Accuracy of three interocclusal recording materials used to mount a working cast.
When remaining occlusal contacts of a dental posterior quadrant have been prepared to receive complete or partial coverage restorations, it is necessary to use an interocclusal recording material to approximate the casts for laboratory mounting procedures. Inaccuracy in working cast approximation leads to occlusal discrepancies in the fabricated restorations that require correction by the dentist at the time of insertion. Traditionally waxes, impression compounds, plasters, and zinc oxide-eugenol pastes have been used intraorally to record maxillomandibular relationships. Elastomeric materials have also been advocated. Manufacturers of thermoplastic resins have recently suggested that these materials may be used with ease and accuracy for interocclusal records. This investigation measured and compared the accuracies of a thermoplastic resin, an acrylic resin, and a vinyl polysiloxane interocclusal recording material. A measuring method was developed in which a computerized axiograph was used to record positional errors in three planes, next to the posterior teeth, with the interocclusal recording materials listed.