Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MANDIBULAR CONDYLE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,441 records · Page 80Linked to original sources
PubMed1994

Articular disc and eminence modeling after experimental relocation of the glenoid fossa in growing rabbits.

The articular surface of the glenoid fossa shows some analogy to the mandibular condyle, since the surface is covered by secondary cartilage, which makes the process more elastic than purely bony structures. The condylar cartilage has been shown to be responsive to alterations in load pressures, and this secondary type of cartilage is also able to increase its proliferative activity to a limited extent when the load pressure is altered. The aim here was to measure changes in proliferative activity and type II collagen secretion in the articular surface of the glenoid fossa after steady experimental posterior relocation of the fossa in the rabbit without actively interfering with normal masticatory action. The shape of the articular disc and interrelations of the joint components were measured macroscopically. Twenty-four five-day-old rabbits underwent gluing of the interparietal, temporoparietal, and lambdoidal sutures. Three experimental and 3 control rabbits were injected with tritiated thymidine at 10, 15, 20, and 30 days and were killed after 2 h for histological, autoradiographic, and immunohistochemical examination. The total number of labeled cells in the proliferative layer near the articular eminence was higher in the experimental group, the difference being greatest in the 15- and 20-day-old rabbits. Immunohistochemical examination revealed less staining for type II collagen on the postero-inferior side of the eminence in the experimental group. The articular disc was flattened in the experimental group, and the elastic tissue bundle connecting the articular eminence and the anterior border of the disc was significantly narrower and longer.

Age Factors↗
PubMed1994

Perichondrial and endochondral components of mandibular condylar growth: morphometric and autoradiographic quantitation in rats.

In an attempt to determine the contribution of the perichondrial and endochondral components to rapid and slow overall condylar growth, mandibular condyles from rats aged 21 and 45 d as well as 3 and 6 months were examined by light microscopy. A morphometric analysis served to estimate the size of cells and the amount of extracellular matrix per cell in the various tissue layers beneath the articular surface. Quantitative evaluation of autoradiographic labelling due to the presence of [3H]-thymidine, [3H]-proline, and [35S]-sulphate 1.5 or 2 h and 5 d after injection of the tracer was used to determine the velocity of overall condylar growth. A combination of the two types of results allowed the calculation of daily rates in (1) the generation of new chondrocytes, constituting the perichondrial growth component, and the endochondral components comprising (2) net accumulation of extracellular matrix in the cartilage and (3) enlargement of the chondrocytes. It was observed that the 3 factors contributed, respectively, by about 10-25, 30 and 45-60% to rapid growth and by about 75, 15 and 10% to slow growth. Thus when growth slowed, the contribution of chondrocyte enlargement declined markedly and that of matrix accumulation slightly, while the contribution of new cell generation increased correspondingly. Declines in chondrocyte enlargement and in accumulation of cartilage matrix that was related mainly to decreasing proteoglycan formation were in good agreement with age-associated variation in weight gain, while peak rates in generation of new chondrocytes appeared to be delayed against peak somatic growth. It is concluded that (1) endochondral components contribute most to particularly rapid condylar growth, exceeding the perichondrial component, and (2) endochondral components of condylar growth are regulated by systemic factors that also control somatic growth.

Animals↗
PubMed2000

Effect of metabolic acidosis on the growth hormone/IGF-I endocrine axis in skeletal growth centers.

