Condylar disc relationships and vibration energy in asymptomatic class I 9- to 12-year olds

A proper diagnosis is the key to successful treatment. The purpose of this study was to evaluate the temporomandibular joints (TMJ) by means of lateral and anteroposterior cephalograms, transcranial temporomandibular radiographs, magnetic resonance imaging (MRI), and TMJ electrovibratography (EVG) in asymptomatic and orthodontically untreated Angle Class I subjects. The study sample comprised 31 (13 boys, 18 girls) asymptomatic Class I children with a mean age of 9.7 years. The lateral cephalometric findings revealed that the subjects were mesofacial with an Angle Class I skeletal relationship, and the anteroposterior cephalograms showed a symmetrical craniofacial skeleton. Transcranial TMJ radiographs showed that the TMJs on both sides were symmetrically positioned. The time-frequency distributions of sounds from both right and left TMJs showed a wide range, and the vibrations measured by EVG were considerable. The MRI revealed unilateral disc displacement with reduction in four of the 31 subjects (13%), bilateral disc displacement with reduction in three subjects (10%), and bilateral disc displacement without reduction in one subject (3%). The data confirm that a standardized clinical examination to determine the status of the joint is not an efficient tool. This study suggests that the clinical diagnosis should be supported by extensive TMJ evaluation techniques.