【文章內(nèi)容簡介】 Bfully adjustable articulators This type of articulator can accept the following records: 1face bow record to mount the upper cast. 2centric occluding relation record to mount the lower cast. 3protrosive record, to adjust the articulator39。s horizontal condylar guidance which corresponds to the patient39。s horizontal condylar bath inclination. 4right lateral record, to adjust the left lateral condylar guidance which corresponds to the patient39。s lateral condylar path inclination. 5left lateral record, to adjust the right lateral condylar guidance which corresponds to the patient39。s right lateral condylar path inclination. Indexing the cast Indexing casts prior to mounting them on an articulator permits removal of the cast and accurate replacement to the articulator. Indexing is also important for remounting procedures made for correcting occlusal errors after curing a denture. Indexing can be acplished by placing grooves or notches, in the cast or by using remounting plates Mounting the master cast on the articulator In the process of mounting master casts on a fixed condylar path articulator the following steps should be performed: 1the upper and lower casts are prepared for laboratory remount by cutting indices on the under surface of both casts. These indices are protected by tinfoil. 2the upper and lower trial denture bases are sealed with wax to their casts, thus the upper cast, lower cast and wax rims are all attached together. The arms of the articulator to be used are lubricated with Vaseline or oil to facilate cleaning the articulator from the plaster after the case is finished. 3the incisal guide pin of the articulator is adjusted until its top flushes with the top of the upper member. 4a rubber band is placed on the articulator, extending from the lower mark of the incisal guide pin and around each condylar post support. Adjust the rubber band to form a plane that divides the space between the upper and lower members of the articulator equally Bonwell triangle 5Three lumps of modeling clay are placed on the lower mounting plate to serve as an adjustable cast support 6with the base plate and occlusion rims sealed together, place both maxillary and mandibular casts in the correct relationship on the three clay supports in the articulators .then align them until of the occlusal plane of occlusion rim is parallel to the plane established by the rubber band 7open the articulator, and paint the base of maxillary cast with a separating medium. 8mix, and add plaster to the base of the cast and to the upper member of the articulator. 9close the articulator until the incisal guide pin touches the incisal guide table and then add more plaster as needed to fill any voids. 10after the stone has set, invert the articulator, and open it. Removing the modeling clay cast supports, paint separating medium on the base of the lower cast and attach it to the articulator with plaster. 11permit the plaster to set, then remove excess plaster with a knife. Occlusion rims An occlusion rim is a wax form used to establish: 1the proper lip and cheek support (fullness of the lips and cheeks) 2the arch form, which is related to the activity of the lips, cheeks and tongue. 3the level of the occlusal plane. 4accurate maxillomandibular jaw relations . Help to determine: Avertical dimension and an estimate of the interocclusal distance. Bhorizontal jaw relations (centric occluding relation and condylar path) 5occlusion rims help to determine the length and width of the artificial teeth: Ahigh and low lip lines are used for determining the length of the artificial teeth. Bcanine line . corners of the mouth。 the distance between the canine lines determines the width of the six anterior teeth. Cthe distance between the canine line and the posterior end of the occlusion rim determines the mesiodistal width of the posterior teeth. 6position of midline of the arch for the correct placement of the central incisors. 7arrangement of the artificial teeth to the trial denture (setting up of the teeth). Base plate wax is the most monly used occluasl rim material. Compound and a mixture of the plaster and pumice are sometimes used for constructing occlusal rims. There are four basic factors that should be considered in the proper fabrication of occlusion rims, to assist the dentist and the dental laboratory technician throughout the many phases of denture construction. These factors are: relationship of natural teeth to alveolar bone:1 Since the final goal in the treatment of the edentulous patient is to provide a functional and esthetic prosthesis, the relationship of the natural teeth to the alveolar bone must be understood. The fabrication of successful replacements can be acplished in most cases only if the artificial teeth are placed in the same position that was occupied by the natural teeth they are replacing. The natural maxillary anterior teeth are inclined slightly forward of the alveolar bone. They contribute to the support of the upper lip With the canines providing support for the corners of the mouth. The mandibular incisors are also inclined forward and tend to support the lower lip. The maxillary posterior teeth are positioned slightly buccal to the alveolar ridge, when occluding with the mandibular molars。 the maxillary buccal cusps usually project 2 to 3 mm. beyond the buccal cusps of the mandibular teeth. The crowns of the lower posterior teeth are inclined inward