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ARTICULATORS. ARTICULATORS. They are a mechanical device that stimulates the movement of the mandible. Principles of using articulators. The mechanical replication of the path of movement of the posterior determinants , the TMJ .
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ARTICULATORS They are a mechanical device that stimulates the movement of the mandible
Principles of using articulators • The mechanical replication of the path of movement of the posterior determinants , the TMJ . • Then an instrument are used to fabricate a fixed or removable dental restoration .
Classification of articulators • According to the accuracy of reproducing the movement of the mandible • According to the shape
(1)Non-adjustable articulators • Only a hinge opening • Distance between the teeth and axis of rotation is shorter • Affect the morphological feature • Lead to : restoration with occlusal discrepancies which may lead to neuromuscular disorder Simple Hinge articulator
According to the movement ( 2) semi-adjustable articulators • Larger in size allow a close approximation of the anatomic distance between the axis of rotation and the teeth • Intercondylar distance Similar to that in the average patient • Adjustable condylar inclination , and incisal inclination ; • Used in most single units and FPDA • Accepted face bow transfer.
(3) Fully adjustable articulators Advantage • Most accurate.Has great accuracy in the reproduction, both horizontal & lateral inclination are adjusted according the the records taking from the patient’s mouth . • Used for extensive treatment Disadvantage • Expensive • Required high skills & understanding. • Required a lot of time to represent 3 records:
According to the shape 1_arcon articulator • Condylar element are placed on lower member ,the mechanical fosse are placed in the upper member simulating the position of glenoid fosse in the skull
According to the shape 2_nonarcon articulators • The condylar element are placed in the upper member while the mechanical fosse are placed in the lower member • Arcon type are widely used in fixed restoration because their accuracy and easy with which they disassemble to facilitate the occlusal waxing
To evaluate the patient occlusion , we have to place the diagnostic casts in the articulator in the same relationship to the TMJ as exist in the patient . This is done by using face bow to mount the maxillary cast and interocclusal wax record to mount the lower cast .
Face bow • It is an instrument used to record the position of maxillary arch relative to opening and closing • Two types : 1_arbitary 2_kinematic
Types of face bow (1) Arbitary Type: • Whip mix face bow • Denar face bow • Hanau face bow
Examine the casts and the articulators • The condyles is in the retruded position in its condylar track mechanism (against the posterior and superior walls of the condylar guide • Both casts are completely seated in the interocclusal record • Mounting stone is securely attached to both casts and mounting plates