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PubMed1985

Tooth loss, attrition and temporomandibular joint changes in a Romano-British population.

Mandibular condyles and temporal fossae were studied in a large Romano-British collection of skulls. The size and shape of the condyles differed from those in previous populations studied. Changes in form or shape of the condyles were age-related and could be correlated to the number of teeth lost on the same side and on the contralateral side. No statistically significant correlations were seen between attrition and condylar form and surface change.

Adolescent↗

PubMed1990

The activity of 2,5-oligoadenylate synthetase, an interferon-induced enzyme, is coupled to the differentiation state of mouse condylar cartilage.

The enzyme 2,5-oligoadenylate synthetase (2-5A synthetase) is associated with the interferon system, with special reference to the differentiation process of various cell types. The present study investigated whether 2-5A synthetase is also involved in the differentiation of neocartilage in perinatal mice. The cartilage of the mandibular condyle, a secondary type of cartilage, develops relatively late in prenatal life; and consequently it was possible to obtain a relatively embryonic cartilage at a developmental stage that could be manipulated enzymatically, in order to separate and thereby obtain its undifferentiated, proliferative portion along with its more mature fraction. Immunohistochemical studies using antibodies against type I and type II collagen and cartilage-specific proteoglycans could have determined the differentiation status of various portions of the developing condyle. However, the above methodology lacks the necessary precision and accuracy to indicate subtle changes in cellular differentiation. It became evident that the activity of 2-5A synthetase was indeed different in cellular compartments that were at different stages of differentiation. In the neonatal condyle the highest level of activity was encountered in proliferating and as yet undifferentiated prechondrocytes, whereas fully differentiated chondrocytes showed a marked decrease in the activity of this enzyme.

2',5'-Oligoadenylate Synthetase↗

PubMed1981

The condyle as a stress-distributing component of the temporomandibular joint.

Even though the temporomandibular joint is loaded in function, it often arthroses under heavy use. The effects of stress to the joint are not well understood. This study utilized three-dimensional photo-elastic stress analysis to visualize the intensity and direction of stress within the mandibular condyle generated by various occlusal forces. Functional stress were shown to concentrate in the condylar neck, but were reduced within the condylar head due to its elliptical shape. Stress directions within the condyle were found to be non-preferential, varying with different mandibular positions. This supports the idea that the condyle is designed to receive light varied forces rather than heavy, cyclical unidirectional forces.

Humans↗

PubMedDate not supplied

Corticosteroid-induced enhanced mineralization in neonatal condylar cartilage.

Neonatal mice were treated with triamcinolone hexacetonide and the cartilage of their mandibular condyle was studied biochemically and histochemically. Three days following the hormonal treatment the condylar protein content decreased significantly but a marked increase was noted in the tissue's calcium and phosphate. The condylar mineralization front extended up to the chondroblastic and proliferative zones. Triamcinolone arrest cartilage cell proliferation and enhanced an atypical hypertrophy of chondroblasts. One week following the hormonal treatment the condyle revealed clear signs of weight loss and changes in its size and form. Glucocorticoids enhance the mineralization of neonatal cartilage via: a direct effect upon chondrocytic metabolic and control systems (genom) and possibly also through an indirect adverse effect upon other organ systems.

Animals↗

PubMed1979

Late effects of corticosteroid treatment on condylar regeneration in the monkey.

The mandibular condyles of immature baboons were used to study the late effects of intraarticular administration of glucocorticoid hormone on the regeneration of cartilage and bone. Analyses of blood and urine showed a distinct increase in the level of parathyroid hormone along with hyperphosphaturia. Regenerated condyles of animals treated with steroid showed lack of de novo formation of cartilage and severe changes in the newly formed bone. Fibrosis became the dominant feature in the newly formed bone marrow. The initial catabolic effect of glucocorticoid hormone was augmented by steroid-induced secondary hyperparathyroidism.

Animals↗

PubMed2000

Otic axis locator: closing the accuracy gap in cephalometrics and cast mounting.

