One clinical visit for a multiple implant restoration master cast fabrication,☆☆,,★★

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Abstract

The making of a one-piece, long-span, implant-supported prosthesis with conventional procedures frequently has difficulties associated with the accuracy of fit. This article presents a clinical and laboratory procedure for making an accurate implant working cast that facilitates fabrication of the casting on the master cast. The procedure demonstrates the process of sectioning and rejoining of the resin between the transfer copings and then pouring the impression by first joining the analogs alone with impression plaster, sectioning it, and rejoining it again to stabilize the analogs, and finally, using dental stone to pour the impression. Clinical, radiographic, and laboratory (optical microscope) measurements for one clinical implant restoration confirm the accuracy of fit of this one prosthesis made with this procedure. Its advantage is that it can allow fabrication of the final casting on the cast, thereby eliminating the clinical time necessary to obtain repetitive solder indexes, and thus minimizing inconvenience to the patient. (J Prosthet Dent 1997;78:550-3.)

Section snippets

CLINICAL PROCEDURE

  • 1.

    Seat a square transfer coping on each implant and secure it with a long screw. Confirm the seating by radiography.

  • 2.

    Weave dental floss among the square transfer copings and apply acrylic resin material (GC Corp., Tokyo, Japan) or light-cure composite with a brush or small spatula to join all transfer copings. The floss acts as a matrix for the resin.

  • 3.

    Unscrew the transfer copings and remove them from the mouth. Section the resin between each transfer coping with a thin disk and reseat the transfer

LABORATORY PROCEDURES

  • 1.

    Attach an implant analog to each impression coping embedded in polyvinyl siloxane impression material.

  • 2.

    By using a brush or cement spatula, join the apical portion of the analogs securely with impression plaster.

  • 3.

    After the impression plaster sets, section each interproximal space with a thin disk. Soak it for a few minutes in slurry water and rinse it out. Then proceed to rejoin the separations with a second mix of impression plaster (Fig. 2). Rewet the plaster before adding the new mix, otherwise

DISCUSSION

Even though the procedure that uses an open top tray and acrylic resin to splint the transfer copings is considered to be the most accurate method,16 there is usually a detectable gap observed between the implant head and the prosthesis framework. For this reason, an intraoral soldering index needs to be made routinely.

Two master casts were fabricated with the same impression, which was made by using an open tray, luting the impression copings, sectioning them, and then rejoining them. The

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Cited by (21)

  • Comparison of the accuracy for three dental impression techniques and index: An in vitro study

    2013, Journal of Prosthodontic Research
    Citation Excerpt :

    Therefore, there is improved efficiency, a reduction of chair time and greater transfer precision due to the splinting stability. If the final prosthesis is fitted on the index, then, a clinician should trust that it would most likely fit a patient's mouth [34]. This would be advantageous, since passive adaptation of the implant abutment to the framework is often difficult to achieve and to interpret in a clinical setting [35].

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aProsthodontic Resident and Graduate Student, Department of Prosthodontics and Biomaterials.

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bProsthodontic Resident, Department of Prosthodontics and Biomaterials.

Reprint requests to: Dr. Tanya Wong, UMDNJ Dental School, Department of Prosthodontics, 110 Bergen St., Newark, NJ 07103

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