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Results for “Condylar position”

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At least 55 records · Page 3Linked to original sources

PubMed1999

Short-term changes of condylar position after sagittal split osteotomy for mandibular advancement.

OBJECTIVE: The goal of this study was to quantify condylar position changes after mandibular advancement surgery with rigid fixation (screws). Radiographic changes in condylar position were determined in all planes (X, Y, and Z). Computed tomography with image reconstruction was used. STUDY DESIGN: A consecutive population of patients who elected to have rigid fixation for surgical stabilization method were studied (n = 21). Computed tomography data were acquired in the axial plane through use of abutting 1.5-mm-thick slices. Data acquisition occurred 1 week preoperatively and 8 weeks postoperatively. Measurements were made from 2-dimensional reconstructions. RESULTS: The averages were as follows: lateral displacement from midline, 1.2 mm (55% of patients); medial displacement from midline, 1.5 mm (45% of patients; range, 3.2 mm); condyle angle increase from coronal plane, 3.5 degrees (60% of patients); condyle angle decrease from coronal, 4.3 degrees (40% of patients; range, 8.5 degrees); superior rotation of proximal segment, 3.2 degrees (39% of patients); inferior rotation of proximal segment, 8.6 degrees (61% of patients; range, 15.6 degrees); superior displacement, 1.2 mm (60% of patients); inferior displacement, 1.0 mm (40% of patients; range, 2.5 mm); anterior displacement, 1.6 mm (33% of patients); posterior displacement, 1.6 mm (67% of patients; range, 2.8 mm). CONCLUSIONS: Changes occurred in all planes, but the most common postoperative condyle position was more lateral; with increased angle, the coronoid process was higher and the condyle was more superior and posterior in the fossa.

Adolescent↗

PubMed2001

Maintenance of condylar position using an occlusal splint after mechanical vibrating-traction of the TMJ.

Although adequate relief of excess mechanical loading to the joint has been accepted as one of the important treatment concepts in the orthopaedic field, a treatment method for the temporomandibular joint (TMJ) to relieve excess mechanical loading has not yet been established. This study aimed to clarify the effect of an occlusal splint on the maintenance of the distracted condylar position achieved by vibrating-traction method. Vibrating dynamic traction force was applied for 5 min to the right TMJ using vibrating-traction apparatus. A flat stabilization splint was adjusted to keep the mandibular position and the condylar displacement was evaluated for 6 h after the dynamic traction procedure. Mean vertical displacement of the mandibular right first molar immediately after the vibrating-traction for the six subjects was 156 microm (ranging from 141 to 179 microm). The calculated mean condylar displacement immediately after the traction was 480 mum and could be kept to be 381 mum even after 6 h by wearing the flat stabilization splint. From the results of this study, it was revealed that the mechanically tracted condylar position could be maintained by a flat occlusal splint. It was suggested that the vibrating-traction method followed by the provision of occlusal support might have a possibility to work as a mechanical relieving procedure for the TMJ.

Adult↗

PubMed1984

Condylar position following mandibular advancement: its relationship to relapse.

Forty-one patients who elected to receive a bilateral sagittal osteotomy to advance the mandible were examined clinically and radiographically to assess condylar position preoperatively and at three specific times postoperatively. Parameters designed to measure changes in condylar and distal fragment position were located on tracings and digitized for statistical analysis. Changes in distal fragment position included advancement and clockwise rotation during the surgical interval and significant posterior relapse with continued clockwise rotation during the period of maxillomandibular fixation. A small amount of counterclockwise rotation associated with interocclusal splint removal was seen following fixation release. No significant condylar movement was seen during the surgical interval. During the period of maxillomandibular fixation, both condyles exhibited a significant superior movement, and the left condyle also moved posteriorly. No changes in condylar position were noted following release of fixation. The clinical significance of these condylar movements is not clear. Despite minimal changes, 18 patients, six of whom had had no preoperative symptoms and one of whom had exhibited reciprocal clicking, complained of temporomandibular joint pain or noise postoperatively. This suggests that maintenance of condylar position during surgery may not prevent temporomandibular joint dysfunction. In addition, the observed 37% relapse in surgical advancement in the absence of significant condylar distraction implies the interaction of other factors in the relapse process.

Adolescent↗

PubMed1999

Condylar positional changes after mandibular advancement surgery with rigid internal fixation.

