Inside Dental Technology
February 2013, Volume 4, Issue 2
Published by AEGIS Communications
The Denture Setup
Obtaining perfect occlusion in less time
Quick quality can be achieved! This article documents how to efficiently set full upper/full lower dentures in the laboratory to yield finished appliances with ideal function.
The patient was a 63-year-old woman with existing dentures needing replacement due to substantial wear and very poor occlusion. As the patient was already wearing dentures, we sought her input as to her “likes” and “dislikes” regarding her current appliances. She felt that her existing dentures had always affected her ability to enunciate clearly. When we evaluated her current dentures, we noted that the teeth had not been set to the correct anatomical landmarks and guidelines for occlusion, and that the arches were constricted. The teeth were set lingual to the ridge instead of directly over the ridge. Also, the plane of occlusion was too low and slanted distally. The dentures were unevenly worn, indicating that the bite may have been off or the occlusion may have been inaccurately set. To solve her issues, our objectives in fabricating new appliances for this patient were to: properly analyze the models, adhere to the anatomical landmarks and guidelines, and provide precise functional occlusion.
After final impressions were taken, the first step was to analyze the lower model. The retromolar pads were outlined and a line was drawn two thirds of the way up the retromolar pad in a horizontal fashion (Figure 1). This represented the plane of occlusion. No lower posterior teeth were to be set above this line. We drew a line on the crest of the ridge, which served as a guide for setting the lower posterior teeth. Then baseplates were made with occlusal rims placed directly over the line drawn on the crest of the ridge. Records were taken and the case was mounted, making certain that the plane of occlusion lined up with both the notches at the back of the articulator and the pin on the front of the articulator.
For tooth selection, we chose the Veracia SA Anterior and Posterior Teeth, a line of semi-anatomical teeth consisting of a micro-filled hybrid composite reinforced with layered glass for excellent esthetics, long durability, and exceptional bonding strength with the denture base. The anterior teeth were set according to the contoured occlusal rims furnished by the clinician. The two upper centrals were placed in the rim so that the midline and the incisal edge touched the pin (Figure 2). Then the remaining upper anterior teeth were set. Starting with the two lower centrals, the lower anterior teeth were placed. We set them with a 1- to 2-mm overbite and overjet, though this may vary based on preference. The remaining lower anterior teeth were set making certain there were no interferences in protrusive and lateral movements (Figure 3).
We chose the matching posterior mold to set the lower arch. From the Veracia SA line, we selected the Veracia SA Q3 PACK, a distinctive tooth placement system that consists of four individual posterior teeth set into an occlusal template for each side of the arch to facilitate a quick, precise setup. The template comes notched at the mesial of the first bicuspid (Figure 4). This notch was designed to sit on the distal of the cuspid (Figure 5). The template was pressed into the wax with the line on top of the Q3 PACK placed directly over the center of the ridge and the distal occlusal of the second molar not extending above the line drawn two thirds of the way up the retromolar pad (Figure 6). We rechecked the placement, making certain that the template tab portion of the Q3 PACK was level with the occlusal plane. We then flowed wax on the buccal and lingual surfaces of the posterior teeth to hold them in place. We repeated the procedure on the opposite side of the arch. Then we confirmed that both template tabs were level with one another (Figure 7). We released the templates simply by pressing down on the lingual of the template tab and lifting up on the buccal surface of the template (Figure 8).
The Q3 PACK templates are a huge time saver. It literally takes about 15 seconds to set each of the lower quadrants, and the teeth are set into the perfect buccal alignment, Curve of Spee, Curve of Wilson, and long axis of the teeth. For the upper posterior teeth, we used a Veracia SA 1x8 card. The upper opposing posterior teeth dropped easily into place without any adjusting or grinding because of the perfect alignment of the lower posterior teeth. In less than half the standard setup time, we achieved perfect occlusion including working, balancing, and protrusive movements (Figure 9).
If it is your preference as a technician to set the upper posterior teeth first, Veracia SA offers an upper Q3 PACK. These templates would be set to each side of the upper arch following the same guidelines described above, and then a standard 1x8 Veracia SA card would be used to set the lower posterior teeth.
Our objective as technicians should be to replace what the patient originally possessed in terms of teeth, gums, and bone (Figure 10). In the fully edentulous cavity, much of this has been lost over time. This patient’s problems with clear enunciation were solved by placing the teeth in the anatomically correct position to aid phonetics. The perfect occlusion will help her to retain the dentures in the mouth and will provide better function in the working and balancing movements. The teeth we chose will provide the patient long-lasting, beautiful esthetics. In a very efficient time span, we have produced a result most satisfactory to the patient (Figure 11).
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Disclaimer: The preceding material was provided by the manufacturer. The statements and opinions contained therein are solely those of the manufacturer and not of the editors, publisher, or the Editorial Board of Inside Dental Technology.
About the Author
Jim Collis, CDT is the owner of Collis Prosthodontic
Laboratory (www.collislab.com) in Mount Prospect, Illinois.