The success of newer implant systems is presently revolutionizing dentistry. Although some dentists have not participated in this revolution yet, it will occur and dentistry will never be the same.
Compared to other dental innovations, implantology has enjoyed a rapid and progressive development. The quantum leap made in implant dentistry has been the result of tireless work by contemporary dentists who have pioneered the surgical and prosthetic procedures to which all of us today owe a debt of gratitude. Preceding this clinical advance is a solid foundation of research that definitively supports dental implantology as a viable alternative to conventional dentistry. Included in this framework of bio-science are a myriad of advances in new implant systems, implant bio-materials and new, improved diagnostic procedures to guide our surgical techniques. Added to this are advances in manufacturing of precision fit components which allow accurate dental restoration in concert with state of the art manufactured dental implants.
Today over 200 different dental implant systems are on the global market. Fifty different systems with FDA approval are available in the United States. Some of the newer systems incorporate technological advances which continue to improve the long term survivability of dental implants and the restorative dental appliances placed upon them.
The first attempts by man to replace lost teeth with implants dates to the 18th century when it was common practice to replace lost teeth with the teeth of other individuals. These individuals were usually young boys or girls who were paid for their donation. The implantation of other individuals teeth met with resounding failure as the body's immune system quickly attacked the foreign tissue leading to infection and rejection of the tooth.
Early pioneers in implantology quickly realized that other inert material such as ivory or gold were not rejected as quickly. Even though these materials were an abhorrent failure as well, it took longer for the body to reject them. Implantologists went back to work experimenting with different metals. In 1891 a physician named Hartman proposed that dentures be fixed to the jaws using metal screws. Although a great number of failures quickly led to the demise of this procedure as well, the foundation was laid for the first crude, potentially successful dental implant system. In 1939 a dental clinician by the name of Stock attempted to alter the shape of the dental implant to resemble a wood screw. This ushered in a new era of dental implantology with multiple variations of Stock's initial work.
In spite of new materials and shapes, implant success was fleeting. Although the implant site healed, loading of the dental implant with a crown or bridge quickly led to loosening of the fixture, with infection and failure.
It was during the early 1950's and 1960's that Per Ingvar' Branemark, beginning at the University of Lund and continuing at the University of Gottenburg in Sweden began researching the healing capabilities of the human body. One of his experiments involved the incorporation of two different types of metal cylinders into the jaw bone of rabbits. These metal cylinders were implanted in the bones of the rabbits to determine how the body healed after injury. Dr. Branemark theorized that the only way to observe the healing process was to place small optical chambers inside the metal cylinders directly in the bone. He observed that, at the end of the experiment, the optical chambers housed in titanium metal would not come out. They had "fused to the bone". He coined the term for this fusion "osseointegration". He used this term to describe the reaction of the titanium to the bone. This term is still used today and describes the successful placement of the dental implant into the jaw.
On the basis of these experiments other trials followed. This culminated with the development of an implant system that could be surgically placed in the jaws, allowed to osseointegrate and then be restored with metal connectors to artificial teeth and modified dentures.
Branemark implant system
With a few modifications, Branemark's system of dental implants has evolved into the most successful implant system in use today. New sizes and better and more user friendly components for the attachment teeth have been forthcoming.
Screw Implants (Left to Right: TPS screw, Ledermann screw, Branemark
screw, ITI Bonefit screw)
Cylinder Implants (Left to Right: IMZ, Integral, Frialit-1
step-cylinder, Frialit-2 step-cylinder)
Blade Implants (Left: Single-post Biolox implant, Right:
Single-post, two-stage titanium blade implant)
A great deal of information must be assimilated by the general dentist and oral surgeon to determine if you are a candidate for dental implants. Not all patients are candidates. In some cases more traditional, less expensive dental restorations will suffice to return the patient to good chewing function. Function is the key word. What is good chewing function for one patient may be inadequate function for another. Therefore, who is and who is not a candidate for dental implants requires a lengthy work-up to include x-rays, plaster molds of the occlusion and a detailed analysis of the patient's functional needs.
Just as important as the physical findings are the psychological needs of the patient. Losing ones teeth and replacing them with false teeth is not easily accepted by many patients. Those who find it emotionally traumatic are most appreciative of the dentist's ability to replace natural teeth with appliances that are firmly anchored to the jaws. Some of the questions that must be answered by the initial work-up are:
In addition to these questions which must be answered, there are many medical conditions which contraindicate implant placement:
Dental implantology demands that the oral surgeon and restorative dentist have a profound grasp of the biological, physical and engineering principals which govern the placement of implants. In addition, the specialist's office must be structured and organized to stress the art of implantology. What is needed?