The purpose of this retrospective investigation was to describe condylar positional changes in patients after mandibular advancement surgery. By superimposing on clearly identifiable cephalometric landmarks (ie, mandibular symphysis and rigid fixation screws), condylar positional changes from immediately after surgery to orthodontic appliance removal were extrapolated. Although the mandibular symphysis generally moved in either an anterior or posterior direction after surgery, condylar movements were exclusively in an upward vertical direction. Correlations were found between several measured variables, including a tendency for increased superior postsurgical movement of the condyles with increasing magnitudes of surgical advancement of the mandible. This long-term instability of skeletal relationships may be caused by a wide variety of interacting factors and events.

Adolescent↗

PubMed2002

The difference in condylar position between centric relation and centric occlusion in pretreatment Japanese orthodontic patients.

This study investigates the differences in condylar position between centric relation (CR) and centric occlusion (CO) in Japanese orthodontic patients before treatment. We employed 150 consecutive cases (age range: 6-57 years) for the study. Dental casts were mounted on a Panadent articulator with a power centric CR bite record. The differences in condylar position between CR and CO in all three spatial planes were measured using the Panadent Condyle Position Indicator (CPI). The subjects were divided into groups by age, gender, mandibular plane angle or angle classification. No significant differences in the magnitude of CPI measurements were found among the groups. The three-dimensional distances of condylar displacement on both sides were almost identical, and the superoinferior displacement (S-I) was greater (P < .0001) than the anteroposterior displacement (A-P). The S-I was greater (P = .02) on the left side than on the right side, while the A-P displacement was smaller (P < .0001) on the left side than that on the right side. Significant condylar displacement (2.0 mm for S-I and A-P, 0.5 mm for the lateral displacement, L) was found frequently in L (31.3%), S-I, and A-P, in that order. Fifty-eight (38.7%) of the subjects had significant displacement in L, S-I, or A-P. Moreover, Angle Class III subjects tended to have significant condylar displacement toward the left side. The results suggest that orthodontists should be aware of a high incidence of condylar displacement in Japanese orthodontic patients and measure condylar displacement before the start of comprehensive orthodontic treatment to unmask real jaw relationships and avoid possible misdiagnoses.

Adolescent↗

PubMed2005

Is there any difference in the condylar position and angulation after asymmetric mandibular setback?

OBJECTIVE: This study was performed to compare the condylar position and angulation on 3-dimensional (3D) views between greater setback side (GSS) and lesser setback side (LSS) after asymmetric mandibular setback (AMS) using computed tomography. STUDY DESIGN: The sample consisted of 12 Korean skeletal class III malocclusion patients with mandibular prognathism and facial asymmetry, who underwent sagittal split ramus osteotomy (SSRO) with rigid fixation. Tomographs were taken 1 month before (T1) and 6 months after surgery (T2). Position and angulation of the condyles were measured. RESULTS: At T1 stage, the condylar head in GSS showed more forward inclination on the sagittal view (P < .05) than that of LSS. Although there were significant inward and backward rotations of the condylar head in GSS (P < .01) and significant backward rotation in LSS at T2 stage (P < .05), 3D positions of the condyle in GSS and LSS were not changed after AMS. CONCLUSION: SSRO might be effective to stabilize the condylar position for AMS.

Adolescent↗

PubMed1992

Application of the condylar positioning appliance in mandibular sagittal split osteotomies with rigid skeletal fixation.

During orthodontic-surgical treatment of dentofacial deformities, centric relation of the mandibular condylar head to the fossa articularis must be maintained. Intraoperative application of the condylar positioning appliance, in combination with different surgical splints, allows three-dimensional adjustment of the jaw segments. The condylar positioning appliance can be used in osteotomies of the mandible alone, in isolated Le Fort I osteotomies, or in simultaneous osteotomies of the maxilla and mandible.

Bone Plates↗

PubMed1999

Condylar position with rigid fixation versus wire osteosynthesis of a sagittal split advancement.

PURPOSE: In this randomized clinical study, two groups of patients who underwent a bilateral sagittal split osteotomy and either wire osteosynthesis or rigid fixation were compared. PATIENTS AND METHODS: Cephalometric radiographs obtained before surgery, immediately after surgery, and at 8 weeks, 6 months, and 1 and 2 years after surgery were available for 125 of these patients, 63 with wire fixation and 62 with rigid fixation. All were traced by an independent examiner, and vertical and horizontal changes in condylar position were recorded for each period. RESULTS: Condylar movement was slightly different with the two fixation techniques beyond 8 weeks postsurgery, but the ultimate position of the condyle was not different. The condyles in both groups moved posterior and superior. There initially was a correlation between the amount of advancement and the amount the condyle moved inferior in both groups, but this diminished with time. In addition, there was a weak but significant positive relationship between forward rotation of the proximal segment and superior condylar position immediately after surgery, which did not exist at later periods. CONCLUSIONS: Whether wire osteosynthesis or rigid fixation was used, the ultimate condylar position was posterior and superior after a bilateral sagittal split osteotomy to advance the mandible. No single factor could be identified to account for this change. It is suggested that change in mechanical load may have resulted in remodeling and adaptation of the condyles.

