Lip Mobility

When a patient smiles, the upper lip will elevate and display the maxillary incisors. Symmetry of movement in this case allows for uniform display and is considered esthetic.23 Mean lip mobility results in a reduction of 80% of the original lip length and a subsequent display of maxillary anterior teeth of approximately 10mm with a natural smile.23 Physiologic lip mobility ranges from 2-12mm, but considerable heterogeneity is present among individuals.26 Lip mobility is greater in women compared to men and women are more likely to have excessive lip mobility.23 Such excessive lip mobility may cause excessive gingival display during full smile despite normal lip length (Figure 6).

Figure 6: Excessive gingival display related to lip mobility during full smile.
ce649 - Fig6