Submentovertex radiology: cephalometric considerations in temporomandibular dysfunction

Controversy exists in the literature concerning the association between the radiographic and the clinical features of the temporomandibular dysfunction (TMD). Hence, this study reinvestigated possible correlations between radiographically detected asymmetries and the clinical signs and symptoms of TMD. Complete clinical and radiographic records were gathered from 52 patients sequentially referred for corrected angle tomographs of the temporomandibular joint (TMJ). Measurements from submentovertex (SMV), lateral and posterior-anterior (PA) cephalographs and corrected angle parasagittal tomographs and recorded clinical signs and symptoms of TMD were the data inputs. Significant findings were as follows: a) as the discrepancy in the posterior condyle to pogonion measurement increased, the pogonion and both maxillary and mandibular incisors shifted laterally towards the shorter side; b) as the ANB angle increased, so did the difference in condylar angle measurements between the two condyles; c) the side with the larger condylar angle was positioned forward on the SMV; and d) a perpendicular bisector (Marmary's Centerline) of the line drawn between the right and left foramen spinosum was found to be a reliable baseline reference for SMV analyses. No statistically significant relation was found linking specific signs and symptoms of TMD to maxillofacial asymmetries recorded on SMV, lateral or PA cephalographs. None of the radiographic signs studied were found to be good predictors of specific signs and symptoms in TMD.