BACKGROUND: Chronic metabolic acidosis (CMA) adversely affects bone metabolism and skeletal growth. Given the cardinal role played by the local growth hormone (GH)/insulin-like growth factor-I (IGF-I) in promoting cell proliferation and differentiation in growth plates, we tested the effect of CMA on the GH/IGF-I axis in a skeletal growth center. METHODS: We employed an in vitro organ culture system using the murine mandibular condyle as a model for endochondral active growth center. Condyles from six-day-old ICR mice were cultured in BGJb medium of either neutral pH (pH approximately 7.4) or acidic pH (pH approximately 7.15). After 24, 48, 72, and 96 hours of culture, the condyles were washed, fixed in formaldehyde, and processed for paraffin embedding. We assessed histologic markers of the growth center. In addition, the protein level and mRNA expression for the different components of the GH/IGF-I axis were evaluated by immunohistochemistry and in situ hybridization, respectively. Finally, we evaluated the effect of acidosis on the biological functions mediated by GH and IGF-I (namely, proliferation and differentiation of cartilage cells in the active growth center). RESULTS: Following three to four days in acidic conditions, there was a marked reduction in the size of young chondrocytic population, suggesting a defect in the process of endochondral differentiation. Immunohistochemistry and in situ hybridization analyses revealed a marked reduction in the expression of the IGF-I receptor, as well as in the GH receptor. These changes were already evident after 48 hours of incubation in acidic conditions. At 48 hours of acidosis, there was also a marked reduction in the expression of IGF-I both under basal conditions (nonstimulated) and following stimulation with GH. The expression of IGF binding protein 2 (IGFBP-2) and IGFBP-4, which serve as negative modulators of IGF-I, was enhanced in CMA. IGF-I markedly stimulated chondrocytic proliferation (assessed by BrdU incorporation into DNA) and differentiation (assessed as cartilage specific proteoglycan expression). These responses were markedly attenuated in acidic conditions. CONCLUSION: CMA exerts an anti-anabolic effect in bone growth centers, which is partly related to a state of resistance to GH and IGF-I, created by CMA. This phenomenon may underlie the disturbance in longitudinal bone growth in CMA (that is, renal tubular acidosis) and may contribute to renal osteodystrophy in patients suffering from chronic renal failure.

Acidosis↗
PubMed1999

Electromyographic activity of the human lateral pterygoid muscle during contralateral and protrusive jaw movements.

Understanding of the normal function of the lateral pterygoid muscle is limited. The principal aim here was to determine whether there is a progressive increase in lateral pterygoid activity as the mandibular condyle moves downwards and forwards as would be expected if the muscle is concerned with the precise horizontal positioning of the mandible. In eight humans, recordings were made of the activity of the superior (SHLP) and inferior (IHLP) heads of the lateral pterygoid and the masseter, anterior temporal, posterior temporal and digastric muscles, together with the movement of the palpated lateral condylar pole (JAWS-3D tracking system) during trials of a contralateral and a protrusive jaw movement. Recording sites in SHLP and, in one participant, IHLP were verified by computed tomography. In each participant there was a progressive increase in the rectified and smoothed SHLP and IHLP activity in association with condylar movement during the contralateral and protrusive jaw movement. Further, irregularities in condylar movement, which reflected variations in the rate at which the jaw was moved, were correlated in time with prominent bursts of SHLP and IHLP activity. In all participants there was a consistently high correlation coefficient between the rectified and smoothed SHLP and IHLP activity and condylar displacement during the contralateral or protrusive jaw movements. For example, the mean (+/-SD) correlation between anterior condylar translation during contralateral excursion and SHLP activity was 0.91+/-0.09, and for IHLP 0.96+/-0.02. For the masseter, anterior temporal, posterior temporal and digastric muscles, mean r-values were, respectively, 0.10+/-0.77; -0.14+/-0.72; 0.24+/-0.78; 0.54+/-0.47. When treated as a group the correlation coefficients for SHLP and IHLP were statistically significantly different from the correlation coefficients for the other muscles treated as a group (ANOVA; p < 0.002 for correlation with anterior translation). These observations support the notion that the lateral pterygoid provides the principal driving force for moving the jaw forwards or laterally in protrusive or lateral excursive condylar movements. Further, the data suggest that the muscle plays a part in the fine control of jaw movements.

Adult↗
PubMed1986

An unusual function for the medial pterygoid muscle in the guinea pig.

This muscle has some physiological properties resembling those of jaw-opening muscles. Biomechanical analysis showed that, because of the anatomical peculiarities of the feeding apparatus in caviid rodents, the action of the muscle changes from closing to opening as the mandibular condyles are protruded in the groove-like mandibular fossa. This unusual changing function may be useful in producing the ventral, medial and anterior power stroke of mastication.

