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Results for “Condylar position”

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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↗

PubMedDate not supplied

A mandibular propulsive appliance modulates collagen-binding integrins distribution in the young rat condylar cartilage.

We have previously shown that a mandibular propulsive appliance (MPA) stimulates cell proliferation and the synthesis of growth factors in the rat condylar cartilage. The aim of this study was to evaluate the effects of a MPA in the distribution of the integrin subunits alpha1 and alpha2 in this cartilage. Twenty eight days-old male Wistar rats were divided into treated (T) and age-matched control groups (C). Treated rats wore the appliance during 3, 5, 7, 9, 11, 15, 20, 30 and 35 days. The condyles were fixed, decalcified and paraffin-embedded. The distribution of alpha1 and alpha2 was studied by immunohistochemistry. Alpha1 distribution was uniform along the cartilage, increasing in 48 days-old rats (C20). Treated animals anticipated this increase to the age of 36 days (T9). The number of alpha2-positive cells was increased in C9 in the anterior condylar region, in C9 and C20 in the middle region and showed no differences in the posterior region. The MPA apparently abolished all variations, leading to a single increase at T30 in all regions. These results suggest that integrins containing the alpha1 and alpha2 subunits are modulated by forces promoted by the MPA, participating of the biological response to this therapy.

Animals↗

PubMed1996

[Position of the disc in collum mandibulae fractures--a magnetic resonance tomography study].

39 condylar mandibular fractures were examined by magnetic resonance imaging (MRI) within the first 12 hours after trauma prior to therapy. A new classification has been applied on the traumatic disc displacements. Three types A, B, C can be distinguished. Type A means no displacement in relation to the condylar fragment and the fossa. Type B means a displacement in the transversal plane exceeding the physiologic range of movement. Type C means displacement in the sagittal as well as in the transversal plane which exceeds the physiologic range of movement of the disc. The classified type of displacement could not be correlated exactly with dislocation and position of the bony fragments. Therefore the type of displacement cannot be predicted from conventional radiographs. Three cases of evident rupture of the disc in the biconcave zone could be shown by MRI. This kind of displacement has not been represented in the classification yet. In a presented case a rupture of the disc had been depicted preoperatively and the disc could be repaired via an preauricular approach. By means of MRI surgeons in future are able to pay more attention to the traumatology and reconstructive surgery of the temporomandibular disc.

Fracture Healing↗

PubMed1998

The distribution of the auriculotemporal nerve around the temporomandibular joint.

OBJECTIVE: The purpose of this cadaver dissection was to study the position of the auriculotemporal nerve in relation to the mandibular condyle, capsular tissues, articular fossa, and lateral pterygoid muscle and to evaluate the anatomic possibility of nerve impingement or irritation by the surrounding structures. STUDY DESIGN: Eight cadaveric heads (16 sides) were dissected. The auriculotemporal nerve was identified by following its course around the middle meningeal artery. The course of the nerve trunk was dissected from the middle meningeal artery to the terminal branches within the temporomandibular disk. The horizontal distance between the auriculotemporal nerve and the medial portion of the condyle/condylar neck was measured. The vertical distance from the most superior portion of the articular condyle to the superior border of the auriculotemporal nerve was measured. RESULTS: The auriculotemporal nerve was identified on each side, and a single trunk was evident along the medial aspect of the condylar neck. At the posterior border of the lateral pterygoid muscle, the nerve trunk was in direct contact with the condylar neck in every specimen. The average vertical distance between the superior condyle and the nerve was 7.06 mm (+/- 3.21 mm); the range was 0 to 13 mm. The vertical distance between the nerve and the superior condyle on one side of the specimen did not correlate with the distance on the contralateral side. CONCLUSION: The auriculotemporal nerve trunk has a close anatomic relationship with the condyle and the temporomandibular joint capsular region, and there is evidence of a possible mechanism for sensory disturbances in the temporomandibular joint region. In all cases, the nerve was in direct contact with the medial aspect of the capsule or condylar neck. Because there is no correlation between the positions of the nerves on the right and left sides, only one side may be affected. The nerve was also observed to course in direct apposition to the lateral pterygoid muscle. The findings support the hypothesis that the anatomic and clinical relationship of the auriculotemporal nerve to the condyle, articular fossa, and lateral pterygoid muscle may be causally related to compression or irritation of the nerve, producing numbness or pain, or both, in the temporomandibular joint region.

