Lip posture and mouth width in children with unilateral cleft lip.

The aim of this study was to measure on photographs the protrusion of the upper and lower lips and demonstrate their relationships to each other, to measure the width of the mouth, and to compare these findings within complete and incomplete cleft groups and with normal controls at the ages of 5 and 10 years. It was found that the lower lip was more protrusive and the mouth width was narrower in 5-year-old children with complete clefts prior to maxillary collapse than in the control children. It is concluded that there is a lack of tissue in the cleft lip leading to less distensibility and increased lip pressure and that this may be one of the factors causing maxillary retrusion.