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Results for “Condylar position”

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At least 307 records · Page 17Linked to original sources

PubMed2002

Condylar and temporomandibular joint disc positions after mandibular osteotomy for prognathism.

PURPOSE: The purpose of this study was to compare the changes in temporomandibular joint (TMJ) morphology and clinical symptoms after sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) with and without a Le Fort I osteotomy. PATIENTS AND METHODS: Of 43 patients with a diagnosed jaw deformity, 20 underwent IVRO without internal fixation and 23 underwent SSRO with rigid internal fixation. Some operations were performed in combination with a Le Fort I osteotomy. The TMJ symptoms and joint morphology, including the disc position, were assessed preoperatively and postoperatively using magnetic resonance imaging (MRI) and axial cephalography. RESULTS: A significant difference in the direction of condylar rotation was seen in horizontal axial cephalography images (P <.01). Fewer or no TMJ symptoms were reported postoperatively by 88% of the patients who underwent IVRO with or without a Le Fort I osteotomy and by 66.7% of patients who underwent SSRO with or without a Le Fort I osteotomy. In sagittal images, no change was seen in anterior disc displacement after SSRO; however, improvement was seen in 44.4% of patients with anterior disc displacement who underwent IVRO with or without a Le Fort I osteotomy. CONCLUSION: These results suggest that SSRO does not improve anterior disc displacement; IVRO improves anterior disc displacement in the initial postsurgical period, and both procedures may improve TMJ symptoms.

Adolescent↗

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↗

PubMed1997

[Axiographic functional parameters after dysgnathia operations with special reference to the position of the temporomandibular joint].

This follow-up study was designed to identify the differences between the TMJ movements of individuals undergoing orthognathic surgery, with and without positioning of the mandibular proximal segment. A further aim was to assess the location of the terminal hinge axis before and after surgery regarding variations due to mandibular advancement or set back, respectively combined two jaw osteotomy. Mechanical axiographic tracings were documented in 14 patients undergoing orthognatic surgery without positioning of the mandibular proximal segment. The terminal hinge axis position was marked by a tattoo. After surgery two more axiographic tracings were recorded over a follow-up period of 24 months. Changes to the terminal hinge axis position were also documented. Condylar guidance angles showed no differences, whereas Bennett angles decreased by an average of 25%. Subjective or objective TMJ symptoms after surgery could be observed in 64% of the patients, compared to 50% before surgery. Considerable variations in the position of the terminal hinge axis were observed nine months after surgery, especially in the two jaw group. In Class II individuals the terminal hinge axis was found in a cranial position both after 9 and 24 months. Class III individuals with two jaw surgery also gained a long term cranial localisation, whereas Class III patients with mandibular setback only demonstrated a hinge axis position inferior and anterior compared to the preoperative reference. No statistically significant differences were apparent between the axiographic condylar movement parameters in the present group as compared to data published employing condylar positioning.

Biomechanical Phenomena↗

PubMed1999

Further displacement of condylar process fractures after closed treatment.

PURPOSE: This study examined the changes in the position of the fractured condylar process immediately before and immediately after application of arch bars and at 6 weeks after surgery in a group of patients who underwent closed treatment. PATIENTS AND METHODS: Sixty-five patients over the age of 16 years underwent closed treatment of unilateral mandibular condylar process fractures. Coronal and sagittal displacement of the condylar process was examined using Towne's and panoramic radiographs before treatment, immediately after placement of arch bars, and at 6 weeks. The change in position of the condylar process from one time to the next was analyzed statistically. RESULTS: There was a statistically significant difference (mean, -5.5 degrees) in the coronal position of the condylar processes from immediately after injury to immediately after placement of arch bars. There was great variability, with some segments becoming more medially displaced and some more laterally displaced. In contrast, mean change in the sagittal position of the condylar process was not statistically significant, although some became more anteriorly and others became more posteriorly displaced. Similarly, from immediately after placement of arch bars to 6 weeks, there was great variability in position of the condylar process, but the overall change was not statistically significant. CONCLUSIONS: The results of this study showed that position of the condylar process is not static in patients treated for condylar process fractures by closed means. These results suggest that care must be taken in basing treatment decisions on the degree of displacement or dislocation of the condylar process in presurgical radiographs.

Adolescent↗

PubMed1975

Condylotomy. A clinical and experimental appraisal of a surgical technique.