Adult↗

PubMed1991

[Hinge endoprosthesis of the knee joint. Long-term results based on the Blauth prosthesis].

Knee prostheses of the condylar or hinge type have constructional features that have both advantages and disadvantages. Both types are compromises as a result of different demands. Here we report long-term results with the Blauth prosthesis as an example of the efficiency of the hinge concept. The Blauth prosthesis is constructed according to the low-friction principle without a weight-bearing axis. Load transmission to the bone is accomplished by large interface areas. The sliding bearing of the patella is oriented perpendicular to the transverse axis of rotation. A prospective multicentric study reports on 511 prosthesis with a follow-up between 1 and 15 years. Aseptic loosenings were confirmed in 1.2% of the patients, deep infections in 3.3%. The survival analysis showed a probability of 89% that a prosthesis would not have a deep infection or loosen. A hinged knee prosthesis shows positive long-term results even compared with the condylar types if the relevant principles of construction are adequately considered.

Aged↗

PubMed2002

Correlation between facial morphology, mouth opening ability, and condylar movement during opening-closing jaw movements in female adults with normal occlusion.

The aim of this study was to investigate the relationship between parameters of facial morphology, maximal voluntary mouth opening ability, and condylar movements in 21 adult females, aged between 20 and 24 years. The subjects had a normal occlusion without sign or symptoms of temporomandibular joint (TMJ) dysfunction. Mandibular movements were recorded using an opto-electric jaw movement recording system with six degrees of freedom under a series of maximal mouth opening-closing movements. Maximal jaw opening and coincident condylar movement were measured three-dimensionally. The mean values of the incisor and condylar path were 41.1 +/- 3.5 mm (range 35.6-50.9 mm) and 12.8 +/- 2.8 mm (range 8.1-19.2 mm), respectively. Although the positive correlation between maximal jaw opening and facial morphology was significant, none of the variables significantly differed between the value of the condylar path and facial morphology. The length of the path of maximum incisor movement and the condylar path during mandibular movement also did not correlate. Stepwise multiple regression analysis indicated a positive association between the maximal length of the incisor path and the cephalometric value of mandibular ramus inclination (R2 value was 0.369). The results of this study suggest that facial morphology size has a limited effect on maximal voluntary mandibular opening and condylar movements in normal adult female subjects.

Adult↗

PubMed1995

A new method for three-dimensional reconstruction and animation of the temporomandibular joint.

The aim of this project was to develop a new method for the three-dimensional reconstruction and animation of the temporomandibular joint (TMJ). Magnetic resonance (MR) tomograms of the TMJ were combined, using an extraorally placed reference system, with jaw motion data, recorded with six degrees of freedom, by means of the opto-electronic tracking system Jaws-3D. The three-dimensional reconstruction of the TMJ was calculated and animated on a graphics workstation by means of kinematic transformations. A subject without any past or present history of myoarthropathies of the masticatory system, performed jaw opening and closing and chewed chewing gum. The animation provided a three-dimensional visualisation of the movements of the entire condyle within the fossa. The condyle-fossa distance was computed for every condylar point and represented by shading the surface of the condyle with pseudo-colours. The position of the minimum distance between condyle and fossa was calculated and displayed in a plane graph representing the condylar surface.

Humans↗

PubMed2001

[Immortalization of the rabbit mandibular condylar chondrocyte with SV40].

OBJECTIVE: To establish an immortalized cell line of the mandibular condylar chondrocyte (MCC). METHODS: Reconstructed retroviral vector pLN/SV40 containing the large T antigen and neomycin-resistance genes were transfected into the packaging cells PA317 using lipofectin transfection method. Then the primarily cultured cells derived from mandibular condylar chondrocytes(MCCs) of New Zealand rabbits were infected with the positive retrovirus medium and monoclone was selected with G418. Specific primer of large T antigen was designed and PCR was used to detect the integrating of large T antigen gene. The positive cell clones were subcultured and their growth characteristics were compared with untransfected cells. RESULTS: 10 cell clones of the transduced cells showed the positive gene fragment of 1,196 bp, and 5 of them had been further subcultured for more than 30 passages. One clone of A21 had been passaged for more than 100 times in nearly one and half year, and named immortalized mandibular condylar chondrocyte (IMCC). IMCCs were polygonal-shaped, similar to MCCs; the population doubling time of IMCC and MCC were 30.86 h and 78.95 h respectively. Subculture, freezing and recovering had no effect on cellular shape and proliferation of IMCC. CONCLUSIONS: An immortalized cell cline derived from the rabbit MCC has been successfully established.

