An Overview Of Dental Articulators
Prosthodontics involves a good understanding of the precise fabrication of any individual prosthesis to restore occlusal harmony. They believe that the key to this harmony is the individual determination of the transverse horizontal axis, hinge axis, and the patient’s mandible
What Is An Articulator? An articulator is a mechanical device that simulates the movements of the mandible. The basic principle in the use of articulators is the mechanical replication of the paths of movement of the craniomandibular joints (posterior determinants). The articulator is then used in the fabrication of fixed and removable prosthetic restorations that are in harmony with mandibular movements. The border movements of the mandible, limited by ligaments, are highly repeatable and useful in setting the adjustments on the mechanical fossae of an articulator. The accuracy in duplicating border movements is directly related to the precise simulation of the posterior determinant of occlusion. As a result, the harmony between the restoration and the craniomandibular joints - TMJ - will be improved.
How To Get The Most Out Of Dental Articulators To achieve the highest possible degree of accuracy from an articulator, the casts mounted on it should be closing around an axis of rotation that is as close as possible to the transverse horizontal hinge axis of the patient’s mandible. The hinge axis is an important reference point because it is repeatable. It is necessary to transfer the relationship of the maxillary teeth and the transverse horizontal axis, and a third reference point from the patient to the articulator. This is accomplished with an instrument called a facebow, which records those spatial relationships and is then used for the attachment of the maxillary casts to the articulator.
Types of Articulator There are three general types of articulators, based on the accuracy with which they reproduce the movements of the mandible. 1.
A nonadjustable articulator which is at the lower end of the scale, is usually a small instrument that can reproduce only hinge opening. The distance between the teeth and the axis of rotation is considerably shorter than it is in the skull, with a resultant loss of accuracy.
2. The semi-adjustable articulator with its larger size allows a close approximation of the anatomic distance between the axis of rotation and the teeth. The radius of movement produced on the articulator will reproduce the tooth closure arc with relative accuracy. This type of articulator can be used for the fabrication of most single-tooth restorations and fixed bridge prostheses. 3.
A fully adjustable articulator - it is the most accurate instrument, designed to reproduce the entire character of border movements, including immediate and progressive lateral translation, and the curvature and direction of the condylar inclination. Intercondylar distance is completely adjustable. With this articulator, a highly accurate reproduction of the mandibular movement can be achieved. Fully adjustable articulators are used primarily for extensive treatment, requiring the reconstruction of an entire occlusion.