211 cases of temporomandibular joint pain/dysfunction syndrome treated by condylotomy were traced. 172 operations were investigated by questionnaire and 119 patients examined clinically and radiographically. Operated patients constituted less than 3% of all patients with the syndrome. 91% were cured or improved by surgery. The anatomical structure involved in the technique and operative complications, are discussed. Principal effects of surgery were to produce an increase in radiographic joint space and shortening of the ramus with minimal long term change in the position of the condylar head from its postoperative position. The clinical findings as regards remodelling were confirmed and investigated histologically in a primate model. The mechanisms of pain production in the temporomandibular joint pain/dysfunction syndrome are discussed.

Animals↗

PubMed2001

[Rehabilitation of patients with lower asymmetrical macrognathia].

Unilateral subcondylar vertical osteotomy of the mandibular ramus was performed in 26 patients with asymmetric mandibular prognathism (AMP). 16 of 26 patients had temporomandibular joint (TMJ) symptoms before surgery. Asymmetric mandibular prognathism was combined with maxillary micro-retrognathism in 15 patients. Condyle position was evaluated by pre- and postoperative computed tomography (CT) data. Unlike mandibular sagittal split osteotomy with rigid fixation, the vertical subcondylar osteotomy with wire osteosyntheses allows to keep preoperative condylar head position on the side of hypertrophy and thus to prevent and eliminate TMJ symptoms postoperatively. Wire osteosynthesis promotes the most complete mechanism of adaptation and self-regulation of TMJ elements in surgical treatment of patients with asymmetric mandibular prognathism. All 26 patients had no TMJ symptoms postoperatively.

Adolescent↗

PubMed2003

Kinematic analysis of a posterior cruciate retaining mobile-bearing total knee arthroplasty.

Using video fluoroscopy, 10 subjects having a mobile-bearing posterior cruciate-retaining total knee arthroplasty were analyzed to determine their in vivo kinematic patterns. Under weight-bearing conditions, while in extension, the average contact position was posterior to the mid-tibia sagittal plane with posterior translation of both condyles to 60 degrees of flexion, followed by anterior translation to 120 degrees of flexion. Under non-weight-bearing conditions, the average condylar contact positions were significantly more anterior from full extension to 90 degrees of knee flexion (P=.01). The average range of motion was 129 degrees under non-weight-bearing conditions and 119 degrees during weight-bearing. Although subjects in this study exhibited variable motion patterns, they are accommodated by the unconstrained optimized articulation of this highly conforming mobile-bearing implant.

Biomechanical Phenomena↗

PubMed2007

A comparison of MRI, radiographic and clinical findings of the position of the TMJ articular disc following open treatment of condylar neck fractures.

We examined the position and function of the articular disc after open treatment of condylar fractures by comparing magnetic resonance images (MRI) and radiographs with clinical data. MRI and radiographs were taken after treatment of 28 patients with 33 fractures of the mandibular condyles. In all cases, the disc was located in the fossa after open reduction and internal fixation (ORIF). The MRI, radiographic and clinical findings did not correlate, and damage to the temporomandibular joint (TMJ) could be seen more clearly on MRI than on clinical or radiographic examination. Damage to soft tissues seen on MRI after treatment was more pronounced in dislocated than in displaced fractures.

Adult↗

PubMed2001

The effect of surgeon experience on component positioning in 673 Press Fit Condylar posterior cruciate-sacrificing total knee arthroplasties.

Component angles of 673 Press Fit Condylar (PFC) total knee arthroplasties were measured from standard short-leg radiographs. The femoral and tibial resections were performed with intramedullary and extramedullary instrumentation. The mean coronal tibial component angle was 88.59 degrees (SD, 2.28 degrees; range, 78-98 degrees ), with 17.1% having values <87 degrees and 1.9% having values >93 degrees. The mean coronal femoral component angle was 97.43 degrees (SD, 3.44 degrees; range, 84-115 degrees ), with 9.1% having values <94 degrees and 13.1% having values >100 degrees. An ideal tibiofemoral angle of 4 degrees to 10 degrees of valgus was achieved in 75.3% of patients, being <4 degrees in 18.6% and >10 degrees in 6.1%. Alignment was not significantly different between consultant and trainee surgeons. Although varus positioning of the tibial component was the commonest error, the wide range of femoral component angles signifies problems with standard intramedullary femoral guides.

Arthroplasty, Replacement, Knee↗

PubMed1985

Cephalometric analysis of condylar adaptations to altered mandibular position in adult rhesus monkeys, Macaca mulatta.

