Written by William Letcher, DMD Tuesday, 01 January 2008 00:00
The full lower denture is arguably the dental procedure with the most dissatisfaction for both the dentist and the patient. To be blunt, the full lower denture really doesn’t work. Believing that using multiple impression materials with proprietary trays and getting a perfect bite registration for a special occlusal scheme will produce a satisfactory result is just plain naïve. Root-form implants can greatly improve the success rate in restoring the lower arch with a fixed prosthesis, but there are many patients who have too little bone for these implants. Only a wealthy few can afford the time and money to have the necessary bone grafts for a fixed restoration on an atrophied mandible. As a result, there are many denture wearers who must suffer the pain and embarrassment of a full lower denture for life.
In the case presented in this article, a solution to the above dilemma is described. This particular solution is a procedure known as FixtTeeth (a trademarked term). It involves the use of small diameter implants supporting a full arch of hybrid resin teeth which is rigidly fixed in the patient’s mouth. The implants are immediately loaded and stabilized. Plus, the surgery and placement of the resin teeth are completed in one appointment.
Figure 1. Patient had recently received a new lower denture.
Figure 2. CT scan shows severe bone loss, and provides cross-sectional views at various points along the mandible.
Figure 3. 3D image shows the mental foramina to be on the superior surface of the bone.
Figure 4. There is a minimal amount of bleeding after implant placement.
Figure 5. Addition of pink resin to simulate gingiva.
Figure 6. Finished resin teeth articulated to the opposing denture.
Figure 7. Panoramic radiograph of the finished restoration.
Figure 8. Intraoral view of resin teeth approximately 10 days after surgery.
The patient was a 65-year-old white female who had worn full dentures for 4 decades. She had recently had a new lower denture made because of continued deterioration of her mandibular bone. She had been told that she didn’t have adequate bone for dental implants. The new denture is shown in Figure 1. A CT scan (Figure 2) showed not only the severe bone loss, but it provided cross-sectional views at various points along her mandible. The vertical bone height was less than 8 mm at its narrowest points just behind the mental foramena. The 3D image in Figure 3 shows the mental foramina to be on the superior surface of the bone. There also appears to be a bony ledge in the symphysis region, which could make implant placement challenging if done without the benefit of the 3D image.
Bilateral mandibular block anesthesia was administered after the patient was se-dated with 0.5 mg of triazolam 90 minutes earlier. Without laying a flap, a 1.2 mm twist drill was used to perforate the cortical plate, and ten 2.0 x 13 mm MDL mini-implants (Intra-Lock, distributed by Ultimatics) were inserted in the holes made by the twist drill. The sharp tips and crisp threads allowed for the self-tapping insertion of the implants with 30 to 45 Ncm of torque applied to every implant. The result can be seen in Figure 4, noting the minimal amount of bleeding.
At a previous appointment, records were taken to establish the vertical dimension, acquire a centric bite, and choose an appropriate shape of teeth. From this denture set-up, a plastic mold was made to form the teeth using approximately 20 gm of Cosmedent’s Renamel microhybrid composite resin.
Figure 5 shows the addition of pink resin to simulate gingiva. The finished resin teeth are shown articulated to the opposing denture in Figure 6. The resin teeth were then cured directly onto the implants in the mouth. Figure 7 is a panoramic x-ray of the finished restoration and Figure 8 is an intraoral view of the resin teeth approximately 10 days after the surgery.
With the FixtTeeth procedure as described above, at the initial patient visit a CT scan (i-Cat by Imaging Sciences) is made to view the density and shape of the mandible. At the same appointment, impressions are made of the upper and lower arches to establish the vertical dimension and the centric bite for a new lower denture. Denture teeth are set with a minimum of wax; no flanges. Then, a plastic mold is made of this denture set-up and surrounding soft tissues.
At the next appointment, which can be as soon as the next day, 8 or 10 mini-implants (2 to 2.5 mm diameter) can be placed in the mandible without incisions because of preopt 3D information from the i-Cat. An impression is made of the lower arch and poured in quick setting stone. The plastic mold of the denture set-up is filled with hybrid Renamel and fitted to the stone model. The resin is cured and removed from the stone model. Defining and polishing the resin teeth is finished before trying the teeth in the mouth and adjusting the occlusion. Finally, additional resin is placed on the intaglio surface of the teeth and inserted on the implants. Excess resin is removed and the teeth are cured to the implants. The lower border of the teeth is trimmed so as to keep the bucco-lingual dimension of contact between the resin and soft tissues to a minimum (less than 4 mm). This will allow cleansing with a toothbrush and a water-irrigating device. The patient is then seen 10 days later for a final polish and occlusal adjustment.
FixtTeeth is a unique and revolutionary technique to restore the edentulous arch with teeth that are rigidly fixed in place. It uses implants that are less than one sixth the cost of standard-sized implants, and lab costs are eliminated if the dentist makes the teeth. It takes about the same amount of time to make the resin teeth as it does to make a full arch of temporary crowns. The surgery and placement of the teeth takes one appointment. At this point in time, no patient has been denied FixtTeeth due to lack of bone; everyone has been treated without bone grafts. Each patient with a full lower denture has been given the guarantee that if for any reason they don’t feel that the FixtTeeth is worth the fee, I will remove the teeth and implants and refund 100% of their money. So far, no one has exercised this option. (Note: To observe this procedure, call (918) 743-4496 and ask about the details.)
FixtTeeth is a life-changing procedure. Some patients will be genuinely gratified with the results. Dentistry can now offer a service to patients with too little bone for standard sized implants.
Dr. Letcher graduated from St. Mark’s School of Texas in 1967, Washington University in St. Louis with a BA in Mathematics in 1971 and DMD in 1975. He is a Fellow of the Academy of General Dentistry, graduated from the L.D. Pankey Institute and the Misch Implant Institute. Professional memberships include: ADA, Oklahoma Dental Association, Tulsa County Dental Society, Academy of General Dentistry, American Academy of Cosmetic Dentistry, and American Academy of Implant Dentistry. He can be reached at (800) 742-4496, or visit LetcherDMD.com.
Disclosure: Dr. Letcher holds US patents in crown fabrication and is the inventor of FixtTeeth, the revolutionary process for people with missing teeth and complex dental problems.
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