Effects of Myofunctional Therapy with an Oral Screen on Lip Length and Strength in Clll Division 1 Patients

The most common muscular disorder of ClII division l malocclusion is hypofunction of the upper lip and hyperfunction of the lower lip at rest and function. Myofunctional therapy with oral screens can be applied in such patientsto improve the size and function of the lips. This study aimed at evaluating how myofunctional therapy with an oralscreen affects the strength of the lips and their morphology.
Materials & Thirty-five patients with Cl II division 1 malocclusion were included in the present study but at the end of the study two subjects were excluded due to lack of compliance. The remaining 33 subjectswere assigned to 3 groups: group 1 (n = 12), cooperative patients; group 2 (n = 6), patients with poor cooperation; and group 3 (n = 15), the controls. All the three groups underwent treatment with functional appliances; lip training was carried out for 5.5 months, 3 times a day for 10 minutes each time in the treatment group. Before and after the treatment the lip strength was recorded with the use of a custom-made dynamometer and lip morphology was studied on lateral cephalograms. The parametric paired t-test was used to compare values within the groups and independent t-test was used to compare changes between the groups. Statistical significance was set at p value The lengths of the upper and lower lips increased significantly (p value = 0.00) and interlabial gap decreased significantly in group 1 (p value = 0.00). However, in the control group and group 2 only theinterlabial gap decreased significantly (p value = 0.00 and p value = 0.01). The thickness of the upper lip in region A' in group 1 was significantly (p value = 0.02) higher than that in the control group after treatment. The strength of the lips increased significantly in all the groups but it was greater in groups 1 and 2.
Under the limitations of the present study, it appears myofunctional therapy with an oralscreen improved the function and morphology of the lips when it was performed regularly.