Morphological adaptation to altered position of the mandible was investigated in 19 young adult rhesus monkeys (n = 10 experiment and 9 control). The experimental animals had a bite-splint cemented to the maxillary dentition which opened the bite interincisally by 15 mm and was worn continuously for 48 weeks. Lateral radiographic cephalograms were taken prior to the experiment and at 12-week intervals thereafter. Computerized cephalometry, facilitated by the use of radio-opaque bone markers, was used to assess changes in mandibular position and morphology. An immediate effect of the bite-splint was the clockwise rotation (opening) of the mandible and anterior translation of the condyle on the articular eminence, much as occurs normally during jaw depression. During the next 48 weeks, the mandible (1) rotated anti-clockwise (closed) due mainly to antero-superior displacement of the maxilla and intrusion of the mandibular dentition and (2) underwent a significant increase in length (p less than 0.05). These findings indicate that the mandibular condyle of young adult monkeys is capable of small, but biologically significant, compensatory growth after displacement.

Adaptation, Physiological↗

PubMed1995

New definition for relating occlusion to varying conditions of the temporomandibular joint.

Centric relation is the accepted term for defining the condylar axis position of intact, completely seated, properly aligned condyle-disk assemblies. However, some structurally deformed temporomandibular joints may function comfortably, even though they do not fulfill the requirements for centric relation. A wide range of temporomandibular disorders from partial to complete disk derangements with or without reduction may adapt to a conformation that permits the joints to comfortably accept maximal compressive loading by the elevator muscles. There has been no accepted terminology to define the condition or position of such joints. The purpose of this article is to define a new term, adapted centric posture, and to explain its rationale and how it is determined. Verification of successful adaptation is an important step in diagnosis, because it rules out structural intracapsular disorders as a source of orofacial pain and establishes responsible guidelines for initiation of occlusal treatment or prosthetic dentistry. It also establishes a much needed terminology for more specific description of temporomandibular joint position and condition for clinical research on the relationship between occlusion and the temporomandibular joints.

Adaptation, Physiological↗

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↗

PubMed2005

Expression of Notch1 and Math1 in mandibular condyle cartilage in neonatal mice.

On the basis of the cellular morphological changes in the cartilaginous area, the mandibular condylar cartilage is histopathologically composed of four different cell layers--fibrous, proliferative, maturative, and hypertrophic. Reaction for Notch1 was present in the hypertrophic cells only. However, Math1 was locally distributed in the hypertrophic layer and partially in the proliferative layer. The expression patterns of Notch1 and Math1 were slightly different. These results suggest that the morphogenesis regulation factors of Notch1 and Math1 may play some role in mandibular condylar cartilage. Positive reactions to osteopontin, as a control, were detected in the cytoplasm of all layers, although they varied from published data.

Animals↗

PubMed1999

Treatment of TMJ static disk with arthroscopic lysis and lavage: a comparison between MRI arthroscopic findings and clinical results.

Arthroscopic surgery using the lysis and lavage technique was performed on 30 temporomandibular joints (TMJs) of 26 patients with the clinical and radiological (pseudodynamic Magnetic Resonance Imaging) diagnosis of static disk (SD). Parameters of condylar movement, position of the disk in relation to the condyle in open and closed mouth positions and mobility of the articular disk were evaluated both clinically and radiologically using pseudodynamic Magnetic Resonance Imaging (MRI) before and after surgery. Subjective parameters of pain and functional limitation were also evaluated clinically. The results showed that all the clinical and radiological parameters analyzed improved significantly in all the patients included in the study. In view of the results, the authors concluded that SD should be added to the existing categories of TMJ internal derangements. Pseudodynamic MRI is the diagnostic technique of choice in these cases and arthroscopic surgery with lysis and lavage followed by active physical therapy is an effective treatment modality in this type of pathology.

Adult↗

PubMed1990

[A study of active induction of orthodontic therapy in TMJ dysfunction syndrome--from the data of patients with TMJ dysfunction in adolescents].

It seems that active orthodontic therapy using multi-bracket appliances presents effective assurance of a physiological stable occlusion for TMJ dysfunction syndrome in adolescents. The efficiency and problems concerning the progress of active orthodontic therapy after splint therapy were examined from the data of the change of occlusal conditions, and the function of masticatory muscles before and after therapy for TMJ dysfunction from four cases for which we performed orthodontic therapy activity. 1. All of the occurring symptoms of the TMJ dysfunction syndrome (limitation, pain, sound) in the progress of orthodontic therapy were concerned with using intermaxillary elastic. The symptom which occurred in process of using only intra-maxillary elastic was just a malaise of the TMJ. Also the sound of the TMJ relapsed in the process of using class III intermaxillary elastic and recurred after the multi-bracket appliance was removed. In this case, the condylar vertical position after orthodontic therapy changed from the lower position to the center position compared with the first visit. 2. Malocclusion was improved with orthodontic therapy in all four patients. 3. The function of the masticatory muscles after orthodontic therapy was improved in comparison with the first visit by evaluation of the masticatory muscles activity and the state of silent period.