An overview is presented of a new technique to improve the accuracy and reproducibility of earpost-dependent orientation in procedures such as cephalometric radiography and cast mounting, using a custom-molded ear canal insert to provide a stable fitted socket for more exact earpost fit. This is especially valuable in follow-up treatment and serial studies because the insert can be filed for future use on the same patient to provide identical positioning in successive registrations. Cephalometric radiography is further enhanced by the addition of a radiopaque x-ray marker deep in the canal, otherwise inaccessible, close to the bony ear canal (anatomical porion) and the mandibular condyle. This marker is also visible in all 3 cephalometric views-lateral, frontal (posteroanterior) and coronal (submental-vertex)-providing an exact common horizontal axis (Otic axis) for a three-dimensional Cartesian coordinate system of measurement.

Cephalometry↗

PubMed1984

Differential growth and healing of bones and teeth.

A series of experiments was performed in turtles, rodents, lagomorphs, dogs, and monkeys to determine and correlate differential growth and healing of bones and teeth. Vital stains, radiopaque implants in conjunction with serial radiography, autoradiography, histology, and other methods were employed. Histologic differences and rate of endochondral (tibia, rib, base of skull, and mandibular condyle) and nasal cartilaginous septal growth were noted. Similarly, differences were observed in growth between five facial sutures and also for the same suture at different times. The nasal bone side of the frontonasal suture grew about twice as fast as the frontal bone side. In the turtle shell the midsagittal suture grew faster than a transverse suture. A variety of differences in rate of appositional (and resorptive) growth were noted at different sites of the mandible and nasal bone region. Generally, there was deposition of bone along the posterior border of the mandibular ramus and resorption of bone along the anterior border. Variations in the volume of the orbital contents influenced orbital growth. Bone was highly reactive, while enamel and dentin were nonreactive, to trauma.

Animals↗

PubMed2005

Auriculo-condylar syndrome is associated with highly variable ear and mandibular defects in multiple kindreds.

We report on 20 individuals in 4 kindreds with auriculo-condylar syndrome (ACS), an autosomal dominant disorder characterized by congenital auricular clefts, mandibular condyle hypoplasia, temporomandibular joint (TMJ) abnormalities, micrognathia, microstomia, and a round facial appearance with prominent cheeks. Affected individuals have varying degrees of glossoptosis, respiratory distress, masticatory abnormalities, and malocclusion. Data from these families and those previously described suggest that this is a unique disorder with widely variable expression, including lack of obvious external anomalies in some individuals and severe ear malformations, condyle agenesis, and characteristic facial features in others. Early recognition of this condition should permit appropriate counseling and anticipatory guidance, including evaluation for reconstructive surgery and orthodontia and intervention for upper airway obstruction and sleep apnea.

Abnormalities, Multiple↗

PubMed1980

Non ossifying fibroma of the mandible. A common lesion with unusual location.

A first case of non-ossifying fibroma located in the mandibular condyle of a 20-year-old male is presented. Radiologic and histologic findings correspond in all details to those of non-ossifying fibromas of long tubular bones. The lesion's location within the condylar growth zone may strengthen the hypothesis that non-ossifying fibromas are disturbances in growth rather than true neoplasms.

Adult↗

PubMed1991

Occlusal considerations in restorative dentistry.

This article reviews the recent literature related to occlusal considerations in restorative dentistry. The major topics include the assessment and treatment of occlusal wear, the controversies surrounding treatment position of the mandibular condyles, occlusal considerations in osseointegrated prostheses, the two-way relationship between occlusal factors and temporomandibular disorders, design criteria and longevity studies in resin-bonded, fixed-partial dentures, and a potpourri of articles on other topics of interest. Five textbooks and 32 journal articles are cited.

Dental Implants↗

PubMed1990

[A complete intermediate temporomandibular joint prosthesis. Evaluation after 6 years].

Since 1983 we have inserted more than 100 temporomandibular joint prostheses. A review after 6 years allows the respective indications to be listed and the complications to be studied in 72 insertions involving 62 cases suitable for analysis. The prosthesis is a total intermediary prosthesis forming an unsealed cupula composed of 2 halves--a mandibular portion and a temporal portion. Insertion of the prosthesis requires preliminary facial nerve dissection then osteotomy of the mandibular condyle and its subsequent drilling to allow the screwing in of the prosthesis. The prosthesis was used in traumatology, in condylar and high sub-condylar fractures, in the event of failure of functional treatment, in malformation syndromes, in tumors and, finally, in degenerative pathology. 13 prostheses were removed. A study of the probable causes of complications shows a predominance of technical problems related to inaccurate positioning of the prosthesis, in that it was not placed in the axis of the condyle, or that inadequate bicortical support was present. In our opinion, these complications do not question the conception of the prosthesis but rather indicate that it is necessary to perfect the insertion technique while taking advantage of improvements in the prosthesis which are currently under study.

