Dental Implant Hybrids for Maximum Esthetics
A next-generation option for implant-retained prostheses
Patients are generally aware of their dental problems when they present to their clinician's office. Part of the clinician's job is to keep up with the newest and best techniques and to educate patients about the benefits and risks of available procedures. Implant dentistry, which has become a routine and effective means for restoring edentulous spaces in patients, is a prime example. As engineering principles are better understood and surgical and prosthetic components are made more reliable, the resulting successes are astounding.
Fixed all-ceramic implant prosthetics are quickly becoming a viable option for restoration of edentulous patients. These esthetic, functional, and stable devices provide increased chewing ability, exceptional wear resistance, and better speech due to their minimal palatal coverage.1 As material availability and computer technology have improved, allowing dentists to mill precise and esthetic prostheses, the conventional hybrid has evolved into the solid zirconia bridge (eg, BruxZir®, Glidewell Laboratories, www.glidewelldental.com).2 The highly esthetic final result can be screw-retained or cemented over custom-aligned abutments and resembles a conventional bridge more than a conventional denture. In the author's experience, patient response has been extremely positive in every aspect.
Dentists' diagnostic treatment planning is limited by the viable anatomy presented. Large maxillary sinuses may inhibit placement of dental implants in the posterior maxilla without more involved surgical intervention such as sinus augmentation procedures. Proper engineering of the final prosthesis requires well-thought-out implant position and number. Arch form is considered to maintain long-term stability.3 The advent of cone-beam computed tomography (CBCT) diagnosis has aided the practitioner in determining the type, number, position, and angulation of potential implants.
A 48-year-old white woman presented to the author's office with some maxillary teeth that were functionally compromised with poor long-term prognoses. Her transitional maxillary removable appliance was difficult to wear and did not provide a positive quality of life.
The plan was to stage her restoration and the remaining non-restorable maxillary teeth were atraumatically removed and a conventional maxillary complete denture was fabricated. After a 4-month period, the realization was made that the denture was not acceptable long term, as the patient preferred a fixed option. We then diagnosed and planned for a six-implant retained fixed prosthesis. The maxillary sinuses were rather large in the posterior, so the implants were digitally planned for ideal function and esthetics.
Planning and Implant Placement
A preoperative CBCT scan (i-CAT, Imaging Sciences International, LLC, www.i-cat.com) was taken to help determine the potential positioning of dental implants and evaluate the significant anatomy, such as the maxillary sinus, as well as the horizontal and vertical bone available (Figure 1). Per the diagnosis, the remaining maxillary teeth were scheduled to be surgically and atraumatically removed, and immediate implants were to be placed. Immediately following extraction of the remaining maxillary teeth, an immediate complete denture was fabricated and seated (Figure 2).
Figure 3 illustrates the CT diagnosis and proper positioning of six maxillary dental implants within the viability of the existing anatomy using software (Invivo 5, Anatomage Dental, www.anatomage.com). Implants (3.7-mm diameter Glidewell Inclusive tapered implants) were strategically placed essentially parallel and away from the sinus areas in the edentulous maxilla as determined by CT planning. A surgical guide was created to allow for initial depth determination. Subsequent increase in diameter of the surgical burs created the osteotomy site for the implants. For this patient, implants were positioned in the edentulous areas of position Nos. 4 through 6 and 11 through 13. They were torqued to 25 Ncm, flat cover screws were placed, and the existing maxillary conventional complete denture was seated. A Mucopren® Soft liner (Kettenbach, www.kettenbach.com) was used to condition the tissue during the 4-month integration period.
After the healing period, the arch is examined prior to exposing the flat implant-healing abutment. The healthy tissue responded well to the Mucopren Soft liner, which was functional during the entire 4-month period (Figure 4). After integration, the implants were exposed using the DEKA Smart CO2 laser (Implant Direct, www.implantdirect.com) to minimize tissue damage.
Impression and Seating
Open-tray impression copings are placed within the internal hex of the six implants (Figure 5). The long yellow sleeves Glidewell Laboratories provides with its open-tray impression copings prevent any material from engaging the inside of the seating screws. The initial impression was completed using a medium-body flowable material around the dental implants along with a heavy body putty material (Kettenbach) (Figure 6). This firm polyvinylsiloxane material provides a reliable tool to create the initial implant cast.
Conventional denture techniques using bite rims establish jaw relations including vertical dimension of occlusion and centric relation. Denture teeth were set to please the patient's desired shade and tooth arrangement for esthetics and speech function. The clinician and patient approved the wax try-in.
An important next step in this process is the fabrication of a verification jig. This tool is created by the technician from the initial master cast and then numbered and sectioned and ensures a passive fit of the final prosthesis.
The acrylic pieces of the section jig (Figure 7) were seated using titanium cylinders, which passively rest into the implant body intraorally. Pieces not in contact can be luted together with an acrylic resin (eg, PATTERN RESIN™, GC America, www.gcamerica.com) or similar material.