We would like to thank Dr Muralidhar Mupparapu for his kind comments concerning our recent paper, “Comparison of Skeletal and Dental Morphology in Asymptomatic Volunteers and Symptomatic Patients with Bilateral Degenerative Joint Disease” (Angle Orthod. 2003;73:71–78). We hope these data contribute to the scientific literature.
We would like to make a few comments. Though there is a clockwise rotation of the mandible, this does not imply that this produces a distal condyle position. In fact, studies that have evaluated disk displacement and condyle position show that there is not a one-to-one relationship with the presence of disk displacement. Subjects with normal disk position, in general, have 35% with anterior position, 40% with concentric position, and 25% with distal position. When there is disk displacement, 22% will be anterior, 33% will be concentric, and about 45% will be distal.1 In general, there is about a 20% shift to the distal. Though these data are significant, one can see by the distributions that there is not a one-to-one relationship.
Dr Mupparapu suggests that trauma in early childhood may be a risk factor for the development of disk displacement/TMD. Though there is an increased prevalence of trauma in symptomatic patients compared with controls, there is only a 20% increase in the symptomatic patients.2 Because disk displacement, with or without pain, is common in children and young adults,3,4 it is hard to make the correlation with confidence that trauma “caused” disk displacement. There are no data evaluating the relationship.
We would applaud the suggestion that tomography does not give enough information to warrant its use on every patient. We would also like to suggest that even though magnetic resonance imaging (MRI) is an excellent tool for the evaluation of the temporomandibular joint, the diagnosis of an asymptomatic patient with disk displacement should not change the normal, customary care given to a patient presenting for orthodontics, prosthodontics, or other restorative dentistry. To date, there is no study that suggests we can predictably prevent or correct disk displacement with splint therapy or restorative dentistry. Protrusive splint treatment, validated with MRI, does not always maintain disk position.5 There are also no studies that suggest that we should be changing condyle position.
We would like thank Dr Mupparapu for his kind comments and The Angle Orthodontist for publishing this paper.
