Hall technique crowns and children's masseter muscle activity: A surface electromyography pilot study

Abstract

Abstract Background Hall technique crowns (HTCs) alter the occlusion temporarily, potentially affecting jaw muscles, particularly the masseter – the primary jaw‐closing muscle. Aim To assess masseter muscle activity (MMA) in children treated with a unilateral HTC. Design In 12 children treated with a single HTC, bilateral MMA was recorded with surface electromyography (sEMG) for ten cycles of Rest Position (RP) and Maximum Voluntary Clenching (MVC) over 20 seconds immediately pre‐HTC cementation (P base ), immediately post‐HTC cementation (P immed ), at 2 weeks post‐HTC cementation (P 2w ) and at 6 weeks post‐HTC cementation (P 6w ). t test, ANOVA and post hoc statistics were used ( P < .05). Results As expected, MMA was low at rest and increased during maximal jaw clenching ( P < .0001). MMA (mean ± SD) increased significantly ( P < .001) between RP and MVC at: P base [from 1.60 μV·s (±0.96) to 5.40(±2.30)]; P immed [1.57(±1.15) to 3.75(±1.87)]; P 2w [1.39(±0.54) to 5.54(±1.45)] and finally P 6w [1.46(±0.56) to 6.45(±2.56)]. Rest MMA at P base , P immed , P 2w and P 6w remained unchanged ( P = .18) whereas P base clench MMA reduced by a third at P immed ( P < .001), returned to and exceeded baseline levels at P 2w ( P = .822) and P 6w ( P < .001), respectively. Conclusions This pilot study showed that Hall technique crowns may affect masseter muscle activity in children. Clench MMA was reduced immediately post‐treatment but returned to and later exceeded baseline levels at 2 and 6 weeks, respectively. Rest MMA remained unchanged.