Animals↗

PubMed2006

Orthodontic treatment changes of chin position in Class II Division 1 patients.

INTRODUCTION: Because most patients with skeletal Class II malocclusions also have mandibular deficiencies, treatment plans should include improvement in chin projection. On that basis, the purposes of this study were to (1) determine how Class II treatment affects anteroposterior (AP) chin position in growing subjects and (2) ascertain the most important determinants of AP chin position. METHODS: Pretreatment and posttreatment lateral cephalograms of 67 treated patients (25 extraction headgear and Class II elastics, 23 nonextraction headgear, and 19 Herbst) were collected, traced, and digitized. The average pretreatment age was 12.2 years (range, 9-14 years), and the average treatment duration was 30.2 months (range, 17-65 months). Cephalometric changes were compared with 29 matched untreated Class II controls. Mandibular superimpositions were used to evaluate condylar growth and true mandibular rotation. RESULTS: All 3 treatment methods produced normal dental relationships and restricted or inhibited AP maxillary growth, with no significant improvement of AP chin position. Differences between changes in vertical position of the maxilla, maxillary and mandibular molars, and condylar growth could not reliably predict changes in chin position. Analyses demonstrated that true mandibular rotation was the primary determinant of AP chin position. Stepwise multiple regression showed that, combined with true mandibular rotation, condylar growth and movements of the glenoid fossa accounted for 81% of the variation in AP changes of pogonion. CONCLUSIONS: Contemporary treatments do not adequately address mandibular deficiencies. Future treatments must incorporate true mandibular rotation into Class II skeletal correction.

Adolescent↗

PubMed2005

Mandibular setback by sagittal split ramus osteotomy: a 12-year follow-up.

Short- and long-term skeletal changes after mandibular setback were analyzed using bilateral sagittal split ramus osteotomy. Twelve patients who had undergone mandibular setback surgery between 1986 and 1990 were available for long-term cephalography on average 12 years after primary surgery. The mean amount of surgical setback had been 6.4 mm. After the first postoperative year, there was skeletal relapse of 1 mm at the B-point and pogonion (Pg), amounting to 14% of the initial skeletal setback. In contrast to condylar displacement and proximal segment rotation, osteotomy slippage was associated with positional changes at the B-point and Pg. From 1 to 12 years postoperatively, the B-point and Pg remained stable. Mandibular ramus and corpus length decreased 2.1 mm and 1.3 mm, respectively, indicating remodeling at the osteotomy sites and probably condylar resorption.

Adolescent↗

PubMed2005

Changes in the chewing path of patients in skeletal class III with and without asymmetry before and after orthognathic surgery.

PURPOSE: The purpose of this study was to examine the relation between changes in the condylar long axis and the chewing path before and after mandibular ramus osteotomy for patients with prognathism with and without asymmetry. PATIENTS AND METHODS: Eleven men and 16 women with mandibular prognathism were divided into groups on the basis of symmetry and osteotomy procedure. Preoperative and postoperative frontal chewing paths were recorded. The chewing path consisted of 4 components: deviated side range, undeviated side range, vertical range, and incisal path angle. The angle of the condylar long axis and the 4 components of the chewing path were compared between groups and the differences were analyzed statistically. RESULTS: No significant differences in each of the 4 chewing path components were found between groups on the basis of symmetry or osteotomy procedure. A positive correlation was found between the changes in incisal path angle when chewing on the undeviated side and condylar long axis angle on the undeviated side (P < .05). A positive correlation was also found between the changes in undeviated side range when chewing on the deviated side and condylar long axis angle on the deviated side (P < .05). CONCLUSION: This study suggests that surgically induced increase in the condylar long axis is correlated with increase in side range and incisor path angle, although surgical orthodontic treatment does not significantly change the chewing pattern.

