Effect of the tongue-in-groove technique on the smile form.

There are different qualitative and quantitative methods used to evaluate the smiling form, including the length and angles of the side view of the face (1). Among the clinical factors used to estimate the esthetics of the smile, the Maxillary Incisor Show (MIS), is defined as "the vertical distance between the caudal upper lip in the midline and at the caudal-most aspect of the maxillary central incisors".