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At least 19 recordsLinked to original sources
PubMed1977

Biologic laws governing functions of muscles that move the mandible. Part II. Condylar position.

A model to quantify muscle response to occlusal contacts is useful in developing an understanding of the mechanism by which the occlusion programs muscle function. A knowledge of how the occlusion programs muscle function enables the dentist to develop manipulative skills of the mandible which are necessary for diagnosis and effective occlusal treatment. This article presents complicated neuromuscular responses (reflexes) to occlusal contacts in an oversimplified way and with analogies so that the clinical significance of these neuromuscular reflexes in diagnosis and treatment can be more easily understood.

Biomechanical Phenomena↗
PubMed1978

[The centric relation. IV. Variations in condylar positions according to the methods of measuring centric relation and to the patient's clinical type].

When recording and transferring centric relation onto an articulator errors can be minimized by proper use of dental materials. Remaining errors may be due to either the patient or the clinician. 3 recording techniques (Lucia, Dawson, Ramfjord) are being tested by 2 operators on 12 patients. In order to get a proper centric relation one must not rely upon a technique of taking it but rather on an adequate clinical evaluation of the TMJ at that moment. The role of inadequate intermaxillary relationship upon painful TMJ syndroms cannot be underestimate.

Adult↗
PubMed1978

Treatment prostheses in TMJ dysfunction-pain syndrome.

Various types of acrylic resin therapeutic prostheses commonly used in the treatment of TMJ dysfunction-pain syndrome were described. Each design was related to recent data concerning optimum condylar positions in the fossae, the physiologic condylar suspension system, and individual treatment objectives for repositioning the mandibular condyles. For example, alteration of the vertical dimension of occlusion is a popular treatment procedure that is empirical in nature and is usually used without TMJ radiographs or a differential diagnosis. It can violate the physiologic requirements of the interocclusal distance or the speaking space and does not necessarily move the condyles forward as has been commonly thought. The dangers of empirical treatment procedures for a multicausal dysfunction syndrome have been pointed out. An example was cited where the mandible was moved forward for a long period of time with a repositioning prosthesis; this produced pathologic TMJ remodeling and continued pain. It was recommended that specific mandibular repositioning be based on the type of condylar displacement observed on the radiographs. Sometimes the condyles should be retruded, and other times they should be repositioned anteriorly or occasionally inferiorly on one side. Long-standing use of any acrylic resin repositioning prosthesis is contraindicated, particularly without close supervision. Acrylic resin anterior bite plates (with a minimum opening of 1 mm) were recommended for the relief of acute trismus or intractable pain. Usually the prosthesis is used in conjunction with heat and drug therapy. This type of prothesis can also be utilized to deprogram the muscles when a strong habit of eccentric occlusion develops as a result of missing teeth. (This should be confirmed by TMJ radiographs.) Occasionally atypical pain is present and a differential diagnosis can be established between TMJ dysfunction or neurologic etiology by the physiologic response to bite plate therapy. When it is necessary to reposition the mandibular condyles anteriorly the occlusion is adjusted to provide the planned anterior movement without increasing the vertical dimension of occlusion. A temporary acrylic resin prosthesis is used to retrain the muscle programming to the anterior therapeutic mandibular position. When the symptoms are relieved and the corrective condylar position is confirmed with TMJ radiographs, a more permanent repositioning prosthesis is made. The treatment of TMJ dysfunction-pain syndrome should be based on documented data including the pain history, TMJ radiographs, condylar position in the fossae, electromyographic evidence, and occlusal analysis. This information will help determine if the patient's centric relation is functional or dysfunctional and will indicate the recommended treatment procedures.

Acrylic Resins↗
PubMed2026

Assessment of temporomandibular joint space changes after orthognathic surgery in skeletal malocclusion patients: a systematic review.