Adult↗

PubMed1985

Dentofacial orthopedics in relation to somatic maturation. An analysis of 70 consecutive cases treated with the Herbst appliance.

Mandibular treatment changes were related to somatic maturation in 70 consecutive cases of Class II malocclusion (52 boys and 18 girls, aged 10 to 16 years) treated with the Herbst appliance for an average period of 7 months. Sagittal and vertical alterations in mandibular condylar growth and sagittal changes in molar and incisor tooth position were analyzed by means of mouth-open profile roentgenograms. The somatic maturity level of the patients was assessed by means of longitudinal growth records of standing height. The treatment period was related to the peak height velocity by dividing the patients into three growth-period groups: prepeak, peak, and postpeak. Herbst treatment resulted in Class I dental arch relationships in all patients. Post-Herbst treatment changes were not evaluated in this study. Sagittal condylar growth was increased and the mandibular molars and incisors were moved anteriorly. When the mandibular skeletal and dental changes were related to the subjects' somatic maturation, significant differences between the different growth periods existed in boys and tendencies were noted in girls as follows: sagittal condylar growth was most pronounced in the peak period, anterior molar movement was equally large in all growth periods, and anterior incisor movement was most extensive in the postpeak period. To take advantage of the increase in condylar growth response and to reduce the time of posttreatment retention, it is suggested that Herbst therapy be instituted close to peak height velocity.

Activator Appliances↗

PubMed2006

Expression of type X collagen and capillary endothelium in condylar cartilage during osteogenic transition--a comparison between adaptive remodelling and natural growth.

Adaptive remodelling of the condylar cartilage in response to mandibular protrusion constitutes the rationale for bite-jumping appliances to solicit growth modification. By investigating the expression of type X collagen and capillary endothelium, this study was designed to evaluate the osteogenic transition of chondrogenesis during adaptive remodelling of condylar cartilage and compare it with that under natural condylar growth. One hundred female Sprague-Dawley rats, 35 days of age, were divided into five experimental groups (n = 15, fitted with bite-jumping appliances) where condylar adaptation was created by forward repositioning of the mandible, and five control groups (n = 5) where the condyles underwent natural growth. The animals were sacrificed at 3, 7, 14, 21 and 30 days and 7 mum serial sections of the condyles were processed for in situ hybridization and immunohistochemical analyses. The expression of type X collagen in the hypertrophic zone and capillary endothelium in the erosive zone of condylar cartilage were examined to evaluate osteogenic transition, a critical programme leading to endochondral ossification. The results showed that (1) The temporal pattern of the expression of type X collagen and capillary endothelium during condylar adaptation coincided with that during natural condylar growth. (2) The amount of the expression of these two factors during condylar adaptation was significantly higher than that during natural growth (P < 0.001). It is suggested that condylar adaptation in growing rats triggered by mandibular forward positioning enhances osteogenic transition which eventually results in increased bone formation.

Animals↗

PubMed2006

The comprehensive evaluation of temporomandibular disorders seen in rheumatoid arthritis.

BACKGROUND: We studied clinical signs and symptoms of temporomandibular disorders and radiological changes in the temporomandibular joint from patients with rheumatoid arthritis (RA) compared to patients with myofascial pain dysfunction of the temporomandibular system and control patients to evaluate clinical and radiological relationships. METHODS: A cross-sectional, controlled, clinical and radiological study was planned and 99 subjects (69 patients and 30 controls) were included in the study. RESULTS: Twenty-three patients with RA (69.7 per cent) had painful temporomandibular joint. Fifty-five per cent had myofascial pain dysfunction according to the research diagnostic criteria for temporomandibular disorders (TMD). Nearly all of our patients with RA (93.9 per cent) had symptoms, and almost all of them had positive findings of TMD in high resolution computed tomography. Condylar head resorption, joint space narrowing and degeneration were statistically more prominent features in patients with rheumatoid arthritis compared with controls (p < 0.05). The pain score on active palpation correlated with the number of the mandibular subchondral cysts on high resolution computed tomography (r = 0.6, p < 0.05). CONCLUSION: Although the myofascial pain of the temporomandibular system is an important cause of pain in rheumatoid arthritis, prospective controlled studies are needed to develop effective therapeutic strategies for these patients.

Adolescent↗

PubMed1990

[Proposal for a dynamic study of the temporo-mandibular joint, using a computerized image analyzer].