Ankylosis↗

PubMed2002

The effect of growth hormone therapy on mandibular and cranial base development in children treated with total body irradiation.

The aim of the present investigation was to study craniomandibular development during growth hormone (GH) therapy in nine girls and one boy, aged between 7.3 and 16 years, who exhibited pronounced growth reduction after total body irradiation (TBI) and bone marrow transplantation (BMT). Age- and sex-matched healthy children with normal dentofacial development constituted the control material. The investigation data were based on measurements made on lateral skull radiographs taken at the start and, on average, 6 months after cessation of GH treatment. The control group comprised similar longitudinal cephalographic records. The results showed that GH therapy in patients who exhibited growth retardation after TBI and BMT had only a minor effect on cranial base dimensions, probably due to the fact that the development of this area is completed at a relatively early age. The effect of GH treatment on mandibular growth was very obvious. The dimensional increase of the mandibular variables in the patients was equivalent to, or in some cases even exceeded, that of the controls. In relation to basion, the mandibular condyles were displaced in a backward/upward direction in the patient group. Displacement in the opposite direction was recorded in the controls. It seems likely that the development seen in the patients is a reflection of a normalization of the condyle-fossa relationship made possible by enhanced condylar growth. This change should be advantageous for the function of the craniomandibular complex.

Acute Disease↗

PubMed1985

The control of condylar growth: an experimental evaluation of the role of the lateral pterygoid muscle.

The present study used 21 male albino rats to test the hypothesis that lateral pterygoid traction regulates the growth of the mandibular condyle. The condyles, the rami, and the top of each glenoid fossa were marked with metallic implants, and, following bilateral section of the condylar neck, one lateral pterygoid muscle was extirpated. On the basis of the literal details of Petrovic's cybernetic model, it was assumed that the continued forward growth of the midface and the backward translation of the glenoid fossa would combine to produce a progressive disturbance in the buccal occlusion that would, in turn, generate a reflex contraction of the remaining lateral pterygoid muscle. Initially, however, growth of the isolated condyles would have little impact on the spatial position of the rest of the mandible. As a result, the condyles on the side with the intact lateral pterygoid should grow for a time at a maximal, open-circuit rate, whereas the experimental condyle, deprived of all muscle traction, should show only a minimal "commanded" rate of growth. The serial change in the position of the condylar and ramal implants was assessed cephalometrically for 6 weeks, and between-sides differences were analyzed by randomized block analysis of variance. The presence or absence of the lateral pterygoid muscle had no significant effect on the anteroposterior position of the condylar implants and only a slight, transitory effect on their vertical position. The translation of the ramal implants, however, was greatly affected by the condylotomy. On both control and experimental sides, the mandible collapsed upward and backward until contact between the growing condyle and ramus had been achieved, whereupon a downward and forward pattern of translatory growth was re-established. Although it could not be shown that lateral pterygoid traction per se is a significant factor in the growth of isolated condyles, it was concluded that the condyle is vitally important to the translatory growth of the mandible as a whole. On the basis of these data and the current literature, a simple hypothesis was advanced for the control of condylar growth by the ongoing pattern of functional loading and for the role of this growth in the normal downward and forward displacement of the rest of the mandible.

Animals↗

PubMed1999

Arthroscopic eminoplasty for habitual dislocation of the temporomandibular joint: preliminary study.

A unique surgical technique, arthroscopic eminoplasty was undertaken in 16 joints of 11 patients with habitual dislocation of the temporomandibular joint (TMJ). There were 10 joints with subluxation and 6 joints with complete dislocation in 4 male and 7 female patients with a mean age of 33 +/- 20 years. The procedure consisted of conventional diagnostic arthroscopy, followed by shaving of approximately 3 to 5 mm in height of the articular eminence with an electric motorized shaver with bone files, depending on the bone thickness as detected by preoperative imaging. The arthroscopic eminoplasty was accomplished without any peri- or postoperative complication. During the postoperative follow-up period of 19 months on average (6-36 months), all patients were free of dislocation of the TMJ, except for one joint. The patients could open their mouth 42 +/- 6 mm without arthralgia 2 weeks after surgery, and finally 47 +/- 7 mm without any subjective symptom but small joint noises (clicking or crepitus) in 10 joints. On postoperative radiographs only minor changes of the mandibular condyle were apparent in four joints. Arthroscopic eminoplasty might become a significant procedure for habitual dislocation of the TMJ and seems to produce results comparable to open arthrotomy. Further study will be required to assess this method as an acceptable modality in the future.

