To: Editor, The Angle Orthodontist
Re: Gidarakou IK, et al. Comparison of Skeletal and Dental Morphology in Asymptomatic Volunteers and Symptomatic Patients with Bilateral Degenerative Joint Disease. Angle Orthod. 2003;73:71–78.
I read with interest the article published in The Angle Orthodontist by Gidarakou et al.1 This is an excellent study demonstrating the possible relationship between degenerative joint disease (DJD) of the temporomandibular joint (TMJ) and skeletal changes within the skull base and the maxillofacial complex. TMJ-related orthodontic research within the last two decades was focused on understanding the relationship between the prevalence of TMJ disk displacement (DD) and DJD in both normal and symptomatic populations and the relationship of DD and DJD to skeletal and morphological changes within the skull base. Although DJD was found in both asymptomatic volunteers and symptomatic patients, many authors reported only casual association and no causality. Gidarakou and coworkers have contributed significantly to the understanding of this interrelationship with this study and have demonstrated compelling evidence that these patients are truly retrognathic.
The results of Gidarakou and colleagues concur with prior studies2 and demonstrate that definitive skeletal changes exist in patients with DD and DJD3,4 and that the mandible actually had a clockwise rotation. Although the 1990 study by Ono5 seemed to confirm the theory that skeletal changes can be brought about by retrognathic jaw positioning, this has never been further demonstrated.
Although the results from ongoing research might prove that retrognathism is acquired and not developmental, what evidence demonstrates causality that DJD is responsible for retrognathism? It is possible that retrognathism may have initially predisposed an individual for disk displacement and then have been further aggravated by etiological factors such as trauma in early childhood or adolescence.
We have known for a long time that radiographic changes of DJD are noticed commonly in young patients presenting with pain and dysfunction6 and that the most important component of the TMJ not visualized on plain films or tomograms for appropriate diagnosis of disk displacements is the disk itself. Because magnetic resonance imaging (MRI) by itself suffices for effective evaluation of both hard tissue and soft tissue components of the TMJ, is it time to replace tomography with MRI for nonemergent preorthodontic assessment of the temporomandibular joints?