DIAGNOSIS AND TREATMENT PLANNING
The first step in successful implant reconstruction is the hardest; diagnosis and treatment planning. Before attempting any implants several steps must be completed.
ANALYSIS OF X-RAYS AND MOUNTED PLASTER CASTS
Periapical Radiograph with Gridwork
x-ray showing entire jaw
Implant template overlying lower jawbone
Lateral cephalometric radiograph
demonstrating height of lower jaw
Occlusal radiograph of the front of the lower jaw
X-rays of the jaws help to quantify and qualify the amount of bone available to support the dental implants. Implants come in various diameters and lengths. With few exceptions, the longest and widest diameter implant that is possible to place in the jaw is the size favored. Many physical variables must be taken into consideration when determining the best size and shape of the implant, i.e.:
Mounted plaster casts are important diagnostic tools because they allow the oral surgeon to accurately plan the placement of the implants. They also allow the dentist to prepare a WAX MODEL of the anticipated final restoration before the implants have been placed in the bone. Any changes in the position of the implants to achieve the most stable restoration can be made in the plaster and wax model first.
Successful implants require good bone and plenty of it. Determining the amount of bone available and its quality is part science and part radiographic interpretation. The thickness of bone and the height of bone available is easily measured on CT DentaScans. The quality of bone, however, is harder to determine. The success of the implant is partly determined by how much surface area of the implant is embedded in and in intimate contact with the patient's bone. Denser bone, more calcified bone, provides a better interface for implant stabilization. Several classifications systems attempt to rate bone quality. These are beyond the scope of this Website. Suffice it to say that quality is as important as quantity. This becomes very apparent when one compares the success rate of upper jaw implants to lower jaw implants. The upper jaw is less dense. How long the implants will last is affected by this fact and is reflected in the increased success rate seen in lower jaw implants. Quality of the bone is one of the variables that, unfortunately, cannot be accurately determined prior to the placement of the implant.
DETERMINING THE EXACT LOCATION FOR THE IMPLANT
Successful reconstruction with dental implants requires accurate placement into good quality bone. The placement of the implant at the exact angle and position is paramount to success. As little as a few degrees error in placement or a few millimeters of error in position can limit success. Just like the foundation of a building or a bridge across a river, placement of the foundation is necessary for stability.
POOR ANGULAR POSITION
CANTILEVER (avoid excessive
angulation)
Left: Proper orientation
Middle: Unnecessary forward flare
Right: Angulation too far toward the palatal causing cantilever forces
Left: Ideal implant is placed vertically
Right: Implant placed at a poor angle
CANTILEVER and POOR ANGULAR POSITIONS are to be minimized at all costs. To accurately place the implant requires a dental work-up that includes x-rays, preparing a wax model and mounted plaster casts. From the casts, the dentist will fabricate a surgical template to guide the placement of the implants into the bone.
Diagnostic plastic lower denture
View of same plastic denture from above
Panoramic radiograph with measurement spheres embedded in plastic denture
to guide the placement of the implants
Long-term success of the dental implant requires a concerted effort on the part of the surgeon, the restoring dentist and the patient. Successful implant dentistry requires:
Proper placement , proper restoration and proper care ensures success. In spite of achieving these three requirements implants do not last forever. Success is measured in years of service. It is not measured by forever. All implants must be maintained and ultimately revised and replaced.
TO OBTAIN AND MAINTAIN A SUCCESSFUL IMPLANT THE ORAL SURGEON MUST:
To define success of implant systems the United States Department of Health and Human Services convened a conference on dental implants at Harvard University in 1980. At that conference success was defined as a 75%, five year survival rate of an implant. Today success rates surpass those defined by the 1980 Harvard conference. Today 90% 15 year success rates are commonplace for some implants.
A recent article in the International Journal of Oral and Maxillofacial Implants, entitled "Osseointegrated Implants for Single Tooth Replacement: A Five Year Multi-Center Study" sited a 96%, five year survival rate of single tooth implants placed in the upper jaw. Success rates were even better in the lower jaw. How long your implants will last is impossible to predict. However, many clinicians agree that dental implants can be one of the most successful dental procedures done today.
REPLACING MISSING TEETH WITH IMPLANTS
Click here to view our extensive
information on REPLACING MISSING TEETH WITH IMPLANTS (Warning: This page contains some
graphic images of surgery.) 
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Copyright © 1997 Michael B. Lee, D.D.S.
Last Updated on April 10, 2003
This site developed by SUPPORT CENTRAL and Dr. Michael B. Lee
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