Adult↗

PubMed2004

A comparative assessment of mandibular condylar position in patients with anterior disc displacement of the temporomandibular joint.

PURPOSE: The purpose of this study was to determine whether the position of the mandibular condyle in patients with anterior disc displacement (ADD) is different from that of a control group with normal joints using a novel method to quantify the irregular shape of the temporomandibular joint (TMJ). MATERIALS AND METHODS: Twenty-six magnetic resonance images of TMJs with ADD were evaluated and compared with 14 normal joints. The position of the condyle was determined by using 2 different methods: 1) measuring the horizontal and vertical normalized distances in millimeters between the geometric centers of the glenoid fossa and the condyle and 2) calculating the anteroposterior joint space ratio. RESULTS: Using the first method, the horizontal distance between the centers of the condyle and the glenoid fossa was 14.0 +/- 11.1 in the ADD group and 5.3 +/- 10.9 in the control group (P <.001). The vertical distance was 64.7 +/- 22.7 in the ADD group and 68.3 +/- 32.9 in the control group (P =.015). The ratio of the horizontal and the vertical condylar displacement in the ADD group was 2.4. Using the second method, the anteroposterior joint space ratios in the ADD group and in the control group were 1.7 +/- 0.5 and 1.2 +/- 0.4, respectively (P =.001). CONCLUSION: This study found that condyles of patients with ADD were situated more posterior and superior in the fossa than those in the control group. Moreover, in the ADD group, the posterior condylar displacement was noted to be 2.4 times greater than the superior condylar displacement.

Adolescent↗

PubMed1992

No effect of neuromuscular blockade on the temporomandibular joint position during general anesthesia.

In an attempt to determine the role that nondepolarizing neuromuscular blocking agents play in the intraoperative position of the mandibular condyle, occlusal checkbites were taken on 10 patients under general anesthesia before and after neuromuscular blockade with vecuronium. These checkbites were compared to checkbites taken preoperatively. Nondepolarizing neuromuscular blocking agents had no effect on condylar position recordings during general anesthesia. The results demonstrate that general anesthesia itself is by far the dominant factor in intraoperative condylar position changes.

Anesthesia, General↗

PubMed1990

[Condylar retrusion in the algo-dysfunctional syndrome of the mastication apparatus].

Although T.M.J. dysfunction-pain syndrome is a multicausal affection, it is obvious that occlusal disturbance is one of the greater etiologic factors. In order to evaluate the role of condylar position in the glenoid fossa, a statistical study has been made on a 16 patients series. These patients presented an uni- or bilateral T.M.J. dysfunction-pain syndrome without arthrosis, ankylosis or traumatologic deformation. The vertical and horizontal relationships of the mandibular condyle to the temporal were quantitatively evaluated from lateral tomographs. Pain and clicking were noted (Y or N) for each of the 32 T.M.J. Condylar position doesn't seem to have any relation with clicking, which is present in cases of meniscus anterior displacement. On the contrary, condylar horizontal retrusion is statistically connected with pain (p less than 0.05) even if one can see condylar retroposition without pain. On the other hand, vertical changes in condylar position cannot be connected with pain. The importance of condylar retrusion in the pain-group can surely be related to inflammatory histologic injuries at the level of the posterior disc attachment. Then, in these cases, the etiologic treatment must be focused on anterior mandibular release by orthodontics, prosthetics or orthognathic surgery.

Adolescent↗

PubMed1961

Response of condylar growth cartilage to induced stresses.

The endochondral growth apparatus of the mandibular condyles, in contrast to epiphyseal plates of long bones, reacts positively to mechanical stimulation. Roentgenographic and histologic analyses of the joint structures of two experimental rhesus monkeys, when compared with untreated controls, showed obvious morphologic and structural transformations of the condylar heads as the result of the instituted treatment. Corollary differences were found in the ontogenetic and histogenetic pattern, as well as in the hormonal control, of these condylar growth centers.

Bone and Bones↗