery in medical research back in 1952. A Swedish doctor found that when titanium was placed into contact with bone and left undisturbed, the bone grew right against the surface, making the titanium objects un-removable without cutting out the bone around the titanium. This developed into today’s implants.”
When titanium was placed into contact with bone and left undisturbed, the bone grew right against the surface.
Still, researchers and manufacturers have continued to explore alternatives. Arun Garg, DMD, a former professor of surgery in the Division of Oral/Maxillofacial Surgery at the University of Miami now in private practice, said some patients resist the idea of putting metal in their mouths, fearing autoimmune diseases.
Garg stressed that there is no proof that titanium causes any health problems. “Since titanium dental implants have been in use, there has not been one report of an allergy or reaction to the metal itself. Nevertheless, there are some people who have either an allergy or sensitivity to other metals (e.g., prevalence of nickel allergy is about 5%) and/or simply have concerns about any metals within the body,” said Balogh.