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Immediate Function with Dental Implants

Computer-Guided Dental Implant Surgery

Tilted Dental Implants for Better Support of the Replacement Teeth

Immediate Function with Dental Implants

In years past, when a dental implant was placed in the jaw, there was a waiting period of three to six months before a tooth could be attached.  During this time, a patient would either go without a tooth, or have a removable replacement.  Now, all this has changed.

With regard to dental implants, the term "Immediate function" means that temporary artificial teeth are attached to dental implants within 48 hours of implant surgery.  You may have heard about immediate function under some of the trade names like "teeth in a day," or "teeth in an hour." 

With immediate function, just after implant surgery, patients are cautioned about what and how they eat.  However, they are able to use their new teeth right away, and can also enjoy improved appearance. 

The three to six-month waiting time described above is necessary for the body to grow new bone directly against the surface of the dental implant, a process called "osseointegration."  Osseointegration is still critical to the success of a dental implant, since it enables the implant to withstand the forces of chewing.  However, we now understand that, as long as an implant can be kept from moving, it may be put into function before osseointegration is complete.  For an immobile implant, healing continues undisturbed.  

Two factors that help keep an individual implant and attached artificial tooth from moving during function are (1) placing the implant very tightly into the bone, and (2) keeping the artificial tooth slightly out of contact with the opposite teeth.     

When many teeth are missing, and therefore multiple implants are placed, the implants must have a known level of tightness in the bone, and must be joined together around the dental arch by a rigid, temporary tooth replacement.   When multiple implants are present, it is often permissable, and indeed necessary, for the artificial teeth attached to them to be in contact with the opposite teeth.

The dental surgeon placing the implant can measure the tightness, or "insertion torque," of an implant newly-placed in the jaw.  Based on this information, the surgeon determines whether immediate function is appropriate.  Patients and dentists must keep in mind that the requirements for immediate function are not always met.  Therefore, this approach should not be used in all situations.

Computer-Guided Dental Implant Surgery

Computer-guided dental implant surgery  begins with the construction by the prosthodontist of a radiographic imaging guide (RIG).  A RIG is comprised of replicas of the specific teeth that are missing, mounted on a plate that clips into the mouth.  The replicas of the specific missing teeth are made from an acrylic resin containing barium sulfate, a chemical that shows up on x-rays.  The RIG is positioned in the mouth when a CT (computed tomography) scan is made.

A CT scan is a three-dimensional picture of the anatomy of the upper or lower jaw.   The usual dental  x-ray is a two-dimensional image. Conventional x-rays are fine for routine dentistry.  In fact, three-dimensional x-rays expose the patient to more radiation, and should not be used for routine screening purposes.  Nevertheless, CT scans are important for the evaluation of special problems, and particularly for planning dental implants.  In the past few years, a new type of CT scanner, called a "cone beam (CBCT)," has been introduced.  A cone beam scanner produces images of a quality sufficient for dental implant planning and surgery, and exposes the patient to significantly less radiation.  

In computer-guided implant surgery, a CT scan made with a RIG in place results in a three dimensional x-ray containing silhouettes of the future replacement teeth.  By studying this scan, the surgeon and prosthodontist can see the distance of the bone from the future tooth positions.

By means of interactive software, the surgeon and prosthodontist can place implant icons directly on the CT scan at locations close to the future tooth positions, at sites where the bone profile is the most favorable.  This is called "virtual surgery." The implant icons are carefully placed in locations that avoid sensitive anatomic structures like sinuses and nerves.

 After the most favorable implant positions have been determined, the goal is then to reproduce this virtual surgical plan during actual implant installation.

The device which makes this possible is a  "surgical guide," pictured above.  This device is actually manufactured by the software. The holes with metal sleeves guide the surgeon in placing implants in the precise positions determined during the virtual surgery.

 In summary, computer-guided surgery  involves (1) creation of a radiographic imaging guide, (2) a CT scan with this guide positioned in the mouth, and (3) manufacture of a surgical guide based upon the planned positions of the implants, and (4) actual surgical placement of the dental implants

By means of these steps, dental implants are placed safely and accurately according to a pre-determined plan. 

Tilted Dental Implants for Better Support of the Replacement Teeth

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