Adolescent↗

PubMed2001

Comparison of condylar position in hyperdivergent and hypodivergent facial skeletal types.

Orthodontists have long been interested in the differences in the diagnosis and treatment of hyperdivergent and hypodivergent facial types. More recently, many orthodontists have become interested in treating to a seated condylar position or centric relation. It was the objective of this study to investigate the difference in condylar position between these 2 extreme facial types. Two groups of 33 subjects, each representing the extremes in facial type, were randomly selected and matched for age and sex. Mounted casts and the MPI instrumentation were used to measure and compare the amount of condylar distraction between the 2 groups in the horizontal and vertical planes. The total amount of change between the 2 groups was examined using a statistical t-test. There was a statistically significant greater distraction of the condyles in the hyperdivergent group in both the horizontal and vertical planes.

Adolescent↗

PubMed1982

Anatomic study of condylar position at maximum intercuspation.

An anatomic study of the mandibular condylar position was conducted on 40 dried skulls with intact dentitions. The distance between the condyle and the mandibular fossa in three different sections were measured anteriorly, superiorly, and posteriorly. The mandibular condylar was found to be in a slightly anterior position. The implications are discussed.

Cephalometry↗

PubMed2004

Impact of posterior occlusal support on the condylar position.

The purpose of this study was to investigate condylar displacement related to the loss of posterior occlusal support. Each of 23 subjects received one occlusal adjusted splint that covered all teeth from the right to the left second mandibular molar. None of the subjects had a third molar and none of them had a missing tooth or showed tooth mobility. The splint was inserted and vertical and horizontal condylar position was measured by an ultrasonic motion analyser. The splint was then unilateraly shortened tooth-by-tooth up to the canine tooth and the measurement was repeated after each shortening. Cutting off the splint's second molar on one side lead to a slight ipsilateral cranial motion of the condyle if subjects clenched with maximum voluntary force. If the second and first molar were cut off, a noticeable cranial condylar movement of about 0.3 mm was observed even when teeth occluded with low force. These results suggest that loss of posterior occlusal support as it happens in routine oral rehabilitation leads to a noticeable cranial condyle movement during registration, even if the clenching force is low.

Adult↗

PubMed1993

[Evaluation of the normal adults' condylar position in the fossa].

44 normal adults were strictly selected from 450 subjects. Fully corrected lateral tomograms and individual corrected transcranial radiograms were taken in the intercuspid position. The area and linear measurements of the joint space were performed with the aid of a computer. 70 TMJs of the fully corrected lateral tomograms were included in the present study. The measurements of joint space area showed that the normal condylar position is in the center of the fossa basically. However, obvious variations of the condylar position could be seen. Therefore, the concentric position was not the only normal physiological position of the condyle.

Adolescent↗

PubMed1994

Analysis of condylar position changes: a test of validity of posteroanterior cephalometric and 20-degree lateral cephalometric techniques enhanced by digital subtraction.

This preclinical study was designed to evaluate 20-degree lateral cephalometric and posteroanterior cephalometric techniques with digital subtraction enhancement for their ability to detect 1-, 2-, and 3-mm shifts in condylar position in two of three planes of space (horizontal or transverse and vertical). The model used was a dry human skull with a complete mandible mounted on a microscopic stage with positioning accuracy to 0.1 mm in x, y, and z planes. Analysis of variance showed no significant difference from expected values in the transverse plane (posteroanterior cephalogram only). There were significant differences in the sagittal plane (20-degree lateral cephalogram only) for the 2- and 3-mm shifts (P < .001). There were no significant differences among expected values in the vertical plane for individual increments or for increment comparisons. The magnitude of standard deviations and of the absolute value of differences indicates markedly increased variability for both techniques as compared to tomograms produced with cephalostat repositioning. The authors conclude that even with precise repositioning and digital subtraction enhancement, cephalometric radiographs are inadequate for clinical monitoring of condylar position.

Analysis of Variance↗

PubMed1995

Analysis of condylar position change on digitally subtracted Orthophos P-4 and Sectograph zonogram images.