With the aim to go deep into the knowledge of the morpho-functional anatomical characteristics of the temporo-mandibular joint in humans, a dynamic method of study by means of a computerized analyzer of images is suggested. The acquired advantages are the following: a) the accuracy of evaluation of the chosen morphometric parameters; b) the working speed, from which results: c) the possibility to increase adequately the number of cases and d) the possibility to easily investigate many parameters with a very high accuracy of the quantitative results. Both right and left temporo-mandibular joints of adult individuals aged from 18 to 53 have been studied utilizing lateral tomographies focused at 3.3 mm to the lateral surface of the condylar head. The evaluations were done both in the position of completely closed mouth and in extreme opening. From the barycentre of the condyle several straight lines were drawn according to the figure 2. The length of the segment a-b (distance of profiles of the condyle and mandibular fossa) were evaluated in all the lines counter-clockwise and the results submitted to a statistical analysis. The results furnish very good information on the normal or pathological anatomical characteristics, of the joint.

Adult↗

PubMed1992

Aberrant mandibular growth: theoretical implications.

There is a multiplicity and variety of studies investigating mandibular growth. The exact role of the mandibular condyle in influencing mandibular growth is still a point of conflict. This study was conducted with six subjects who had different condylar defects. The cranium and the skeletal profile, as well as the position of the maxilla and the mandible, were investigated. In all cases, the mandible showed a tendency toward posterior rotation. The total mandibular length was reduced with deficient corpus length and ramus height. The influence of the integrity of the condylar head and its normal articulation in the temporal fossa on mandibular growth were emphasized.

Adult↗

PubMed1990

A radiographic and histologic study of the topographic relations in the temporomandibular joint region: implications for a nerve entrapment mechanism.

A radiographic and histologic investigation was performed in 18 temporomandibular joint (TMJ) autopsy specimens. Disc position was determined arthrotomographically. The pathway of the nerve branches in the vicinity of the joint was reconstructed from serial sagittal or frontal histologic sections. The relationship between the joint components and the different nerves running in the vicinity of the joint was studied. The results revealed the existence of topographical prerequisites for mechanical influence upon the nerve branches passing in the TMJ region. In two joints, both with a displaced disc, the auriculotemporal nerve trunk was almost in contact with the medial aspect of the condyle instead of having its normal sheltered course at the level of the condylar neck, thus exposing the nerve to the risk of mechanical irritation during condylar movements in an anteromedial direction. Two joints with normal disc position had an extension of the medial fossa wall in a caudal direction. In these joints the auriculotemporal nerve had its course between the condyle and the elongated fossa wall, exposing it to the risk of mechanical irritation during medial disc displacement. Compression of the masseteric nerve anterior to the TMJ was found in one joint with excessive condylar translation. The deep posterior temporal nerves may pass close to the anterior insertion of the joint capsule on the temporal bone, exposing them to the risk of mechanical irritation when there is condylar hypermobility. It was also found that the inferior alveolar and the lingual nerves may pass close to the medial part of the condyle. In joints with this nerve topography, a medially displaced disc could interfere mechanically with these nerves. These findings could offer an explanation for the sharp, shooting pain felt locally in the joint with jaw movements and the pain and other sensations projecting to the terminal area of distribution of the nerve branches in the vicinity of the TMJ such as the ear, temple, cheek, tongue, and teeth.

Aged↗

PubMed1996

Influence of choice of reference point on the condylar movement paths during mandibular movements.

Series of four open-close, protrusive and lateral movements were recorded by the six degrees of freedom jaw movement recording system OKAS-3D in 20 healthy subjects. Consequently the movement paths of nine condylar points, the palpated lateral pole and eight points located on a square parallel to the sagittal plane with an edge of 10 mm and centred around the lateral pole were calculated. For all movements except the protrusive movements, the 3-D excursions of the condylar points strongly depended upon the choice of condylar reference point (ANOVA, P < 0.001). During laterotrusive movements the Bennett angle and the Bennett shift also varied significantly according to the position of the reference point (ANOVA, P < 0.001). The results of this study underline that comparison of condylar movements between different studies is only possible when the same condylar reference point is used. General consensus on the choice of condylar reference point is thus needed.

Adolescent↗