Effects of lip-closing training on maximum voluntary lip-closing force during lip pursing in healthy young adults.

To investigate the effect of lip-closing training, the time-course of multidirectional lip-closing forces during training was evaluated. The subjects were healthy young adults with no systemic disease. Ten subjects each were allocated to the training and non-training (control) groups.

Relationship between frontal craniofacial morphology and horizontal balance of lip-closing forces during lip pursing.

The objectives of this study were to quantitatively evaluate the relationship between frontal craniofacial morphology and the horizontal balance of the lip-closing forces (LCF) generated during maximum voluntary pursing-like movements in patients with mandibular deviation. Thirty-one subjects (median age 25·4 ± 8·9 years) without a history of orthodontic treatment were randomly selected from among the orthodontic patients who visited our hospital. Lip-closing forces was recorded in eight directions during maximum voluntary pursing-like lip-closing movements.