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PubMed1980

[Growth hormone: mode of action on different varieties of cartilage (author's transl)].

1) The growth of epiphyseal cartilages of long bones, of spheno-occipital synchondrosis of the cranial base, of the cartilage of the nasal septum, of lateral cartilaginous masses of the ethmoid, of cartilage between body and greater wings of the sphenoid (all stemming from the primary cartilaginous skeleton of the organism), is subject to general extrinsic factors and, more specifically, to the growth hormone (STH) and somatomedin. In this case, orthopedic devices can alterate the direction but not the amount of growth. 2) The growth of condylar, coronoid and angular cartilages of the mandible, of the cartilage of the midpalatal suture, and of the cartilage in some cranial sutures (all of secondary formation during phylogenesis and ontogenesis) is subject to local extrinsic factors as well as to growth hormone and somatomedin. In this case, appropriate orthopedic devices may modulate both the direction and the amount of growth. 3) Our cybernetic models attempt to account for the mechanisms of facial growth. By intensifying the forward growth of the nasal septum cartilage, the STH and somatomedin stimulate the forward growth of the upper jaw, i.e. the forward positioning of the superior dental arch (the position of which is the "constantly changing reference input" of the servosystem). The "operation of confrontation" between the position of the upper and lower occlusal surfaces (the position of the lower dental arch is the "controlled variable" of the servosystem) gives then rise to a "deviation signal" (originating from detectors of occlusal adjustment) whose "reduction" is made possible by a supplementary postural activity of the lateral pterygoid muscle resulting, extemporaneously, in an appropriate forward positioning of the mandible and, with time, in a supplementary growth of the condylar cartilage. By intensifying the outward growth of lateral cartilaginous masses of the ethmoid and of the cartilage between the body and greater wings of the sphenoid, the STH and somatomedin bring about a lateralization of both the left and right sides of the upper jaw and, in this way, stimulate the growth of the secondary cartilage of the midpalatal suture.

Animals↗

PubMed1995

Mandibular skeletal changes induced by early functional treatment of Class III malocclusion: a superimposition study.

A superimposition study on mandibular stable structures was performed to evaluate changes in mandibular rotation and in the direction of condylar growth induced by early treatment of Class III malocclusion by a functional appliance (removable mandibular retractor). A sample of 18 children with treated Class III malocclusions, mean age at the first observation (immediately before the beginning of treatment) 5.47 +/- 1.14 years, mean age at the second observation 8 +/- 1.29 years, mean observation period 2.5 +/- 0.9 years, was compared with a control group of 18 children with untreated Class III malocclusions, mean age at the first observation 5.72 +/- 1.11 years, mean age at the second observation 7.86 +/- 1.44 years, mean observation period 2.27 +/- 0.92 years. No statistically significant difference between the two groups was recorded for positional (total) rotation of the mandible. A significant upward-forward direction of condylar growth was assessed in the treated group (p < 0.001). This therapeutically induced change in growth direction of the mandibular condyle was considered a skeletal sign of anterior morphogenetic rotation of the mandible, i.e., a mechanism compensating for excessive mandibular growth.

Adaptation, Physiological↗

PubMed2002

Three-dimensional evaluation of positional change of the condyle after mandibular setback by means of bilateral sagittal split ramus osteotomy.

OBJECTIVE: The aim of this study was to evaluate condylar displacement in 3 dimensions by means of computed tomography after mandibular setback by sagittal split ramus osteotomy with rigid fixation and to compare these results with those from patients with mandibular advancement. STUDY DESIGN: Thirty Korean subjects with skeletal class III malocclusion who had undergone mandibular setback by sagittal split ramus osteotomy had computed tomographs taken. Tomographs were taken to evaluate the temporomandibular joint 1 month before and approximately 1 month after surgery. The position and angulation of the condyle were measured on axial or sagittal views. These measurements were analyzed to determine any correlations between the amount of mandibular movement and condylar displacement. RESULTS: The results of this study show that the condyle tends to move inferiorly and rotate inward on the axial view and backward on the sagittal view by a statistically significant amount. CONCLUSION: The positional change of the condyle after sagittal split ramus osteotomy was not correlated with the amount of the setback.

