Pacific Coast Society of Orthodontists Bulletin Summer 2012 - (Page 13)

Condylysis By David C. Hatcher, DDS, MSc., MRCD(c) Edited by Dr. Ib Leth Nielsen, DDS, Clinical Professor Emeritus, Program Director, Division of Orthodontics, Univ. of California, San Francisco a new technology in radiographic imaging, is now available in many orthodontic offices. This technology provides better diagnostic capabilities than have ever been available. However, with greater technology comes increased responsibility to make accurate diagnoses of any existing pathologies in every patient. With this also comes a need for better education in the area of dental radiology. At UCSF, we are very fortunate to now have our own dental radiologist, Dr. David Hatcher, on the faculty, where he teaches our residents proper techniques for systematically analyzing their 3-D images from CBCT. Such analysis ensures that any pathology or abnormality in dental development is diagnosed, and nothing important is missed. In this issue of Faculty Files, Dr. Hatcher addresses condylysis, which typically affects young, growing women and can be a challenging task for the clinician. CBCT, Synonyms Condylysis is also known by the terms idiopathic condylar resorption (ICR), osteoarthritis (OA), degenerative joint disease (DJD), arthrosis deformans and progressive condylar resorption (PCR). Definition Condylysis is a localized non-inflammatory degenerative disorder of the TMJ that is characterized by lysis and repair of the articular fibrocartilage and underlying subchondral bone; it occurs around the time of puberty in females.1 Background and Etiology The current theories include a combination of chemical transduction and mechanotransduction. The basic concept is that lysis of the hard and soft tissues occurs when adaptive capacity has been exceeded by functional demands. Chemical and mechanotransduction can play a role in reducing and exceeding the adaptive capacity threshold.2-8 Elevated or reduced serum levels of beta-estradiol and elevated serum levels of relaxin are thought to be significant.2 Elevated serum beta-estradiol and relaxin, separately and together, have been shown to have a negative effect on the TMJ disc. Serum beta-estradiol has an osteo-protective effect in enhancing osteoprotegenin (OPG) expression and decreasing osteoclast activity. Therefore, reduced estrogen may predispose to a bone-degenerative process. Clinically, most cases of condylysis are preceded by a disc displacement, so theories that consider soft tissue changes are attractive. Mechanotransduction, or single-cell biomechanics, is the study of how physical forces influence biologic processes. Single-cell biomechanics depend on their material properties relative to the surrounding matrix. TMJ disc cells are a heterogeneous mixture of fibroblasts and fibrochondrocytes. The TMJ disc is a fibrocartilagenous tissue, but it is not a homogeneous tissue. The disc is composed mostly of collagen (type I), proteoglycans (glycosaminoglycan chains that are primarily chondrotin sulfate and dermatan sulfate) and water. The distribution and arrangement of the disc components are not uniform. The disc is divided into SuMMeR 2012 • PCSO Bulletin 13

Table of Contents for the Digital Edition of Pacific Coast Society of Orthodontists Bulletin Summer 2012

President's Message
Executive Director's Letter
PCSO Business
AAOF Report
PCSO at a Glance
Practice Management Diary
Faculty Files
Correction to Faculty Files article, Spring 2012
Seasoned Practicioner's Corner
Case Report Pre-Treatment
Portrait of a Professional
From Good to Great in a Tough Economy
Three-Dimensional Volumetric Imaging: An Emerging Diagnostic Tool
Destination Success
Case Report Post-Treatment
Earl's Pearls

Pacific Coast Society of Orthodontists Bulletin Summer 2012