Abstract
The purpose of this study was to investigate the effects of frenulum labii superioris on lip closure by measuring the position of the frenulum labii superioris, the lip closing force, the upper lip pressure, the lower lip pressure and the upper-lower lip pressure ratio. Data were obtained from 259 patients (119 boys and 140 girls) ranging from 4 to 18 years of age. The subjects were classified into five groups based on of their ages. The results were as follows:
1. For all five groups, a significant statistical positive correlation was observed between the position of the frenulum labii superior and the lip closing force.
2. For all five groups, no significant statistical correlation was observed between the poison of the frenulum labii superior and the upper and lip pressure or the lower. A significant statistical positive correlation was observed, however, between the frenulum labii superior and the upper-lower lip pressure ratio.
3. A significant statistical correlation among all five groups showed no significant difference.
These results suggest that the high position of the frenulum labii superior inh ibits lip closure in children.