PURPOSE: To interpret postoperative changes in temporomandibular joint (TMJ) joint space dimensions and condylar position following orthognathic surgery in patients with skeletal malocclusions, and to determine whether reported alterations represent clinically meaningful displacement or physiological adaptive remodeling. MATERIALS AND METHODS: A comprehensive search of PubMed, SCOPUS, Web of Science, EBSCOhost, and Cochrane Library was performed to assess pre- and postoperative TMJ changes using three-dimensional imaging. Joint spaces including anterior (AJS), superior (SJS), and posterior (PJS) and condylar morphology were evaluated. Methodological quality was appraised using the Joanna Briggs Institute (JBI) checklist. Due to methodological and clinical heterogeneity, findings were synthesized narratively with attention to malocclusion type and surgical movement. RESULTS: A total of 16 studies consisting 628 patients undergoing BSSO, Le Fort I osteotomy, vertical ramus osteotomy, or bimaxillary surgery were included. Most studies reported minor, adaptive postoperative changes in AJS, SJS, and PJS. Class II patients showed more consistent increases in AJS/SJS, whereas Class III patients demonstrated variable posterior or anterior remodelling depending on surgical movement. Volumetric analyses revealed region-specific adaptations without significant condylar displacement. Postoperative temporomandibular disorder symptoms were infrequent, and no consistent evidence supported detrimental TMJ effects attributable to surgery. CONCLUSION: Postoperative TMJ joint space changes after orthognathic surgery primarily represent physiological adaptive remodeling rather than pathological condylar displacement, with reported variability driven by malocclusion type, surgical movement, fixation method, and imaging protocol. Recognizing these predictable patterns is essential to prevent overinterpretation of postoperative imaging and to improve clinical assessment through standardized three-dimensional and long-term evaluation strategies.

Humans↗
PubMed1978

Laminagraphic study of mandibular condyle position when recording centric relation.

Laminagraphs were made of each temporomandibular joint of 20 subjects (1) with the mandible forcefully retruded to centric relation and (2) with the mandible positioned by a closing force while an anterior guidance prosthesis was being used. The radiographs were compared by measurements of condylar position; results indicated the condyles to be significantly more superior in the glenoid fossa when anterior guidance was used. The difference in anterior-posterior positioning of the condyles appeared to occur randomly. Measurements of the joint spaces with the mandible in centric relation using anterior guidance indicated that mandibular condyles were not centered in the fossae. There seemed to be a range in the size of the space that could be considered normal.

Dental Occlusion↗
PubMed1979

Centric relation. Its effect on occluso-muscle harmony.

The most common cause of pain in the region of the temporomandibular joint is occluso-muscle imbalance. This results most often from disharmony between the articulation of the teeth and the centric relation of the condyles. Muscle tenderness of palpation indicates that muscle is involved. An examination must then be done to determine the cause of the muscle tenderness. Before the condyle-occlusion relationship can be evaluated, an accurate centric relation must be determined and verified. The condyles are in centric relation when they are in the most superior position possible in the fossae. From that apex of force position, the condyle can travel neither forward nor backward without moving downward. This position can be located with careful bilateral manipulation and then verified if it can resist firm pressure with no tension or tenderness. Until this correct centric relation is located and verified, it is not possible to properly evaluate the occlusal relationship to the temporomandibular joints. If the occlusion is harmonized to a centric related condyle that can resist firm pressure with pressure with no discomfort, there will be no reason for the muscles to protect either the teeth or the joints. If an occlusion is adjusted to a malrelated condylar position, the occluso-muscle imbalance will be perpetuated and often intensified. Centric relation is the starting point of occlusal contact. Incline interferences in excusive movements must also be eliminated and the occlusion must be harmonized to the envelope of function for each patient. If centric relation is not properly located, occlusal interferences will remain regardless of what procedures are used to record or adjust excursive movements.

Dental Occlusion↗
PubMed1978

[The condymeter].

The condymeter serves for the technical measurement of condylar displacement where the usual condylar position (habitual intercuspidation) is used as a relative constant. Technical fitting and calibration of the machine with the commercially available SAM-Articulator System ensures its time-saving use in diagnosis and and therapy of diseases of the temporo-mandibular joint and the neuromuscular system.