Adolescent↗

PubMed1990

[Research of condylar movement on nonworking side during quantitative lateral movement of mandible].

Cephalometric laminagraphs were taken on 40 left and right sides of 20 adults with normal occlusion. It was found that condyle of nonworking side during quantitative lateral movement at incisal region with 1mm interval up to 3mm. The results were analyzed by computer superposition graph. The results were as follows: 1. The displacement of condyle during quantitative lateral movement of the mandible was 1.00mm, 1.93mm and 2.88mm at condylar top from intercuspal position to a maximum 3mm, 1mm by 1mm average, respectively. The displacement at condylar center was 0.97mm, 1.92mm and 2.85mm average, respectively. It was noticed that condyle on nonworking side with lateral movement translated equal distances. 2. The inclination of condyle by the quantitative lateral movement of the mandible was 45.41 degrees, 49.13 degrees and 48.59 degrees at condylar top from intercuspal position to a maximum 3mm, 1mm by 1mm average, respectively. The inclination at condylar center was 44.21 degrees, 48.06 degrees and 48.44 degrees average, respectively. Directional stabilizing with condylar movement, was seen. 3. The range of condylar movement from intercuspal position, at condylar center was maximum; 40.1 degrees, minimum; 0.0 degrees, average; 10.05 degrees, SD; 7.98 degrees. 4. The results of the survey on rotation factor with condylar movement revealed that there was a slight difference, and the movement of condyle was like bodily shift.

Adult↗

PubMed1995

Comparative studies on check-bite and central-bearing-point method for the remounting of complete dentures.

Thirty-six complete dentures were remounted both with check-bite as well as central-bearing-point (CBP) registration. The mandibular or denture position was registered in the condylar area three times with each method. Two independent operators carried out the registrations. One half of patients had their occlusion equilibrated according to the check-bite registration, the other half in the central-bearing-point position. After individual determination of the hinge axis the upper dentures were mounted by a face-bow transfer into a Dentatus articulator. A total of six registrations was performed and repeatedly compared in the condylar area in three dimensions using a computer supported measuring device. The reproducibility of the check-bite registration was 0.37 +/- 0.33 mm, with a maximum of 1.77 mm. For the central-bearing-point method this was 0.29 +/- 0.26 mm with a maximum of 1.56 mm. The mean difference in condylar position between both methods was 0.66 +/- 0.55 mm with a maximum of 4.02 mm. A third independent operator re-examined 30 of the patients 2-3 weeks after the remounting and evaluated the adaptation to the new dentures. Those patients whose dentures were equilibrated with the central-bearing-point method tended to cope better with their dentures and suffered on average from fewer pressure spots.

Adaptation, Physiological↗

PubMed2000

Condylar repositioning in mandibular retrusion.

STATEMENT OF PROBLEM: There has been debate about which anteroposterior maxillomandibular relationship should be used in fixed and removable prosthodontics for patients without a definite maximal intercuspation. The choice has important implications for complete denture fabrication in which any guidance to the previous dentulous maximal intercuspal position is missing. PURPOSE: This study was designed to estimate the posterior displacement that takes place at the mandibular condyles and occlusal surfaces when the mandible is moved from maximal intercuspal position to the most retruded mandibular position. MATERIAL AND METHODS: Articulated occlusal models of 18 subjects with a natural dentition and well-defined maximal intercuspation were studied. Models were rearticulated in retruded contact position, and the original vertical dimension of occlusion was restored by eliminating all interfering occlusal contacts on the retruded path of closure. Measurement of change in condylar position was estimated using a SAM2 articulator with condylar position indicator. Posterior displacement at the occlusal surfaces was measured with a traveling microscope. RESULTS: Condylar analog retrusion in the horizontal plane at the initial retruded contact position varied from 0.6 to 2.4 mm (mean 1.0 +/- 0.4 mm); however, after occlusal adjustment to restore the original vertical dimension of occlusion, retrusion was reduced to a range of 0 to 0.4 mm (mean 0.2 +/- 0.1 mm). Retrusion at the occlusal surfaces was found to vary from 0.4 to 1.5 mm (mean 0.7 +/- 0.3 mm) at retruded contact position; however, after occlusal adjustment, retrusion was reduced to a range of 0 to 0.5 mm (mean 0.2 +/- 0.1 mm). CONCLUSION: Posterior displacement at both the occlusal surfaces and the condyles was small when interfering occlusal contacts on the retruded path of closure were removed.

Adult↗