Adolescent↗

PubMed2003

Lateral functional shift of the mandible: Part I. Effects on condylar cartilage thickness and proliferation.

Lateral functional shift of the mandible is characterized by transverse rotation of the entire mandible about a vertical axis toward 1 side of the head. The effect of this shift is that the condyle on the side opposite the direction of the shift is displaced anteriorly, or protruded, while the condyle on the side toward the shift is more stable positionally and is likely to be slightly retruded. According to the view that growth of the mandibular condylar cartilage (MCC) adapts to its local functional-biomechanical environment, differential changes in metabolic activity of the MCC would be expected on the nonprotruded and the protruded sides. To evaluate this hypothesis, 21 rats (28 days old) were fitted with intraoral positioners designed to shift the mandibular postural position asymmetrically. Cartilage thickness and BrdU labeling index in the MCC 3, 7, and 14 days after placement of the positioners were compared with those in age-matched controls that received no positioners. Cartilage thickness in the MCC on the protruded side was significantly greater than that in the controls at each time interval, with the difference increasing slightly with time. The labeling index for the protruded MCC was significantly greater than the controls at both 7 and 14 days after positioner placement. Trends on the nonprotruded side were generally opposite, culminating in reduced thickness and proliferation after 14 days. Thickness and labeling index were greater on the protruded side at every time interval except 3 days (labeling index). These trends in cartilage thickness and proliferation are consistent with previous studies of MCC changes after bilateral functional protrusion or retrusion. These data suggest that changes in MCC thickness and proliferative activity might accompany a lateral functional shift of the mandible in growing persons.

Analysis of Variance↗

PubMed2006

Analysis of sagittal condylar path inclination in consideration of Fischer's angle.

This study investigated the sagittal condylar path during protrusive and lateral excursions by analysing the actually measured jaw movement data and re-evaluated the setting of the sagittal condylar path inclination in consideration of Fischer's angle. Protrusive and lateral excursions of 10 healthy subjects were measured using a three-dimensional mandibular movement analysing system. Condylar path inclinations at the hinge-axis point and the corresponding external point laterally extending from the condyle were evaluated in the sagittal plane. Fischer's angle was defined as the difference between the sagittal condylar inclinations during protrusive and lateral excursions on the non-working side, by keeping the corresponding horizontal distance from the intercuspal position (ICP) equivalent at the incisal point. Analysis was performed at three different magnitudes of excursions, where the incisal point was located at 1, 3 and 5 mm away from the ICP. There was no significant difference in the sagittal condylar path inclination or the Fischer's angle between two condylar reference points. However, they were significantly different across the three different magnitudes of excursions for both condylar reference points, i.e. sagittal condylar path inclination (P = 0.003 for protrusive excursion, and P < 0.001 for lateral excursion respectively; two-way repeated-measures anova), and Fischer's angle (P = 0.013, two-way repeated-measures anova) became smaller as the incisal point became distant from the ICP. Moreover, 3- and 5-mm eccentric positions were included in the 95% CI where Fischer's angle equals zero and were considered to be clinically acceptable to adjust the sagittal condylar inclination on the semiadjustable articulators.

Adult↗

PubMed1999

Condylar bony change and craniofacial morphology in orthodontic patients with temporomandibular disorders (TMD) symptoms: a pilot study using helical computed tomography and magnetic resonance imaging.

