A growing population of patients are missing some or all of their teeth. In the past, the only treatment option for patients whose dental health had deteriorated to this extreme was a partial or full denture.
Unfortunately, the replacement of natural teeth with dentures is commonly associated with some undesirable physical and emotional changes. Patients who had all of their teeth removed and replaced with an immediate denture frequently found the abrupt transition very difficult. As soon as the teeth are removed, the constant stimulation to the bone once provided by chewing no longer occurs, and the bone and tissue structures that once supported the teeth begin to resorb (figure 1).
Over time, changes in the mouth can cause dentures to fit poorly, creating uncomfortable pressure on gum tissues. Many denture wearers experience difficulty with maintaining a proper diet because eating is associated with denture pain or discomfort. Dentures can also interfere with speech and cause social embarrassment when they slip unexpectedly. In the long-term, most patients have found dentures to be a less than satisfactory solution.
EARLY IMPLANT METHODS
Dental implant technology has undergone significant evolution. In the early days, the dentist refracted the gum tissue to visualize the bony anatomy. This visual assessment and strategic implant placement was critical in order to avoid nerves and ensure proper position and function of the final replacement teeth. (Visual assessment yields less predictable results when there is extensive bone loss or when multiple implants are planned.)
The implants were then left undisturbed for six to nine months to allow the titanium implant posts to form a secure bond with the jawbone. During the six months or so while the titanium bonded to the bone, the patient either went without teeth or continued to wear the old dentures. In a second procedure, the implants were uncovered and the posts were attached. The teeth were then affixed to those posts.
With the development of dental implants, dentists are able to offer a superior alternative to the conventional partial or full denture. Additionally, new improved implant procedures have been developed and refined in response to the demand for greater accuracy and shortened treatment time. These new procedures enable the restoring dentist to place dental implants and attach replacement teeth in the same visit.
IMMEDIATE PROVISIONAL HYBRID
The treatment process begins with making a denture, of the same type that is typically created when teeth are extracted or existing dentures are replaced. This is converted into a temporary hybrid denture at the time of implant surgery. The surgeon then places dental implants and installs temporary abutments (Figure 2). The extraction site is sutured to close the gum tissue.
At this time, the restoring dentist modifies the new denture to fit over the temporary abutments (Figure 3a). Although there is a short learning curve associated with this step, it becomes very easy after completing a few cases.
This step can be completed ahead of time if the implants are placed with the NobelGuide procedure by Nobel Biocare. A presurgical working model is made using a surgical template and the holes are predrilled prior to the day of surgery (figure 3b, 3c).
After the denture is properly fitted over the temporary abutments (Figure 4) the denture can be processed in the mouth to the abutments.
The access holes are plugged with plastic Q-Tip rods to prevent acrylic from closing off the opening to the abutment screw.
The denture is now processed to the abutments using fast-set denture repair acrylic. This is achieved by placing the uncured acrylic in a plastic syringe and expressing it into the opening in the denture next to the abutments (Figure 5).
The denture is held firm until the acrylic cures completely. At this time, the Q-Tip plugs are removed and the denture in converted into an implant-supported hybrid denture. All excess acrylic and most of the denture flange is removed to make a high water type appliance.
After the appliance is adjusted, the underside is polished and glazed for a smooth finish that facilitates proper hygiene (Figure 6).
The hybrid is then attached back to the implants. The screws are torqued to 35 Newtons and the access holes covered with cotton and cavit.
The patient left the day of surgery with a fixed hybrid denture (Figure 7) that served him for three to four months while the implants completely integrated.
During this time, we addressed any issues of occlusion and function. The patient was restricted to only fork-mashed food for the first three months, after which he was able to resume eating normal food.
The final restorations were delivered in four months. The patient is extremely pleased with the final outcome (Figure 8).