Dental Articulators↗
PubMed1977

Condylar fractures of the mandible. III. positional changes of the chin.

Positional changes of the chin (symphysion = sy) following unilateral condylar fractures of the mandible were studied in 21 children and 20 adults by means of repeated radiographic examinations. On each occasion and for each individual the actual position of the sy was related to an estimated normal position. In those children in whom the remodeling processes in the temporomandibular joint (TMJ) resulted in normal skeletal relation, the result of the subcondylar fractures seemed to be a deviation of the sy towards the nonfractured side. In cases of condylar head and neck fractures a deviation towards the fractured side frequently occurred. In four of the five children in whom normal skeletal relation in the TMJ was not obtained, the sy deviated towards the condylar fracture side. In the majority of the adulsts, a deviation towards the condylar fracture side occurred irrespective of the level of the condylar fracture.

Adult↗
PubMed1978

Anterior guidance--the key to successful occlusal treatment.

1. The occlusion of the anterior teeth is the key to developing and perpetuating an "ideal" occlusion. 2. The anterior teeth protect the posterior teeth by disoccluding them in eccentric positions, and the posterior teeth protect the anterior teeth by receiving most of the forces of closure in centric position. 3. The anterior guidance is a result of both anterior tooth position and condylar border movements; both factors must be considered in the creation of an anterior guidance.

Dental Occlusion↗
PubMed1977

Anatomic and clinical evaluation of the relationship between the temporomandibular joint and occlusion.

An anatomic and clinical investigation of condylar remodeling; the position of the condyle in centric occlusion; and the relationships of these two factors to each other and to the features of the dentition are reported. Two groups of 100 adult crania were examined. The first group had complete or partially edentulous arches. In the second group, the dentition was complete and there were various degrees of abrasion. In addition, clinical and tomographic data were obtained from 70 patients with temporomandibular joint pain-dysfunction syndrome. Occlusion was also studied by intraoral registration of the gothic arch and by mounting the casts on an articulator in 40 patients. Comparison of the data made it clear that occlusal conditions determine the course of condylar remodeling and lead to marked changes in shape of the joints. Occlusal disorders are also responsible for condylar displacement (noted in 51.4 per cent of patients), which, in turn, may be the cause of typical reshaping of the joint. These findings cast doubt on the proposition that the gnathologic determinants (particularly centric relation) are never changed in the course of time.

Adolescent↗
PubMed1977

Phosphomonoesterases in growth cartilages of the rat.

Epiphyseal plate cartilage, epiphyseal cartilage, synchondroseal cartilage and mandibular condylar cartilage were studied morphologically and histochemically in 14 days old rats. Ordinary decalcified paraffin sections were stained with hematoxylin & eosin, van Giesons connective tissue stain, or toluidine blue, and used for morphological studies of the different cartilaginous structures. Undecalcified cryostat sections were used for demonstration of acid and alkaline phosphatase. The enzyme activity was tested for at regular intervals during incubation from 15 sec to 120 min. The morphologic study revealed that a marked similarity of construction exists between epiphyseal plate cartilage and synchrondroseal cartilage. The construction of epiphyseal and condylar cartilage differ from that of the other two structures and also differ mutually. With small variations the reaction for both alkaline and acid phosphatase was found to be identical in the zones of erosion, hypertrophy and maturation of the four structures. Intercellularly, acid phosphatase is present in all zones in the synchondroseal and the epiphyseal plate cartilage, while in the epiphyseal and condylar cartilages it is only present in the zones of erosion, hypertrophy and maturation. The identical reaction for acid phosphatase in the epiphyseal and the condylar cartilage is thought, in all likelihood, to be accidental. When kinetic conditions are taken into account, epiphyseal cartilage seems to react like epiphyseal plate and synchondroseal cartilage, while the condylar cartilage takes up an exceptional position among growth cartilages.

