made of a visible

Craig Passon, DDS, MS,* and Marvin University





of Colorado, School of Dentistry, Denver, Colo.

The treatment of complex fixed partial dentures and multiple-unit castings often requires intermediate procedures for the transfer of tooth relationships from the patient’s mouth to the working model. Transfer copings used when multiple teeth have been prepared and the individual dies require accurate seating on the working cast. Transfer copings are commonly made of autopolymerizing acrylic resins. The use of these materials may present difficulty. A technique for making transfer copings by use of a visible light-cured resin is presented. (J PROSTHET DENT



ransfer copings are used when multiple teeth have been prepared and the individual dies require accurate seating on the working cast. Transfer copings can also be

used to obtain interocclusal centric relation recordings and to maintain or verify interocclusal distance. In addition, they can be used to judge the quality of the impression procedure by comparative evaluation of the die and tooth for dimensional accuracy and margincompleteness.iTransfer copings are commonly made of autopolymerizing acrylic resins. Generally, methyl methacrylate-type resins have been used although ethyl methacrylate resins are also available for this purpose. The use of these materials may be a problem. Recently, a visible light-cured urethane dimethacrylate (Triad, Dentsply Int., Inc., York, Pa.) became available. Although this material was originally designed for denture relining, modification, and repair, other uses such as provisional restorations have also been intr0duced.z In addition, Triad resin has been used for baseplates, impression trays, and single-tooth addition to partial dentures. This article describes a technique for making transfer copings of Triad visible light-cured resin.

TECHNIQUE Triad resin was first made available in ropes and sheets of denture-pink color. Subsequently, a blue color for custom trays and baseplates and ivory (tooth-colored) shades for provisional restorations and denture repair were introduced (Fig. 1). Blue Triad resin is best suited for transfer copings. Its contrast with the ivory color of teeth and pink color of gingiva provides for easy evaluation of full coping seating and marginal accuracy. The technique serves well for stone and metal-plated dies (Fig. 2). After trimming and identification of the marBAssistant Professor, Department of Restorative Dentistry. bProfessor and Acting Chairman, Department of Restorative Dentistry. 10/l/29086


Fig. 1. A, Rope of “tooth colored” Triad resin. B, Sbeet of blue Triad resin. gins, the die can be lubricated with a standard die lubricant (Die-Lube, J. F. Jelenko and Co., Armonk, N.Y.). A smallto-moderate sized increment of Triad resin is carried to the die and is adapted with fingers or a suitable lubricated plastic instrument (Fig. 3). Triad resin is a highly viscous material. If adaptation is difficult, the viscosity of the material can be reduced by warming it in 120’ to 150a F water before application to the die. It is recommende most instances half of the coping be formed at a time to assure easy removal, especially for intracoronal restorations (inlays, onlays). When appropriately shaped, the coping is light-cured for 1 minute with a standard composite resin light-curing unit (Fig. 4). Because this material is opaque, additional exposure may be necessary to cure thick coping surfaces properly. After half of the coping has been shaped and cured, it is removed from the die and inspected. If the adaptation and marginal fit of the coping is adequate, the second half is formed and cured as described. The two halves will bond to form a complete coping unit,


Aftervisualicspestion of margila aeculracy anddetermination

0% proper

fit, the


are taken

to the



anner as a~t~~o~y~e~i~i~~resin copings (Fig. ‘;:,




Fig. 6. Modified copings: A, retentive “wings” added. B, Margin modification using methyl methacrylate resin.

Initial photocuring of thick specimens can be done with conventional light-curing unit. Although thin sections of Triad resin may be adequately cured in this way (such as 1 to 2 mm thick provisional restorations), thick or highly opaque resins should be subjected to intense final photocuring. The Triad resin-curing unit emits intense collimated shielded light from quartz halogen lamps that are concentrated in the shorter blue 400 to 500 nm wavelength spectrum of visible light. This high-intensity light combined with a rotating platform results in deep polymerization of the resin.3 Uncovered cured Triad resin will, as with all light-cured composite resin systems, produce an air-inhibited layer. At times, this layer may be advantageous inasmuch as it will provide a surface for the bonding of additional light-cured or autopolymerizing resins. If, however, the air-inhibited layer is removed during trimming, the application of autopolymerizing acrylic resins to fully cured Triad resin can be enhanced by coating the surface with free acrylic resin monomer, then after it dries, coating with Triad resin bonding agent followed by the application of the autopolymerizing acrylic resin as needed. Bond strengths of Triad resin to heat-cured acrylic resins have been reported to be in the 3500 psi range.3 Free and residual monomer of methyl methacrylate resins has been implicated as the cause of allergic reactions, stomatitis venenata, and general hypersensitivity reactions in patients.4W6However, the actual cause of these reactions is not fully understood or accepteds7Triad resin is free from methyl methacrylate monomer and therefore may be a suitable substitute for transfer copings for patients who






7. Completed Triad resin transfer copings.

report or are suspected of having a sensitivity to this chemical. Triad resin is proving to be a versatile material. The fabrication of transfer copings is still another use.

SUMMARY Several fixed prosthodontic situations require the use of transfer copings. These copings commonly have been made of autopolymerizing resins. This article describe of using the visible lighbcured acrylic resin Triad for transfer copings on stone and metal dies. REFERENCES 1. Johnston JF, Phillips RW, Dykema RW. Modern practice in crown and bridge prosthodontics. 3rd ed. Philadelphia: WB Saunders Co, 19’71; 221-3. 2. Prestipino V. Visible light cured resins: a technique for provisional fixed restorations. Quintessence Int 1989;20:241-7. 3. Ogle RE, Sorensen SE, Lewis EA. A new visible light-cured resin system applied to removable prosthodontics. J PROSTHET DENT 1986; 56:497-506.

4. Fisher AA. Allergic sensitization of the skin and oral mucosa to acrylic resin denture materials. J PROSTHET DENT 1956;6:593-602. 5. Nealy ET, de Rio CE. Stomatitis venenata: reaction of a patient to acrylic resin. J PROSTHET DENT 1969;21:480-4. 6. Stungis TE, Fink JN. Hypersensitivity to acrylic resin. J PROSTHET DENT 1969;22:425-8.

7. Shafer WG, Hine MK, Levy BM. A textbook Philadelphia: WI3 Saunders Co, 1983;556. Reprint


of oral pathology.

4th ed.




Transfer copings made of a visible light-cured resin.

The treatment of complex fixed partial dentures and multiple-unit castings often requires intermediate procedures for the transfer of tooth relationsh...
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