Читать книгу Fundamentals of Fixed Prosthodontics - James C. Kessler - Страница 67

The medial pair of clamp thumbscrews on the top or backside of the upper frame of the articulator are loosened slightly. Both condylar guides are set at 0 degrees (Fig 5-28). The lateral translation clamp screws on the forward aspect of each condylar guide are loosened, and the immediate lateral translation controls are set at their most open position (Fig 5-29). The incisal guide pin is raised so that it will not touch the plastic incisal stop in any position.

The upper frame, with cast attached, is inverted, and the right lateral interocclusal record is seated on the teeth of the maxillary cast. The teeth should seat completely in the wax indentations. The upper frame is held in the left hand, and the right condylar element is placed in the right condylar guide. The teeth of the mandibular cast are gently positioned in the indentations of the wax record. They must be seated completely. The articulator is supported in this position with one hand on the right side. The left condylar element will have moved downward, forward, and inward. It is not touching the condylar guide at any point (Fig 5-30).

Fig 5-30 With the right lateral interocclusal record in place, the left condyle does not contact the superior wall (a) or the medial wall (b) of the guide.

Fig 5-31 The condylar inclination is increased until the condyle contacts the superior wall of the guide.

Fig 5-32 The medial wall of the guide is moved (a) until it contacts the condyle (b).

The inclination of the left guide is set by releasing its clamp screw. The guide is rotated inferiorly until the superior wall again touches the condylar element (Fig 5-31). The holding screw is tightened. Mandibular lateral translation is accommodated by releasing the lateral translation clamp screw and sliding the lateral translation guide laterally until it touches the medial surface of the condylar element (Fig 5-32). The clamp screw is retightened. The right condylar guidance is set by using the record for the left lateral excursion and repeating these steps.

Once the lateral interocclusal records have been made for the diagnostic mounting and the articulator has been set, the data is recorded on the patient’s information card. On the patient’s casts, the correct articulator settings for each side are marked. For example, a condylar inclination of 40 degrees and a lateral translation of 0.3 mm would be recorded as 40/0.3. When teeth are prepared at a future date and working casts are mounted on the articulator, it will not be necessary to make new lateral interocclusal records. The recorded information from the diagnostic mounting can be used to set the instrument.

Fig 5-33 The guidance provided by anterior teeth can be recorded in acrylic resin in the dovetail incisal block.

Fig 5-34 The incisal guide pin is 2 to 3 mm posterior to the tip of the retaining screw.

Fig 5-35 Tray resin is placed in the dovetail incisal block.