Pressure from the lips on the teeth and malocclusion.

The relationship between lip strength and lip pressure (pressure from the lips on the teeth) was studied in 84 children (aged 7 to 16 years) with varying types of malocclusion. The lip strength was recorded with a dynamometer. The lip pressure was measured on the upper and lower central incisors in the rest position, and during chewing and swallowing of crispbread. The lip pressure measurements were made with an extraoral pressure transducer incorporated in a water-filled system with an intraoral mouthpiece. The muscle activity of the lips was recorded electromyographically. Bite and facial morphologies were studied on dental casts and profile cephalograms. There was no correlation between lip strength and lip pressure. Lip strength was lower in children with Angle Class II, Division 1 malocclusion than in children with Class I malocclusion. The lip pressure on the upper incisors, on the other hand, was higher in Class II, Division 1 than in Class I malocclusion, and was lowest in children with Class II, Division 2 malocclusion. The findings suggest that the pressure from the lips on the teeth is a result of the incisor position.

[1]  M. Simpson.  An Electromyographic Investigation of the Perioral Musculature in Class II Division 1 Malocclusion , 1977, British Journal of Orthodontics.

[2]  B. Ingervall,et al.  Application in children of a new method for the measurement of forces from the lips on the teeth. , 1985, European journal of orthodontics.

[3]  D. C. Picton,et al.  A study of pressures exerted by the lips and cheeks on the teeth of subjects with angle's class II division 1, clss II division 2 and class 3 malocclusions compared with those of subjects with normal occlusions. , 1968, Archives of oral biology.

[4]  B. Ingervall,et al.  Effect of oral screen treatment on dentition, lip morphology, and function in children with incompetent lips. , 1985, American journal of orthodontics.

[5]  B. Solow,et al.  A METHOD FOR EPIDEMIOLOGICAL REGISTRATION OF MALOCCLUSION. , 1964, Acta odontologica Scandinavica.

[6]  Anders Lundstrom,et al.  Tooth Size and Occlusion in Twins , 1948 .

[7]  A. L. Posen,et al.  The application of quantitative perioral assessment to orthodontic case analysis and treatment planning. , 1976, The Angle orthodontist.

[8]  A. L. Posen,et al.  The influence of maximum perioral and tongue force on the incisor teeth. , 1972, The Angle orthodontist.

[9]  T. Graber.  Relationship between lip strength and lip function in posture and chewing , 1982 .

[10]  B. Ingervall,et al.  The value of clinical lip strength measurements. , 1981, American journal of orthodontics.

[11]  Johnston Fe,et al.  SKELETAL MATURATION AND CEPHALOFACIAL DEVELOPMENT. , 1965 .

[12]  J. Luffingham.  Lip and cheek pressure exerted upon teeth in three adult groups with different occlusions. , 1969, Archives of oral biology.

[13]  Luffingham Jk.  Pressure exerted on teeth by the lips and cheeks. , 1968 .

[14]  W R Proffit,et al.  Equilibrium theory revisited: factors influencing position of the teeth. , 2009, The Angle orthodontist.