How to: Complete a lower denture case

The original long-term studies on dental implants focused on solving issues associated with unsuccessful lower denture usage. It’s estimated that lower dentures have a less than 60% success rate. Patients who are unsuccessful in wearing and using their lower dentures fit the definition of a “dental cripple.” The issue is how to offer a reasonably priced solution to the dental profession with minimal surgical trauma. American Dental Implant’s Skinny 2.4 hybrid small diameter implant is a viable option.

About the implant

The Skinny 2.4 is a hybrid small diameter implant that offers full prosthetic versatility. The design of the small diameter threaded portion lends itself to flapless implant placement in ridges of adequate dimension. The design of the neck has the identical strength, prosthetic techniques and components of the standard internal hex, with no compromise in outcome.

The general advancement of flapless implant placement is well-documented. This greatly minimizes chair time, post procedural discomfort and surgical complications.

Case presentation

The patient is a 63-year-old female with a 20-plus-year history of unsuccessful lower denture use (Fig. 1). As with most candidates for implant therapy, cost and time away from work and family are significant concerns. A panoramic radiograph was taken confirming ridge was adequate for implant placement.

This procedure was accomplished with local infiltration only. No blocks were given. At one point during the osteotomy preparation, regional analgesia had to be supplemented.

Multiple infiltrations provide the implant surgeon with an understanding of the underlying bony anatomy. The infiltrations are approximate to the surgical site, so the injections can identify any hidden defects (Fig. 2).

After the infiltration, the area is swabbed with an antiseptic solution. The Locator Drill is then employed. The location must be in a safe area, anterior to the mental foramen and in the most desirable bulk of bone, but also as distal as permits a comfort level (Fig. 3). For this type of case, the length of the implant should not encroach on the inferior border. Pushing the length of the implant to maximize the depth of  available bone is counterproductive.

After the Locator Drill has initiated the osteotomy for both sites, establishing placement and trajectory, the Final Sizing Drill of the length of implant chosen is used (Fig. 4). Both osteotomies are accomplished sequentially, with no interruption in motion. The Final Sizing Drill has a countersink, providing a clear illustration of the ultimate depth of the implant’s coronal aspect (Fig. 5).

The implant is partially  threaded into the osteotomy using the finger driver from the delivery system digitally (Fig. 6). A ratchet wrench or any 4 mm square drive system is used to thread the implant to full depth (Fig. 7). For this case, all the procedures were accomplished bilaterally. If the bone is dense and the implant requires torque exceeding 50 newton centimeters, unthread the implant, and re-size the osteotomy with a 2.8 mm diameter internally irrigated drill. If the bone is soft and at least 25 newton centimeters of torque isn’t achieved, or if during the threading the implant strips the threads created in the bone, immediately unthread the implant and replace with a 3.7 mm tapered implant of the same length. It’s desirable to achieve 30 newton centimeters of torque during threading .

The O-Ring system is employed for this case because of its ease of use and cost containment. The green drivers are removed (Fig. 8). Before the abutments are threaded into the implants, red rope wax is placed in the denture (Fig. 9).

The denture is then seated providing a transfer of the exact location of the implants relative to the denture. The area is relieved to permit ample room for the brass keeper in the denture.

The O-Ring abutments are threaded into the implants, being cognizant of the two different tissue heights (Fig. 10).

Red rope wax is placed sparingly around the base of the abutment, as a block out and to stabilize the brass keeper (Fig. 11). Brass keepers are then snapped onto the O-Ring abutments with the wide flange toward the denture.

The final surgical radiograph is taken. While the radiograph is developing, the acrylic of the denture is removed in the area of the implants to create a chamber for the brass keepers (Fig. 12).

The denture is finished and seated (Fig. 13). It’s important that no interferences exist between the implant assembly and the proper bite and seating of the denture. Apply cold cure denture reline material to the holes in the denture to pick up the brass keepers.

Clean up the flash and dismiss the patient. Total chair time was 53 minutes. This procedure is a beneficial, cost-contained dental implant therapy. Also, because the Skinny 2.4 has a conventional restorative chamber, the patient at any time in the future can add more implants and enhance the restoration.