OBJECTIVE: To investigate how condylar bony changes relate to craniofacial morphology using helical CT and MRI. DESIGN: Craniofacial morphology of orthodontic patients with condylar bony changes was compared with Japanese standard. SETTING AND SAMPLE POPULATION: The Department of Orthodontics, Niigata University School of Dentistry, Twenty-nine subjects were selected from orthodontic patients (six males and 23 females, a mean age of 18.8 +/- 6.3 years) who were diagnosed by helical CT as having condylar bony changes. EXPERIMENTAL VARIABLE: Subjects were divided into two groups: a unilateral condylar bony change group (unilateral group) (four males and nine females) and a bilateral condylar bony change group (bilateral group) (two males and 14 females). OUTCOME MEASURE: Condylar bony changes were evaluated on reconstructed coronal and sagittal CT scans. Disk positions were evaluated by MRI scans. Five linear and four angular measurements in lateral and posteroanterior cephalograms were compared with those of an age- and sex-matched 'standard population' from the Japanese standard. RESULTS: In the bilateral group, osteophyte formation and erosion were the common bony changes and were present in adult as well as juvenile subjects. In the unilateral group, flattening was the most common features and erosion was only present in subjects below 19 years. Disk displacement without reduction was seen in 90.6% of the bilateral group, and in 76.9% of the unilateral group. Retrognathic mandibles were shown in the bilateral group. All subjects exhibited a lateral shift of the menton toward the condylar bony changed side in the unilateral group. CONCLUSION: Condylar bony changes might be progressive and unstable in adults of the bilateral group as well as in juveniles of the both groups. It appears that condylar bony changes may be related to a lateral shift of the mandible and a retrognathic mandible in orthodontic patients with TMD symptoms.

Adolescent↗

PubMed1996

[Conservative versus surgical therapy of unilateral fractures of the collum mandibulae--anatomic and functional results with special reference to computer-assisted 3-dimensional axiographic registration of condylar paths].

A clinical, radiographic and computer-assisted axiographic follow-up was carried out on 60 patients who had been treated for unilateral subcondylar fractures. These were patients of the Department of oral, maxillofacial and facial plastic surgery of the Medical Faculty of the University of Technology in Aachen, Germany. After surgical reduction of the condyle with fixation by osteosynthesis where results were positive, 27 patients exhibited a shortening of the condyle paths on the side operated on by up to 16.4%. Although conservative therapy produced slighter straightening of the condyle with more or less strongly marked condylar deformations in two-thirds of the cases, functionally more positive results were obtained by markedly slighter limitation of the condyle paths on the traumatized side. These results would appear to indicate operative therapy of unilateral subcondylar fractures in the case of luxation fractures, condylar dislocation in excess of 50 degrees, and in those cases where intermaxillary immobilization is not feasible. In the remaining cases, conservative treatment is preferred, due to it showing functionally more positive results.

Adult↗

PubMed2004

Magnetic resonance evidence of joint effusion of the temporomandibular joint after fractures of the mandibular condyle: a preliminary report.

To investigate the clinical significance of magnetic resonance (MR) evidence of joint effusion of the temporomandibular joint after mandibular condylar fractures, magnetic resonance imaging (MRI) was performed on 18 joints in 15 patients with either unilateral or bilateral mandibular condylar fractures using a 1.5 Tesla MRI scanner (Signa, General Electric, Milwaukee, WI). MR evidence of joint effusion was evaluated and compared with the types and the positions of the fractures. MR evidence of joint effusion was observed in 11 of 18 TMJs, which was 61% of the condylar fractures. It appeared more frequently after fractures with dislocation than those without dislocation (p < 0.05). In addition, MR evidence of effusion appeared more frequently in TMJs after high condylar fractures (head to upper neck) than low condylar fractures (lower neck to subcondylar) (p < 0.05). These findings indicate that MR evidence of joint effusion may serve as a marker for the detection of severe intra-articular damage to the TMJ after mandibular condyle fractures.

Adolescent↗

PubMed2005

Mandibular advancement using a retrocondylar cartilage graft: a 20-year prospective study.

