Mandibular fossa

Abstract: Articular cartilage can proliferate sufficiently to alter the contours of joints, allowing them to adapt morphologically to various mechanical stresses This remodeling has been classified into three types based on histologic criteria which were then applied to the temporomandibular joint This joint has a fibrous type of articular tissue which is converted postnatally into fibrocartilage in the loaded areas The thickness and cell population of this tissue, and the amount of internal reconstruction in the subchondral bone vary from one part of the joint to another These changes appear related to the distribution of mechanical stresses in the joint Conclusions drawn are: The temporomandibular joint shows the following remodeling trends: progressive remodeling on the anterior part of the condyle, medial part of the tubercle, and roof of the mandibular fossa; regressive remodeling on the posterior part of the condyle and on the lateral part of the tubercle A perforation in the disc causes progressive remodeling on the condyle and regressive remodeling on the tubercle at the perforation site Articular remodeling merges gradually into osteoarthritis as the articular tissue breaks down The net effect of remodeling that has become uncompensated or pathologic is: condyle flattened and enlarged, tubercle resorbed, disc perforated, and articular surfaces uneven If the dentition is not restored or replaced, a high rate of temporomandibular remodeling occurs which will probably continue into osteoarthritis

Abstract: Objective The purpose of this study was to evaluate temporomandibular joint morphology and to compare possible structural variations in the temporomandibular joint anatomy of symptomatic anterior disk displacement patients with possible structural variations in the temporomandibular joint anatomy of symptom-free volunteers Study design Fifty-six symptomatic patients and 25 symptom-free volunteers were included in this study All subjects had bilateral high-resolution magnetic resonance imaging scans performed in the sagittal (closed and open) positions Disk positions were evaluated with these images, and the patients were accordingly classified into 4 diagnostic groups The angulation between the Frankfort horizontal plane and the posterior slope of the articular eminence, as well as the width and depth of the glenoid fossa and the articular tuberculum, were automatically measured with the aid of a computer Results The Mann-Whitney U test demonstrated significant differences in the angular and linear values obtained in disk displacement with reduction patients in comparison with the values obtained in patients with disk displacement without reduction and in symptom-free volunteers Conclusion It is proposed that a steeper posterior slope and higher tuberculum articulaire are predisposing factors for the development of disk displacement with reduction Flattening of the eminence may progress in time, leading to the onset of disk displacement without reduction (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;92:98-107)