Acid Phosphatase↗
PubMed1977

Operational definitions of mandibular morphogenetic and positional rotations.

A material of 30 patients with metallic implants was used in a longitudinal study, based on lateral headplates, of the mandibular rotational pattern. The complexity of the rotational phenomenon in the mandibular rotation has necessitated the proposal of some operational definitions: morphogenetic and positional rotations of the mandible. A relationship has been established between the variation of the gonial angle and the variation of both morphogenetic and positional rotations of the mandible. A relationship has been established between the variation of the condylar growth direction and the variation of both morphogenetc and positional rotations of the mandible: this relationship is the strongest when the morphogenetic rotation of the corpus is considered.

Dental Implantation↗
PubMed1979

[Therapeutic immediate denture, class II].

Without posterior support and because of dysfunction many people have very loose joints: their condyles are in a most retruded and downward situation. The occlusion cannot be stable in this relationship. The most retruded clinical position should not be used for prosthetic restoration. We must establish a therapeutic centric occlusion more anteriorly without increasing the vertical dimension. The amount of anterior condylar repositioning is determined by viewing the original TMJ tomographs. The position and the orientation of a normal occlusal plane can only be accurately determined by cephalometric analysis. This good occlusal scheme programmes the muscle coordination and maintains the anterior mandibular position.

Activator Appliances↗
PubMed1978

[Geometric-mathematical analysis of errors during transfer to the articulator and their practical consequences. II].

With the aid of a computer faults are examined which result in the occlusal surfaces when several articular parameters are simultaneously wrongly applied in laterotrusion. The calculations which are derived from the geometrical relations of the Dentatus articulator refer to a circular field of 3 mm radius on a molar tooth. Vertical deviations, which are caused by faulty setting up of a preferred articulator size, evidently depend on the angle of the joint on the balancing side and depend on the working side on the sagittal position of the model in relation to the condylar axis and on the length of the condylar axis. In the most unfavourable case, errors of the order of 1.3 mm on the balancing side and of 0.75 mm on the working side were demonstrated. As regards horizontal deviations, all articulator sizes were shown to be independent of one another. The effects of faulty setting up on periodontal strain is presented in a practical example.

Computers↗
PubMed1977

Posterior unilateral condylar displacement: its diagnosis and treatment.

The treatment procedure for posterior unilateral condylar displacement has been described. An acrylic resin repositioning prosthesis may be used to decrease trismus. Occlusal adjustment permits lateral freedom for mandibular movement to the opposite side which provides a dual, or a therapeutic, centric occlusion as well as the existing dysfunctional centric relation. This permits the patient's physiologic adaptive mechanism to choose between the existing dysfunctional centric relation, which resulted in unilateral condylar retrusion and pain, or a therapeutic centric occlusion which is aimed at anterior unilateral condylar repositioning. Over long period of time, muscle reprogramming produces maximum intercuspation of teeth in the planned therapeutic centric occlusion rather than in the original dysfunctional position. No explanation has been established for this phenomenon. It is important, however, to provide a technique that permits physiologic adaptability over a period of time. It should be emphasized that this is not TMJ "remodeling" but a functional change in the position of the jaw. The treatment objectives of bilateral and unilateral posterior condylar displacement are similar, but the clinical techniques are completely different. In either instance, TMJ radiographs are necessary to establish the diagnosis and treatment, as well as to document the postoperative results.

Acrylic Resins↗
PubMed1975

[Arthroplasty of the knee. Prosthesis without uni- or bicondylar hinge].

The prosthesis has two components. The femoral component is metallic surfacing the condyle and a tibial plateau in polyethylene replaces the original one. The prosthesis can be uni or bi-condylar. Operative technique has to be very precise and the position of the prosthesis needs accuracy. The advantages are: minimal bone resection, small implant harmonic action with the knee joint as a whole. 20 patients with I8 months follow up are reviewed, problems are infections and pain in the patello-femoral joint. The results on pain and walking are good. Stability depends on accurate indications.

Aged↗