Jaw function status in an elderly community sample.
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C A Bibb
Publications and source records attributed to C A Bibb.
Histologic characteristics of the lateral pterygoid muscle insertion to the temporomandibular joint.
This study used low-power light microscopy to examine the histologic organization of the lateral pterygoid muscle interface with the temporomandibular joint. The sample included parasagittal sections of 20 intact temporomandibular joints from young adults (mean age 26.2 years) at autopsy. The lateral pterygoid muscle showed no consistent divisions into separate anatomic muscle heads at the insertion. The muscle fibers attached to the pterygoid fovea of the condyle immediately inferior to the articular surface in all cases. Some additional fibers inserted superiorly into the more anterior part of the articular disc in a minority of cases (31%). Fibers inserting into the disc represented only 2.4% to 6% of the total superior-inferior length of the muscle insertion. It is hypothesized that the muscular force exerted by these few fibers inserting into the disc would not be sufficient to displace the disc anteriorly to the condyle. There were two histologic types of insertion of the lateral pterygoid muscle to the condyle. The superior part of the insertion was characterized by an identifiable tendon inserting through fibrocartilage. In the inferior part of the insertion, the muscle attached to periosteum without an obvious tendon. The presence of this tendon must be recognized in interpretation of soft tissue temporomandibular joint imaging.
Adolescent↗
Serial variation in histological character of articular soft tissue in young human adult temporomandibular joint condyles.
Histological variation was studied in serial sections, in contrast to previous studies which have generalized from representative sections. The sample consisted of consecutive serial sagittal sections from the central third of nine condyles, plus an accompanying stone cast showing the intact articular surface before sectioning. The thickness of the articular soft tissue and its fibrous connective tissue and cartilage components was measured, and the presence of undifferentiated mesenchymal (UM) cells was assessed by low-power light microscopy. Components of variance analysis showed that section-to-section variation in thickness was of the same order as differences between joints, each explaining approx. 50% of the variance in both connective tissue and cartilage thickness. The fibrous connective tissue contributed as much to the overall variation in soft tissue thickness as did the cartilage component (SD 0.0946 versus 0.0909 mm for the superior sector). Serial UM cell variability was common, and the UM cells were often distributed in islands rather than uniformly across the articular tissue. Condyles with the greatest surface irregularity were characterized by greater serial variability in fibrous connective tissue thickness, more frequent absence of cartilage, and more areas of UM cell depletion. These results suggest that serial variation in histological character may be more important than mean values in the description of surface contours and articular tissue relations in the temporomandibular joint. This should influence the design of future investigations.
Adult↗
Contour mapping of the TMJ temporal component and the relationship to articular soft tissue thickness and disk displacement.
The osseous architecture of central sagittal histologic sections of the temporal component of 51 temporomandibular joints of young adults at autopsy was studied to determine if this predicted the thickness of the overlying articular soft tissue and disk displacement. Geometric groupings of fossa-eminence shapes were generated using a hierarchical cluster analysis of the osseous fossa-eminence sigmoid curve, size, and slope. Six cluster groups were evolved and tested for relationship to soft tissue thickness measured at the eminence crest, mid-point of the eminence slope, closed pack location of the condyle, the inflection point, and the depth of the fossa. Soft tissue thickness at the inflection point and depth of the fossa was remarkably constant between cluster groups. Increased soft tissue thickness at the eminence crest and lower part of the posterior slope was weakly correlated to a flatter eminence slope and curve, explaining 10% to 20% of the variance (r2). There were no relationships between the parameters studied to the fossa curvature. An ANOVA showed no statistical difference in the posterior slope angle between the categories of disk position (p = 0.715) or to the six cluster groupings. The results suggest that the osseous contours seen on radiographs may not accurately predict the actual articular surface of the temporal component.
Adolescent↗
Relationship of articular soft tissue contour and shape to the underlying eminence and slope profile in young adult temporomandibular joints.