We examined the outcome after a mean of 46 months (range 18-204) of 73 patients with severe mandibular retrusion who had surgical advancement of the mandible by a post-condylar cartilage graft. The extent of the mandibular advance and the change in position of the condyle were measured by a previously described cephalometric method. Tomograms of the temporomandibular joint (TMJ) were taken at defined intervals and any changes in the articulation recorded. The mandible was advanced by a mean (S.D.) of 9.8 (3.4) mm. The mean postoperative change recorded on the final cephalometric radiograph was 0.4 (4.7) mm forward (95% CI -0.70 to+1.50). The mandibular condyle was advanced horizontally by a mean 7.2 (2.1) mm and depressed vertically by a mean of 5.9 (2.6) mm. postoperatively the condyle relapsed horizontally by a mean of 1.5mm and moved vertically downward by a mean of 0.2mm. Eleven patients had substantial skeletal relapse. Eight patients were regarded as clinical failures. Skeletal relapse did not always lead to clinical failure because of compensatory mandibular growth. Changes in the condylar region, which contributed to relapse, included condylar absorption and remodelling (n=7) and absorption of the cartilage graft (n=6). There were no postoperative functional problems with the TMJ. We conclude that the post-condylar cartilage graft is a useful technique for the treatment of certain cases of mandibular retrusion. The postoperative morbidity was less than that reported after other techniques of mandibular advancement including distraction. Skeletal relapse was found in more cases than clinical results had suggested.

Adolescent↗

PubMed1988

The biomechanical relation between incisal and condylar guidance in man.

The arrangement, form and movement of incisal and condylar guidance allow representation of the stomatognathic system by a gearing with positive drive and closed linkage. Because of problems of stability, this gearing has to be a throttle crank. Therefore, the stomatognathic elements have to fulfill the condition of Grashoff. The analysis of 14 Class I patient data confirms this condition and yields that their stomatognathic systems seem to be determined by only two parameters. The properties of these systems are largely independent of the jaw's growth if the momentary growth takes place in the direction of the initial inclination of hinge-axis movement out of centric relation.

Biomechanical Phenomena↗

PubMed1989

Transferring anterior occlusal guidance to the articulator.

Anterior disclusion has become accepted as an optimal therapeutic model in the restoration of the anterior dentition. The ability to achieve anterior disclusion is influenced by the anterior determinants of esthetics, phonetics, skeletal relation, tooth position, abutment distribution, and alveolar bone support in addition to the posterior condylar determinants. Temporary restorations are made to incorporate these factors and it becomes necessary to transfer the information to working models of the articulator. A technique is described whereby a wax or silicone index fixed partial denture is made at chairside, duplicating the temporary restoration that is directly transferable to the working casts of the articulator. This technique allows the technician to make final restorations according to the index fixed partial denture, thus incorporating the anterior determinants of occlusion in conjunction with the posterior condylar determinants specific to each patient.

Dental Articulators↗

PubMed1998

Condylar remodelling and resorption after Le Fort I and bimaxillary osteotomies in patients with anterior open bite. A clinical and radiological study.

A sample of 259 patients with vertical maxillary hyperplasia, mandibular hypoplasia and anterior vertical open bite, collected from three different institutions, was analysed regarding temporomandibular joint (TMJ) sounds, condylar remodelling, and condylar resorption. All patients underwent Le Fort I osteotomies, and bilateral sagittal split advancement osteotomies were performed in 117 patients. Intraosseous wire fixation was used in 149 and rigid internal fixation in 110 patients. Cephalometric and orthopantomographic radiographs were available before surgery, immediately after surgery, one year postoperatively and at the latest follow up. The mean follow up was 69 months (range 20-210 months). The number of patients with TMJ sounds decreased from 38% to 31%. At the latest follow up 23.6% of the patients showed condylar remodelling, 7.7% unilateral condylar resorption and 7.7% bilateral condylar resorption. Condylar contours, as assessed on orthopantomographic radiographs, were classified as five different types. Condyles with preexisting radiological signs of osteoarthrosis or having a posterior inclination were at high risk for progressive resorption. Female patients with severe anterior open bite, high mandibular plane angle and a low posterior-to-anterior facial height ratio, who underwent a bimaxillary osteotomy, were prone to condylar resorption. Bone loss was predominantly found at the anterior site of the condyle. The incidence of condylar resorption was significantly higher after bimaxillary osteotomies (23%) than after only Le Fort I intrusion osteotomies (9%). Avoidance of intermaxillary fixation by using rigid internal fixation tended to reduce condylar changes, in particular in patients who underwent only a Le Fort I osteotomy. Rigid internal fixation in bimaxillary osteotomies resulted in condylar remodelling in 30% and progressive condylar resorption in 19% of the patients. Condylar changes were not significantly different after using either miniplate osteosynthesis or positional screws in bilateral sagittal split osteotomy procedures.

