subject: Dental Implants Why They Work [print this page] Dental implants have skyrocketed in popularity recently because of dramatic improvements in success rates and the level of restorative tooth function they can provide. Like most revolutionizing medical and dental advances, dental implants have a long history over which time their viability has continued to increase. Only in the last couple of decades has their reliability really skyrocketed as demonstrated in clinical studies. This article outlines why todays implants are so much more successful and what factors contribute to the success. See how dental implants are placed for an overview of the process and illustrative images of implant components.
Early Evidence of Dental Implants Low Success
In the 1930s, an excavation of the remains of a young Mayan woman, believed to date back to about 600 AD, revealed some of the first-known evidence of dental implants. Actually, these implants were initially believed to have been placed for adornment after the young womans death a practice that was quite common in ancient Egypt. It was 1970 before a Brazilian professor used radiography to provide evidence that the Mayan womans dental implants (made of seashells) were placed before her death. The x-rays showed that bone had regenerated around two of the three implants. The scarcity of similar artifacts suggest a very low success rate at that time, although the Mayan culture was certainly noted for its advances and achievements. Little was likely known about why those dental implants worked (and why most others did not).
Experimentation Continued Successes Not Well Understood
Heavy experimentation in dental implants occurred in the 19th century. Gold and platinum were the materials typically used, and implants were frequently placed immediately after an extraction. By that time, the 18th century attempts to implant human teeth had already provided evidence that the human body would reject someone elses teeth. Even the 19th century implants that were initially successful didnt seem to last.
An Accidental 20th Century Breakthrough Provides Important Clues
The revolutionary advances in dental implants began in the 1950s when Swedish orthopedic surgeon Dr. P.I. Brnemark was performing research on bone regeneration and healing. He was studying the process by using optical chambers made of titanium that were screwed into bone. After making observations for a few months, he discovered that the (costly) optical chambers could not readily be removed for reuse because bone had formed and hardened around the titanium screws. Brnemark branched out of his standard field to study the exciting implications for implant dentistry, especially since the results (in the mouth) were more readily suited for clinical observation. (Today, of course, titanium implants are also very important in successful joint replacements and prosthetics.)
Brnemark and his team coined the term osseointegration to describe the successful structural and functional connection between living bone tissue and an artificial load-bearing implant. While his first titanium dental implants were successfully placed into a human volunteer in 1965, many years of intense research followed. It was not until 1982, when Brnemark presented his scientific data to the Toronto Conference on Osseointegration in Clinical Dentistry, that a significant turning point occurred in the acceptance and understanding of successes with titanium dental implants.
What Have We Learned Now About Success?
Today we know that there are many different factors involved in the success of dental implants and osseointegration, in general. Some of the most important factors are:
The biocompatibility of the implant material Titanium is a good material not so much because the body likes it, but because the body does not reject it. It does not tend to corrode like stainless steel. Biocompatibility is both a short-term and long-term consideration. Research on other biocompatible materials continues.
The design or shape of the implant Dr. Alvin Strock in 1937, working in a Harvard University lab, came up with the idea of using a screw-shaped implant, which is one of the most successful design shapes and most commonly used today. Additional design research continues.
The surface of the implant This continues to be one of the most highly-researched areas to determine what coatings should be used as well as how porous they should be to result in the best osseointegration and long-term result.
The condition of the receiving bone tissue Good bone health and good oral health in general have long been recognized as crucial factors for successful dental implants. For this reason, bone grafts and restorations often precede the implant process when the host tissue is not in good condition.
The implant surgical method How and when the bone and surrounding tissue is surgically prepared to receive the implant is very important. Excessive damage and disturbance of the bone tissue can diminish success rates. The topic of how many stages of preparation are required in order to achieve the greatest success is also the subject of recent research, concurrent with the emergence of one-step implant products/processes.
The load on the implant Research also continues on the influence of load (force) on the implant. The direction of the load is important, and will vary according to the position in the mouth. Detrimental load usually results in bone loss and eventual loss of stability of the dental implant. All aspects of load - including whether it can/should be immediate, intermediate, or delayed for certain conditions are still being explored in greater detail for their influence on successful outcomes.
While the success rate of dental implants is high (about 95% according to American Association of Oral and Maxillofacial Surgeons), the success rate varies according to the tooth position where the implant is being placed. The success factors identified above do not include other aspects of the patients general health that can affect outcomes. For example, those who have uncontrolled diabetes and those who smoke have significantly lower success rates. Your provider of dental implants will help you understand the success factors for your specific situation, including the importance of good oral hygiene before, during and after the implant process.