This study examined whether the overall shape of the articular soft tissue overlying the posterior slope and articular eminence of the temporal bone could be predicted by the underlying osseous contour in a histologic model of 51 central sagittal sections of young adult temporomandibular joints. Articular soft tissue and bone contours were traced, and osseous landmarks identified on the basis of joint geometry. Soft tissue thickness measurements were made under low power light microscopy. Seven categories of articular soft tissue pattern were identified. The soft tissue uniformly followed the osseous contour in only one (14%). A progressive increase in soft tissue thickness from the middle of the posterior slope to the articular crest was the most common pattern (35%) but did not describe most of the sample that was more asymmetric. Pattern was poorly predicted by the shape and slope of the temporal bone outline or by dental factors that describe anterior guidance and did not relate to disk displacement. The articular soft tissue compensated for flatter eminence slopes and osseous irregularities and maintained an intact surface. This study has clinical implications for radiographic interpretation of disk space, condyle translation pathways, and the integrity of the functional articular surface.
Adolescent↗
The articular-synovial lining tissue system in temporomandibular joints of young adults.
The histologic character of the articular surfaces and synovial tissues in the temporomandibular joints of 20 young adults was described. Each joint compartment had a continuous connective-tissue lining that was fibrous on the articular surfaces, went through a transition, and was continuous with the lining tissue in the recesses. Areolar synovial tissue was found only in the upper posterior recess of the temporomandibular joint, fibrous synovial tissue was predominantly found in the upper anterior and lower posterior recesses, and an intermediate type of synovial tissue was found in the lower anterior recess. There was no distinct boundary between articular and synovial tissue. The structure and continuity of these lining tissues suggest that they constitute a continuous tissue system, here termed the "articular-synovial lining tissue system," that has a histologic character which depends on location and functional demands. It is hypothesized that all of the lining tissues should be considered synovial, based on a functional definition of nonadherence.
Adolescent↗
The relationship of undifferentiated mesenchymal cells to TMJ articular tissue thickness.
Undifferentiated mesenchymal (UM) cells, the progenitor cells of the cartilage layer, have been assigned a significant role in TMJ articular tissue maintenance. This was based on reports of UM cell reduction with increased soft-tissue thickness for the condyle and temporal component. However, the strength of this inverse relationship was not presented and remained unclear. The purpose of the present study was to assess the strength of the correlation between UM cell presence and soft-tissue thickness in young adult TMJs at autopsy. Sagittal histological sections from the central thirds of 50 joints were evaluated with respect to articular soft-tissue thickness, histological character, and UM cell presence in the condyle and temporal component. The superior sector of the condyle and the articular eminence showed the greatest variability in soft-tissue thickness and were the only areas to show localized UM cell absence. The eminence was the only location to show an inverse relationship between soft-tissue thickness and UM cell presence, and this was consistent in both an ANOVA (p = 0.0016) and a Spearman correlation analysis. However, the strength of this correlation was only moderate (rho = -0.52), and no such relationship was observed in any other location. This study suggests that the relationship between UM cell presence and soft-tissue thickness is more complex than previously hypothesized and that the contribution of UM cells to articular tissue maintenance has been overstated, while other biological processes were overlooked.
Adaptation, Physiological↗
Relationship of TMJ articular soft tissue to underlying bone in young adult condyles.
This investigation used a histological model to study the relationship of articular soft-tissue thickness and contour to the underlying bone in the TMJ condyle of young adults. The usefulness of selected dental and demographic factors in the prediction of the articular soft-tissue thickness and contour was also tested. One sagittal histological section was studied from the lateral, central, and medial thirds of 53 left mandibular condyles. Outline tracings of the articular and compact bone surface were divided into anterior, superior, and posterior sectors for the study of curvature measured by the overlaying of a template of a harmonic series of arcs. The thickness and composition of the articular tissues were measured in each sector by light microscopy. The fibrous connective tissue layer always maintained the articular surface, even in the absence of a cartilage layer. The histological character, including the presence or absence of cartilage, rather than the overall tissue thickness, was considered to be a more useful marker of functionally thickness was not related to surface deviation in form and was not correlated with age in this young adult sample. Reduced soft-tissue thickness in the anterior part of the condyle was more common in cases with lack of molar support. Dental attrition was not a useful predictor of soft-tissue thickness. Compact bone contour correlated with soft-tissue contour in the superior (r = 0.816) and posterior (r = 0.808) sectors, explaining only 64% of the variance, but not in the anterior sector (r = 0.265). Thicker or thinner articular soft tissue was not predictable by the underlying compact bone contour or thickness. Therefore, the clinician should not automatically assume that the radiographic osseous image represents the actual articular surface.
