 Centric jaw relation records are an essential component of the materials submitted to the regional dental activity for the fabrication of various prosthodontic appliances. The proper preparation of these records is crucial to the final success of the appliances. When preparing centric jaw relation records, it is necessary to recognize that specific dentulous and edentulous situations dictate the use of specific record bases. These bases in turn dictate the appropriate methods to be employed as well as the types of materials to be used. In view of the special problems associated with receiving materials by mail, the RDA highly recommends certain materials and methods. We will discuss the materials and procedures for obtaining centric jaw relation records associated with the fabrication of fixed partial dentures and crowns. The records associated with complete dentures and removable partial dentures are discussed in the first videotape in this series. When fixed partial dentures are required, there are four different dentulous, edentulous situations that are possible. If an appliance is tooth-borne and sufficient teeth remain in both arches, records are unnecessary. It is only necessary to use witness lines or cuts to record centric occlusion at tooth contact. Here, a mandibular three-unit bridge has been prepared. An unprepared molar lies distal to the terminal abutment. Subsequently, no jaw relation record is needed. The majority of fixed prosthodontic cases fall into this category. To introduce a jaw relation record when not indicated is courting the introduction of errors. When a prepared terminal abutment is involved and natural teeth are present on the opposing arch, a trimmed occlusal wafer index is recommended. The material suggested for the index is any fine-grained auto-palmarizing resin. Once again, a three-unit mandibular bridge has been prepared. The molar preparation is the terminal abutment. The area is dried and then coated with a suitable lubricant. This protection is necessary to minimize hard and soft tissue damage from free monomer. The soft wafer is placed over both abutments and the patient is instructed to close into his habitual or acquired occlusion. The stage of resin polymerization here is critical. If the material is well into the doughy stage during closure, distortion will occur. The resin should be inserted as soon as it possesses sufficient body to be handled. The wafer is removed at initial set. Prolonged retention can cause tissue damage from the heat of exothermia common to these resins. The wafer is trimmed to eliminate contact with soft tissue and unprepared teeth. The finished wafer should retain only the cusp tips of opposing teeth and minimal registration of the abutments. The record is returned to the mouth and the registration verified. Prior to articulation, the cast must be free of bubbles and defects which would prevent complete seating of the registration. It must be emphasized that a recording of this type encompasses both abutments. It is far more stable and easier to orient than one which involves only one of two or more abutments. If prepared anterior teeth are involved and a positive anterior stop is necessary, a trimmed incisal index made of resin is recommended. This patient has sufficient teeth remaining to normally allow for hand articulation of casts. His occlusion, however, is not stable. The anterior wafer will ensure correct cast orientation. Once again, the tissues are dried, lubricated, and the wafer positioned over both abutments. Upon removal, it is trimmed and returned to the mouth for verification. The casts are checked for seating interferences prior to articulation. The trimmed wafer must show only the incisal edges of the preparation. Excessive coverage by the recording can cause fracture of fragile anterior dyes. If there is an insufficient number of teeth in the mouth for positive stops, it is suggested that auto-polymerizing resins serve as the material for the record base. The recording material can be zinc oxide eugenol paste, plaster, or modeling plastic. The situation shown here on casts makes use of the sprinkle-on-resin method. This technique is preferable to resin molded or adapted to the cast. The base has better stability, and due to its reduced overall dimensions, distortion is reduced. Any suitable zinc oxide eugenol paste is an ideal recording material. Modeling plastic or plaster are also acceptable, but due to their brittleness are susceptible to fracture during shipping. Once the recording is made, special care is given to trimming the registration. Zinc oxide eugenol reproduces extremely fine detail not shown in casts obtained with alginate impressions. Subsequently, to facilitate complete seating of casts, all but the cusp tip indentations must be removed from the recording. When recording material is utilized in obtaining the records, this material must be sufficiently rigid when set to prevent distortion during shipping. Records must not be sealed to the casts, and casts must not be sealed to each other. Please, do not send casts mounted on an articulator. If casts are mounted on an articulator prior to shipment, they must be keyed and lubricated before mounting and separated from the articulator. Both the casts and the articulator must be shipped to the RDA, accompanied by the jaw relation record. If a case must be constructed on a semi- or fully adjustable articulator, it must be submitted on a mounting ring at the appropriate relation to the hinge axis. The axis can be arbitrary or panographic. The mandibular cast and centric jaw relation record should accompany the mounting. The condylar and incisal guidance setting should be noted on the prescription form. Proper occlusion, which is established through centric jaw relation records, is a major influence on the fit and appearance of an appliance. All the procedures that we have discussed have been designed to aid the RDA in fabricating the prosthodontic appliances that will meet our patient's needs.