Dentistry uses articulators to hold plaster models of the upper and lower jaws. This dental auxiliary instrument simulates the function of the human temporomandibular joint. Dental technicians make plaster models of the maxillary and mandibular dentition and mount them in occlusion in the articulator.
What is the articulator?
Dentistry uses articulators to hold plaster models of the upper and lower jaws. This dental auxiliary simulates the function of the human temporomandibular joint. Dental technicians use articulators to make customized dentures for their patients. The dental technician fixes the plaster models of the upper and lower jaw made according to the impression in the registered occlusion of the articulator. The articulator moves the fixed plaster models in relation to each other, simulating the patient’s chewing movements. In this way, the dental technicians achieve the appropriate dimension and adequate occlusal surface design. Occlusion is a central topic in dentistry. Dentistry uses this term to describe the interlocking caused by each contact between the teeth of the upper jaw and those of the lower jaw. Overall, the teeth touch each other only a few times and minutes a day, while they spend the vast majority of the time at rest. Their distance from each other is two to four millimeters. During chewing movements, the teeth of the upper and lower jaws are not in contact with each other because the food is between them. Only at the end of the chewing and swallowing process does a brief moment of contact of low force occur. If a patient exhibits a harmonious occlusal pattern, the tooth contacts are concentric. Occlusal early and pre-contacts can cause a functional disorder in the masticatory system, which the dentist detects with occlusal paper. Occlusion plays an important role in identifying craniomandibular dysfunction (CMD) and treating these dysfunctions in the patient’s masticatory system. Dentists must have extensive knowledge of dental functional theory. This field includes the geometric and biomechanical laws of the occlusal design of occlusal surfaces and the functioning of the temporomandibular joints. At this point, articulators are used as auxiliary dental instruments to represent the complex neuromuscular relationships and the interaction between temporomandibular joint position and occlusion.
Function, effect, and goals
Dentistry recognizes two super-groups: Acron and non-Acron articulators. Acron articulators adopt the natural movement principle of the human jaw, while non-acron articulators represent this movement process in an atypical way to the natural movement process. Three different articulators are distinguished: 1) occludator, 2) average articulator and 3) individual articulator, which is available in partially and fully adjustable versions. The three articulators differ in terms of the accuracy with which they reproduce the real movement conditions of the human temporomandibular joint. Occludators reproduce the simple hinge movement, also known as “tilt-fold”. Exclusively by means of mean value and full value articulators, dental technicians are able to simulate the real and individual jaw movements of patients. This dental technology is essential for the fabrication of high-quality dentures and bite splints. Thus, the articulators for setting up denture teeth enable a detailed representation of the temporomandibular joint trajectories. The simplest way for dental technicians to simulate the complete movements of the mandible is through the individual fully adjustable articulator, including the reproduction of the lifelike movements. Dental technicians record these jaw movements beforehand with a pantograph. This term has its origin in the Greek language and means “universal recorder”. This precision device is also known as a transfer arch, which makes an extraoral and three-dimensional registration of the horizontal and vertical limit movements of the human temporomandibular joint by means of a facial arch. In doing so, the device includes the canine movements with and without tooth guidance in its recordings. Based on these recordings, the dental technicians reproduce and adjust the mandibular movements in an articulator in a further step.The dental technicians are supported by the facebow, which makes this process possible. This is applied to the patient. It transfers the individually measured parameters to the articulator and determines the position of the upper and lower jaw in relation to the temporomandibular joint and skull base. The dental technician positions the facebow on both sides of the external auditory canal and on the protruding frontal bone above the root of the nose (glabella). In the next step, the dental technician presses the bite fork against the occlusal surfaces of the mandibular teeth. It is then locked and screwed to the facebow by means of a joint. This completes the registration process. The facebow with linkage and bite fork is then attached to the articulator and the upper jaw model is articulated on the bite fork in the next step. The mandibular model is fixed and articulated in the same way as the maxillary model using a DROS centric registration. The transfer of the temporomandibular joint trajectories (axiography) measured individually on the patient by articulators forms the indispensable basis for a complete denture restoration in the restorative science of dentistry.
Risks, side effects and dangers
Occlusion plays a far more important role in dental medicine than dental aesthetics, as dysfunctions in the temporomandibular joint can have lasting effects on patients’ overall health. When using articulators, dentists pursue the goal of transferring the patient’s oral situation as faithfully as possible to the articulator in order to detect occlusal disorders and to enable the patient to achieve healthy occlusion by means of therapy. Articulators are used for diagnostics regarding the position and movement of the opposing dental arches and for the fabrication of lab-fabricated restorations. The possibilities are manifold, from inlays to dentures. The handling of these precision devices has to be learned. When using the articulators, malfunctions in the mechanical processes can occur if they are not performed correctly on the patient, which must be avoided. Acron articulators can easily fall apart while the upper part lifts off condylar balls unnoticed during the closing process. This distraction can occur in the case of posterior pre-contacts. This possibility must be taken into account especially when grinding in dentures and restorations in the articulator. Correct handling is achieved by strictly holding the articulations together and a sensitive closing procedure. Other groups of articulators also exhibit a similar constellation of risks.