Adolescent↗
Distribution and histologic character of osseous concavities in mandibular condyles of young adults.
Osseous concavities at the bone--articular soft-tissue interface were identified in 23% of 53 young adult TMJ condyles, with most occurring in the superior sector of the lateral and central aspects. All were filled with articular soft tissue, which provided a smooth articular surface without any evidence of surface breakdown. By extrapolation, radiographic evidence of osseous concavities in this age group should not be interpreted as evidence of articular surface breakdown (arthrosis). The long-term outcome of these concavities cannot be determined from this histologic cross-sectional study. However, the results support initial conservative therapy with monitoring over time.
Adolescent↗
Relationship of condylar bone profiles and dental factors to articular soft-tissue thickness.
The relationship between articular soft-tissue thickness and condylar bone profiles, compact bone thickness, and deviation in form was studied in central sagittal sections from 53 human temporomandibular joints. Because of the absence of normal standards, several definitions of thickness were used. The angular bone profiles had a higher probability of having thicker soft tissue in the superior sector (59%) than the other profiles. An ANOVA to test for soft-tissue thickness differences between profiles approached significance for the angular profile in the superior sector (P = 0.049). Neither compact bone thickness nor deviation in form had an observable relationship with articular soft-tissue thickness, probably because of the dynamic state of the articular tissues in young adult temporomandibular joints. The distribution of categories of articular soft-tissue thickness was not related to dental attrition; however, there was some skewing toward reduced soft-tissue thickness in the anterior sector in the group with loss of molar support.
Adolescent↗
Temporomandibular joint comparative imaging: diagnostic efficacy of arthroscopy compared to tomography and arthrography.
This comparative imaging study of the TMJ was conducted to examine the diagnostic data obtained from arthroscopy as compared to data from tomography and arthrography. Six joints from cadaver material were imaged by each technique and subsequently dissected. Each technique had value, but none was comprehensive. Tomography was the technique of choice for imaging osseous changes. Double joint space arthrotomography was useful for examining articular disk position and morphology. Diagnostic arthroscopy, through direct visualization of surface morphology, showed localized surface pathosis, such as synovitis; provided data on the location and size of disk perforations; and contributed reliably to a diagnosis of disk displacement on the basis of associated pathosis such as stretching of the posterior attachment.
Arthrography↗
Malocclusion associated with temporomandibular joint changes in young adults at autopsy.
The purpose of this study was to identify variables of malocclusion that might be associated with previously reported temporomandibular joint morphologic findings. Before removing the left TMJ from each of 96 cadavers (age means equals 26.4 +/- 6.8 years), an intraoral examination was performed. Angle classification, crossbite, overbite, and overjet were evaluated. These parameters were analyzed with respect to their association with the following TMJ features: overall shape of the condyle and temporal bone, gross and histologic evidence of remodeling, and position of the articular disk. When combined with age, Angle Class II and III dentitions were associated with temporal and condylar deviation in form (DIF) (P less than 0.05) and more Class II dentitions were accompanied by histologic evidence of remodeling changes in the TMJs. Crossbite was associated with increasing presence of DIF in all components (P less than 0.01). Anterior crossbite was associated with DIF on the articular eminence (P less than 0.01). Deep overbite was more common in persons with flat condyles, open mandibular fossae, and anterior extension of the temporal articular surfaces (P less than 0.05). Abnormal overjet was more evident in those with DIF in the disk (P less than 0.05); greater overjet was associated with disk displacement (P less than 0.05). Considered together, abnormal overbite and overjet were associated with more extensive DIF on the condyle (P less than 0.05). In conclusion, malocclusion was associated with morphologic changes in the TMJ, particularly when combined with age. This evidence supports the belief that longer exposure to malocclusion may be associated with more extensive TMJ changes.
Adolescent↗