Cheek and lip pressure against maxillary dental arch during dummy sucking.

The sucking pattern and intra-oral negative air pressure were studied simultaneously with the cheek/lip pressure in 12 children when sucking a dummy. The cheek/lip pressure was measured at the canine and at the second primary molar on the right side of the upper dental arch. The cheek/lip pressure peaks followed the intra-oral negative air sucking pressure peaks continuously. In the canine region the mean value of maximum cheek/lip pressure was 54 g/cm2. The corresponding value at the second primary molar was 21 g/cm2. During dummy sucking the mean cheek/lip pressure was 3.4 times higher against the canine compared to the second molar (P less than 0.001). The intra-oral negative air pressure was approximately the same whether the cheek/lip pressure was measured at the canine or at the second primary molar. The results indicated that the circumoral muscles were especially active during dummy sucking, in addition to the cheek pressure in the canine region.