Adolescent↗

PubMed2003

Lateral functional shift of the mandible: Part II. Effects on gene expression in condylar cartilage.

There is considerable evidence that proliferation and growth in the mandibular condylar cartilage (MCC) might be altered after a change in the postural position of the mandible. However, almost nothing is known about the molecular basis of this response. Using semiquantitative reverse-transcription polymerase chain reaction, we examined the expression of insulin-like growth factor-1 (Igf-1), fibroblast growth factor-2 (Fgf-2), and their receptors (Igf-1r, Fgfr1, Fgfr2, and Fgfr3) in the MCC of 28 day-old rats at 3, 7, and 14 days after placing intraoral appliances designed to produce a lateral functional shift of the mandible. This shift resulted in a transverse rotation of the mandible so that the condyle on the side away from the shift was distracted anteriorly (ie, protruded) from the glenoid fossa, while the contralateral condyle remained in place or moved slightly posteriorly (ie, nonprotruded). Gene expression for 5 of the 6 genes studied was significantly different (P <.05) between the protruded and the nonprotruded sides. In nearly every instance at the 3- and 7-day intervals, mRNA expression on the protruded side compared with age-matched controls was altered in the opposite direction from the nonprotruded side. Especially on the protruded side, the most pronounced differences from the control were evident at 3 and 7 days. In general, the changes in gene expression preceded the alterations in proliferative activity documented previously. These data suggest that alterations in the mRNA expression of Igf-1, Fgf-2, and their receptors might underlie in part changes in MCC proliferative activity after alteration in mandibular posture.

Animals↗

PubMed1994

Condylar height on panoramic radiographs. A methodologic study with a clinical application.

The aim of this study was to develop and apply a reliable method of measuring the effects of condylar lesions quantitatively on panoramic radiographs. Three different types of machines were tested. Two dry skulls were exposed in six positions in each machine, and the relative size of the condyle in relation to ramus height was calculated. The results showed good validity for the reference points used. The head position did not contribute to the variation in the measurements, but the type of panoramic machine had some influence. It was concluded that the method may be applied when calculating condylar ratios, provided that the same panoramic machine is used. The relative height of the condyle in relation to ramus height was measured bilaterally in three groups of children, with either normal or postnormal occlusion or with juvenile chronic arthritis (JCA), to detect possible asymmetries and define differences in the relative condylar height. The JCA group had a significantly shorter relative condylar height, and asymmetries were commoner than in the other two groups.

Adolescent↗

PubMed1989

[Involvement of the temporomandibular joint in rheumatoid arthritis].

