EMG studies of lip and cheek activity in sucking habits

Pronounced lip and mentalis (perioral) muscle activity was developed during thumb and dummy sucking. Cheek (Buccinator) activity was less evident, showing light to moderate activity. Lip and cheek activity was more noticeable during dummy sucking than thumb sucking. Sucking water through a straw and swallowing produced similar functional patterns to thumb sucking: strong lip and mentalis activity but comparatively low buccinator activity. Activity at rest in perioral muscles was pronounced among thumb and dummy suckers, while buccinator activity was negligible. Lip and cheek activity was substantially less, both at rest and during sucking, in a control group of children who were not thumb suckers.