The purpose of this study was to compare the accuracy of two single-image techniques that provide parasagittal views of the temporomandibular joint. Orthophos program 4 and Sectograph zonographic techniques were evaluated using digital subtraction to measure 1-, 2-, and 3-mm shifts of condylar position in horizontal or vertical planes. Precise repositioning of a human skull was facilitated by laser alignment beams. Statistically significant differences between radiographic techniques reflected the tendency for overestimating of shifts with program 4 and underestimation with zonographic techniques. Pooled mean difference values were 0.12 mm for program 4 images of -0.17 mm for zonograms. Program 4 images and zonograms produced with precise repositioning of anatomy approached the accuracy of tomograms and may prove useful for evaluating parasagittal alterations in condylar position in pretreatment and posttreatment radiographs.

Analysis of Variance↗

PubMed2004

Influence of the inclination of the plate of an intra-oral tracing device on the condylar position registered by tapping movement.

The object of this study was to determine the best inclination of the intra-oral tracing device to get optimum condylar position with the registration of tapping movement. Three appliances with different tracing plate inclinations were used in five healthy subjects. The tracing plates were set at 0 degrees to occlusal plane (horizontal); at the angle formed by drawing a line from condylar point to the stylus position at occlusal plane (inclined); then at the angle half to inclined (half-inclined). Subjects made Gothic arch and tapping movements (n = 30) at a 30 mm interincisal distance with the head Camper plane horizontal. The incisal and condylar points were tracked with a 6-degree-of-freedom jaw movement tracking system. The location of gothic arch apex, the distribution and mean position of 30 tapping points from intercuspal position were analyzed in incisal and condylar point between the appliances. Data were analyzed with repeated measures one-way anova. Results showed that mean position of tapping points were significantly different among the appliances. Half-inclined appliance recorded tapping points in a convergent area nearer to intercuspal position (IP) than other appliances. In all appliances, the contact points of the tapping movement were anterior to Gothic arch apex.

Adult↗

PubMed1989

The significance of condylar position using rigid fixation in orthognathic surgery.

Rigid fixation in orthognathic surgery has major advantages, particularly the elimination of postoperative intermaxillary fixation, which makes the procedure more comfortable for the patient. The main disadvantage of rigid fixation in these procedures is that errors in the position of bony segments and dislocations of the mandibular condyle during surgery may result in errors of the occlusion and cause adverse effects on the temporomandibular joint. When rigid fixation is used, the presurgical position of the condyles should be maintained. The principles of condylar positioning are described.

Fracture Fixation, Internal↗

PubMed2004

Comparison of deep bite and open bite cases: normative data for condylar positions, paths and radiographic appearances.

To compare normal overbite, deep bite and open bite cases with clinically healthy temporomandibular joints (TMJ) regarding the difference between condylar positions in centric relation (CR) and habitual or centric occlusion (CO), condylar paths and radiographic findings of condylar appearance in order to establish normative data. Three study groups of normal overbite, deep bite and open bite cases consisted each of 30 subjects with no detectable clinical signs of temporomandibular disorder. The CR-CO differences and axiographic tracings were recorded using the School Artikulator of Mack (SAM) diagnostic system. Condylar shape was evaluated on panoramic radiographs. The CR-CO differences were greater in the vertical plane in open bite cases, and direction of movements from CR to CO showed great variability. Open bite cases had significantly shorter condylar paths. Radiographic findings exhibited that 23% of the total sample showed evidence of erosion and 83% evidence of flattening of condyles. The erosion rates were higher in the open bite group, but flattening was seen more often in the deep bite group. Results of this study showed that open bite cases show larger vertical CR-CO slides and, shorter protrusion paths than normal and deep overbite cases. The radiographic appearance of condyles in non-patients may also differ significantly according to vertical incisor guidance type. Deep bite cases demonstrated a higher incidence of condylar flattening. This study indicates that the clinician should be paying special attention to the TMJ status of open bite patients.

Adolescent↗

PubMed1992

A new condylar positioning technique in orthognathic surgery. Technical note.

In two-jaw surgery, special importance must be attached to the maintenance of the condylar position, particularly in combination with rigid fixation, not only to enhance the stability of the post-operative result but also to avoid iatrogenic temporomandibular joint complications. The new positioning method reported herein is based on a mini fragmentation plate, which can be easily adapted to the bone surface. Reinforcement of the plate by autopolymerizing acrylate, injected into a silicone tube which is pushed over the plate, prevents any unnoticed deformation of the positioning device during surgery. In clinical use, this positioning method has proved to be more versatile and technically less difficult to perform than previous techniques, without any decrease in reliability.

Bone Plates↗