A tomographic investigation was performed on 51 randomly-selected rheumatic patients, according to American Rheumatism Association criteria. Fourteen males and 37 females, aged 26 to 73 (mean age 50.9) were examined in order to identify the prevalence of temporo-mandibular joint involvement. By means of a special examination form, a contemporary clinical survey of both signs and symptoms of mandibular dysfunction was also conducted: the data were used for calculating the Helkimo anamnestic and clinical dysfunction indices. As for X-ray diagnosis, and original linear and angular analysis was proposed to measure the relationship between condyle and fossa in intercuspal position and during opening: the anterior joint space often increased and protrusive condylar path was reduced in more than 41% of patients. Structural changes were also evaluated by classifying the shape of both the condyle and the glenoid fossa (rounded, wedge-shaped and flattened). A special score was used to quantify these morphological features: only 4% of the whole of joints resulted uninjured. The most involved joint portions were the articular tubercle and the anterior condylar pole. Many cases were demonstrated of marked resorption and remodelling of the condyle, of increased joint space and erosion of the fossa; in other instances, reduced joint spaces and sclerosis were observed, depending on associated degenerative arthritis (usually more painful). Sex and age differences were not significant. Severity of clinical dysfunction and seriousness of the lesions coincided, whereas subjective symptoms were relatively independent. At any rate, the survey demonstrated a clear prevalence of structural, as well as functional, involvement of the temporo-mandibular joint in rheumatoid arthritis and suggested a more careful and multimodal therapeutic approach.

Adult↗

PubMed1989

[Precision of semiadjustable articulators].

The precision of 11 semiadjustable articulators was examined. The results indicate that for reproducible centric position it is necessary to practise centric lock. Neither guidance of the condylar element into centric relation by hand nor devices like feathers do secure against deviation. When putting usual pressure on the articulators all showed considerable differences.

Dental Articulators↗

PubMed1994

[Involvement in morphological changes of the articular cartilage of rat temporomandibular joint induced by experimental malocclusion].

The effect of malocclusion induced by increase in unilateral occlusal vertical dimension on the articular cartilage of rat mandibular condyle was histologically and immunohistologically examined. WKA rats (8 weeks) were divided into three group A: untreated (control) rats, group B: rats forced to mouth open just for 20 min, and group C: rats given malocclusion by putting the 1 mm diameter wire on the right upper molar continuously. After treatment, each rat was sacrificed periodically up to 9 weeks, and the morphological changes of condylar cartilage (articular, embryonic and transitional zones of cartilage layer) were histologically investigated. The thickness of articular cartilage in all groups was decreased in a time-dependent manner (up to 9 weeks after treatment). In group C rats, whose articular cartilage was thinnest in three groups, the reduced thickness of cartilage in the non-treated side (the left side) was same as that in the treated side which was presented with excessive molar contact. But, its occurrence in the treated side was seen 2 weeks earlier than that in the non-treated side. Even in group B rats which were only forced to open the mouth for 20 min without setting of permanent malocclusion, the thickness of condylar cartilage was decreased more than that of group A rats. When the condylar cartilages of all three groups were immunohistologically examined with anti-interleukin-1 (IL-1) antibody in order to investigate the pathophysiological involvement of IL-1, which is well-known catabolic factor to cartilage, some chondrocytes in articular cartilage were positively stained. The ratio of IL-1 positive cells increased time-dependently. IL-1-producing cells in group B and the non-treated side of group C reached to the maximal ratio at the same time when the condylar cartilage markedly decreased in thickness. However, the ratio of IL-1-positive chondrocytes in the treated side of group C was maximal four weeks after the decrease of cartilage thickness. In respect with the size of cells in cartilage, the occurrence of decreased thickness in condylar cartilage corresponded to that of the reduction of cellular size, especially in the embryonic zone of group C. These results described above suggest that malocclusion, unilateral immature occlusion, can induce the thinning of condylar cartilage which may result from the reducing size of articular chondrocytes (differentiated chondrocytes) and the accompanying decreased cartilage matrix. This change of cartilage may be caused by IL -1 that articular chondrocyte seemed to produce.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1975

Treatment methods in tibial condylar fractures.

A series of 915 tibial condylar fractures has been analyzed for the type of treatment used and some of the pitfalls encountered with emphasis on preservation of fracture position. The most commonly used treatment methods are discussed in depth, emphasizing the advantages and disadvantages of each and their indications in the various types of tibial condylar fractures. It is concluded that the treatment must be carefully fitted to the type of fracture and to the patient in order to achieve a strong movable knee with good alignment and stability.

Bandages↗