highly significantp < 0.0001
In RP ( Table 2 ), upper lip thickness demonstrated a highly significant increase of +1.27 mm ( p < 0.0001), while lower lip thickness increased by +1.18 mm ( p = 0.0408).
In RP ( Table 2 ), upper lip thickness demonstrated a highly significant increase of +1.27 mm ( p < 0.0001), while lower lip thickness increased by +1.18 mm ( p = 0.0408).
Although lip thickness values increased slightly in MI, these variations did not reach statistical significance ( p > 0.05), suggesting that lip tension improves primarily during functional mandibular support rather than static positioning.
In MI, the nasolabial angle also showed a decreasing trend (−2.59°), but the difference did not reach statistical significance ( p = 0.2629), likely due to greater inter-individual variability under functional mandibular engagement.