Written by Gregori M. Kurtzman, DDS, MAGD, DICOI, and A. Burton Melton, DDS, DICOI Wednesday, 30 June 2004 19:00
Patients who are currently wearing full arch removable prostheses may present requesting new dentures. The process may be simplified and the number of appointments decreased by using the current dentures as custom trays for master cast construction. The dentures may be duplicated quickly in the office to fabricate custom trays. When time is essential to provide the new dentures, the duplicated dentures can be ready for impression-taking in about 1 hour.
The patient, a 49-year-old white female, presented requesting a duplicate set of dentures. She expressed that she was satisfied with the present dentures but wished to have a duplicate set fabricated.
Impressions and Master Model Fabrication
The patient’s current full maxillary and mandibular dentures were duplicated with a Lang denture duplicator (Lang Dental) using alginate (Tropicaligin; Zhermack). Upon setting of the alginate, the duplicator was opened and the denture removed. A self-cure acrylic (Jet Acrylic; Lang Dental) was mixed and poured into the duplicator. The duplicator was closed and immersed into a bowl of hot water to accelerate set of the acrylic.
Fabrication of the Record Base
|Figure 1. Master casts are fabricated based on duplicates of the current dentures and mounted in occlusion.||Figure 2. The mandibular baseplate is placed on the articulator ready to have teeth set to occlude with the maxillary duplicate denture.|
|Figure 3. An acrylic bur is used to bevel the flanges with a chamfer.||Figure 4. Denture tooth cage for removal of wax residue.|
|Figure 5. Knife edge diamond creating divergent tissue side cuts in the denture tooth.||Figure 6. Collar diamond creating a circumferential groove on the denture tooth.|
|Figure 7. Setup Eclipse resin being placed on the cured baseplate with an electric spatula.||Figure 8. Setup begins with a mandibular central incisor.|
|Figure 9. Maxillary and mandibular teeth set on baseplates with Setup resin.||Figure 10. Occlusal view of the maxillary denture setup. Setup resin is confined to holding the denture teeth to the baseplate only.|
After placement of the posterior palatal seal, the master cast was brushed with Al-Cote (DENTSPLY Trubyte) to seal the cast and prevent resin penetration into any microdefects within the surface of the stone cast. To facilitate adaptation of the Baseplate resin, the master cast was placed in the conditioning oven and allowed to reach 55ºC. A package of Baseplate resin was opened, placed on the warmed cast (convex side toward the cast), and placed back into the conditioning oven to soften the material. The model was removed from the oven and molded with finger pressure to allow the Baseplate resin to melt into the master cast and form the denture base. Air Barrier Coating (ABC; DENTSPLY Trubyte) was brushed over the entire surface to eliminate an air-inhibited layer on the surface of the resin.
Figure 11. Occlusal view showing Eclipse Contour resin has been applied to the exposed baseplate.
|Figure 12. A hot-air gun is being used to smooth the Contour resin.|
|Figure 13. The electric spatula is used to apply Contour resin and for initial shaping.||Figure 14. Carving instruments are used to festoon the material.|
|Figure 15. Eclipse Contour material has been applied to the dentures and festooned.||Figure 16. Dentures at try-in. Note the bubblegum-like appearance of the uncured Eclipse material.|
|Figure 17. Eclipse gel being applied to the flanges of the conditioned denture prior to processing.
||Figure 18. Uncured denture in the processing unit awaiting processing.
|Figure 19. Final processed denture. Note the change in color of the base material.
||Figure 20. Finished and inserted dentures.|
Teeth were selected to match the shade and mold of the patient’s current dentures, as she was satisfied with the aesthetics. The teeth were placed in a metal tooth cage, and wax residue was dissolved in a boiling water bath (Figure 4). The lower teeth were ground to fit the baseplate. Mechanical retention is required to retain the denture teeth within the Eclipse material following final curing. To facilitate this, divergent cuts were made on the tissue side of the denture tooth utilizing the knife edge diamond in a slow-speed handpiece (Figure 5). A circumferential collar groove was made with an inverted cone diamond in a slow speed (Figure 6). An electric spatula was utilized to place Eclipse Setup material in the grooves/cuts on each denture tooth to ensure that no voids were present between the tooth and baseplate.
Completion of the Denture
The Eclipse denture setups were tried in and checked for aesthetics and phonetics. Upon approval the dentures were returned to the light-proof bags and were ready for processing. The denture was placed on the master cast and air barrier brushed over the entire surface of the final setup and cast. Air Barrier Coating must be used to prevent air inhibition, which causes staining of the air inhibited layer. It is important to achieve a smooth surface when polishing the denture, since rough, unpolished areas show slight stain retention. Eclipse provides acceptable in vitro stain resistance to both coffee and mustard when properly polished. In vitro mustard stain resistance is similar to L199. Dentures, repairs, and relines all show acceptable stain resistance.
Eclipse provides a denture material that is free of monomer (methyl, ethyl, butyl, or propyl methacrylate) for a more biocompatible product that also eliminates potential hazards to the laboratory technician during fabrication. Potential for leaching of monomer during denture use long term is eliminated, creating a more stable denture for the patient. Flasking and packing are eliminated, making processing faster and easier for the technician. Once the final denture has been approved, the denture can be processed in as little as 1 hour and 15 minutes compared to 4 or more hours using conventional methods. The “wax-like” feel of the thermoplastic material allows the technician experienced at fabrication of fixed prosthetics to use techniques they are comfortable with, thereby shortening any learning curve with the system. Labor time is greatly decreased for the technician, increasing profit and capacity.
Full arch removable prosthetics can be a challenging treatment and time consuming for the dentist. When the patient presents with an existing full arch removable prosthesis, it can be utilized to fabricate a custom tray, improving and simplifying the impression phase of treatment. The technique described affords laboratories the ability to finish and process dentures in less than 90 minutes, compared to more than 4 hours using traditional processing that involves flasking and packing. Additionally, the final processed baseplate fabricated at the initial laboratory appointment allows both the dentist and patient to feel how the final denture will fit and what retention will be present prior to final processing of the denture. Eclipse dentures are repairable using conventional materials, however the optimal repair is completed using Eclipse Baseplate resin. Reline procedures may be accomplished with any soft or hard conventional materials.
The authors would like to thank Drs. Nels Ewoldson and Gary Henkel for their help in reviewing this article.
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