Histochemical study of the elastic fibers in pathologic human temporomandibular joint discs

Purpose: This study investigated histochemically the elastic fibers in huma n temporomandibular joint (TMJ) discs with varying degrees of tissue degene ration/regeneration to determine whether there are differences that correla te with the histologic findings. Materials and Methods: Ten diseased human TMJ discs and 2 control specimens were studied histochemically by staining with Weigert's resorcin-fuchsin a fter oxidation with peracetic acid. This technique selectively stains elast ic, elaunin, (pre-elastic), and oxytalan fibers. Results: In TMJ discs with an abnormal collagen fiber arrangement, an incre ased number of oxytalan fibers could be observed, contrary to discs with sc ar-like tissue transformation in which oxytalan fibers were decreased in nu mber. In discs showing tears and clefts, the oxytalan fibers run perpendicu lar to the defects, whereas elaunin and elastic fibers were mainly circumfe rentially arranged. In discs with chondroid metaplasia, elastic, elaunin, a nd oxytalan fibers were extensively detected. Conclusions: It is hypothesized that the elastic, elauinin, and oxytalan fi bers found in severely damaged discs appear to ensure biomechanical complia nce by reinforcing regions devoid of collagen bundles and thus function as shock absorbers of stretch and compression. (C) 2001 American Association o f Oral and Maxillofacial Surgeons.