Effect of unilateral mastication on TMJ disc position and clinical symptom

Objective: To investigate the effect of unilateral mastication on TMJ disc position and symptom. Methods:Sixty 26 to 35-year-old patients(30 male and 30 female,) with unilateral mastication habits in our department were recruited during the period from December 2012 to December 2013. Clinical examination and MRI examination on both sides of TMJ with bite and open positions were performed. Results: Of all the 120 TMJs, there were no significant differences between working and non-working sides(P0.05) for disc reversible advancement(13 and 10), disc irreversible advancement(11 and 14), joint effusion(15 and 12) and clicking(7 and 9), respectively. There were significant differences between working and non-working sides(P0.05) for disc inwards movement(4 and 13), disc outwards movement(12 and 3), respectively. Conclusion: Unilateral mastication shows certain effects on TMJ disc inwards and outwards movements but no effect on disc reversible, irreversible advancement, joint effusion and clicking.