Animals↗
PubMed2004

Occlusal difficulties after simultaneous mandibular and maxillary distraction in an adult case of hemifacial microsomia.

A 23-year-old woman with hemifacial microsomia type IIB was treated by simultaneous mandibular and maxillary distraction. During the course of the distraction, cephalometric analysis showed that the maxilla was not moving downward and that the upper edge of the mandibular condyle was moving upward into the space between the condyle and the glenoid fossa. This phenomenon could lead to early consolidation of the osteotomized maxilla, resulting in malposition and occlusal difficulties. This is thought to be a problem unique to bimaxillary distraction of hemifacial microsomia type IIB with severe hypoplasia of the mandibular ramus and space between the condyle and the glenoid fossa. Surgeons should be alerted to this risk and prepared to address it when performing this procedure.

Adult↗
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↗
PubMed2005

Stem-cell-driven regeneration of synovial joints.

Mammalian skeletal motion is made possible by synovial joints. Widespread suffering from arthritis and joint injuries has motivated recent effort to regenerate a stem-cell-driven synovial joint condyle implantable in total joint replacement. A single adult stem cell lineage, mesenchymal stem cells, differentiate to form all components of a synovial joint. Whereas localized joint lesions may be repaired by either cell-based or cell-free approaches, regeneration of the entire articular condyle of the synovial joint is unattainable without tissue-forming cells. A series of experiments are presented here to describe our initial attempts to regenerate a synovial joint condyle in the shape and dimensions of a human mandibular condyle, with both cartilaginous and osseous components derived from a single population of rat mesenchymal stem cells. Upcoming challenges are along several intertwining fronts including structural integrity, tissue maturation, mechanical strength and host integration. The synovial joint condyle may turn out to be one of the first 'human body parts' or organs truly regeneratable by stem-cell-derived approaches. Current approaches to regenerate the synovial joint condyle from stem-cell-derived multiple cell lineages may also offer clues for engineering complex organs such as the kidney or liver.

Animals↗
PubMedDate not supplied

Postanesthetic temporomandibular joint dysfunction.

Internal derangements, myofascial pain dysfunction, and chronic dislocation of the temporomandibular joint (TMJ) are three common sequelae resulting from mandibular trauma. Etiologic factors include prolonged dental and otolaryngologic procedures, and intraoperative use of the laryngoscope and bronchoscope. Three cases are reported to document postanesthetic TMJ dysfunction arising from normal preoperative joints. Four types of TMJ dysfunction are discussed: anterior meniscus dislocation with reduction, anterior meniscus dislocation without reduction, dislocation/subluxation of the mandibular condyle, and myofascial pain dysfunction syndrome. Preoperative screening of mandibular function is recommended in identifying patients as either normal or having potential TMJ dysfunction. Failure to recognize postoperative TMJ dysfunction can lead to long-term symptoms that are difficult to alleviate. Litigation is a common sequel in these cases.

Adult↗
PubMed1987

[Experimental factors influencing the growth of the jaws].

An experimental study evaluated the effect of various surgical procedures on maxillary growth. Raising and excision of palatine muco-periosteum did not modify facial or palatine growth. Resection of the bony palate showed the non-essential nature of the medial palaxine suture during normal growth, even in the transverse direction. Coagulation of the two posterior palaxine arteries disturbed palaxine growth, but ligature of the external carotid artery failed to alter facial growth. Several tests were carried out to determine the importance of functional matrices: excision of facial nerve trunk did not affect bone growth, destruction of the trigeminal provoked obvious disturbance of craniofacial growth while obturation of a nasal fossa produced no observable anomaly. Enucleation demonstrated the need for an intact globe for normal orbital growth, and resection of the mandibular condyle showed the primordial role of cartilaginous centers in mandibular growth.

Animals↗
PubMed1987

Temporomandibular joint morphology in two Australian aboriginal populations.

The morphology of the temporomandibular joints in two Australian populations with previously established differences in patterns of tooth wear and craniofacial morphology did not differ significantly from that described in other comparable populations. The relationships between age and linear and angular measures of joint form were generally not significant, but the shape of the mandibular condyle was age-related, with flattening and cavitation of the posterior and medial aspects being more common in older age groups. Comparison of tooth-wear data in groups with different mandibular condylar shapes suggested that rapid anterior tooth wear was associated with flattening or cavitation of the condyle, while relatively rapid posterior tooth wear was more commonly associated with a convex condylar shape.

Adult↗
PubMed1995

Prenatal growth of the human mandibular condylar cartilage.

The question of whether the condylar cartilage possesses a growth potential like that of the long bone growth plates has been the subject of contrasting viewpoints. We have recently established that the thickness of the human tibial growth plate progressively decreases during the second half of the fetal period, but that the changes in the total human condylar thickness do not correlate with fetal age or weight. The present study examined the change in the thickness of the human mandibular condyle layers during the fetal growth of the mandible. Mandibles were obtained from autopsy of 19 human fetuses ranging in fetal age from 18 to 41 weeks. The total length of the mandible, the lengths of the mandibular body and of the ramus were measured, as well as the gonial angles. The total thickness of the condyle, and the thickness of the articular, progenitor, cartilage, chondroblast, and hypertrophic chondrocyte layers were measured on the central segment of central sagittal sections of the mandibular condylar cartilage. The total mandible, the corpus and the ramus lengths increased linearly with the age of the fetus and they all correlated strongly with fetal weight. However, changes in the total condylar thickness and in the thickness of the cartilage layer (chondroblast plus hypertrophic chondrocytes) did not correlate with fetal weight or mandibular length. The thickness of the articular layer increased with weight, but changes in the progenitor layer were independent of corporal and mandibular growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Cartilage, Articular↗
PubMed2003

[Bruxism, temporo-mandibular dysfunction and botulinum toxin].

Tooth grinding and tooth clenching are unvoluntary mainly nocturnal habits that result in an hypertrophy of masseter and temporalis muscles with an unbalance between opening and closing muscles of the jaw and lead to an alteration of mandibular condyles movements and to hyper pressure in the temporo-mandibular joints (TMJ) which can generate severe pain. Intra muscular injections of botulinum toxin permit to restablish the balance between closing and opening muscles, to relieve pain, to treat masseteric hypertrophy with improvement of face outline and to recover a normal cinetic of temporo-mandibular joints. Moreover, botulinum toxin injections permit to quit habits of tooth grinding and clenching and one single session of injections is curative for 2/3 of the patients. There are no side effects apart from slight diffusion to superficial muscles of the face resulting in a "fixed" smile for about 6 to 8 weeks. So injections of botulinum toxin in masseter and temporalis muscles are an efficient treatment of bruxism and TMJ dysfunction, cheap with no lasting side effect.

Anti-Dyskinesia Agents↗
PubMed2006

Morphometric analysis of the mandible in subjects with Class III malocclusion.

This study evaluated the deformations that contribute to Class III mandibular configuration, employing geometric morphometric analysis. Lateral cephalograms of male and female groups of 100 young adults and 70 children with Class III malocclusion were compared to those of counterparts with normal occlusion. The sample included an equal number of both genders. The cephalographs were traced, and 12 homologous landmarks were identified and digitized. Average mandibular geometries were generated by means of Procrustes analysis. Thin-plate spline analysis was then applied to mandibular configurations to determine local form differences in male and female groups of adults and children with normal occlusion and Class III mal-occlusion. The mandibular morphology was significantly different between these two groups of male and female adults, and children (p < 0.0001). This spline analysis revealed an anteroposterior elongation of the mandible along the condylion-gnathion axis, showing an extension in the regions of the mandibular condyle and ramus, and of the anteroinferior portion of the mandibular symphysis in Class III groups. More extension was evident in Class III adults. The deformations in subjects with Class III malocclusion may represent a developmental elongation of the mandible anteroposteriorly, which leads to the appearance of a prognathic mandibular profile.

Adolescent↗