Table 1.

Characteristics of the smiles used in this study

Adjusted vertical positions of the maxillary central incisors	Gingival margins of the maxillary central incisors	Central to lateral incisor edge level
(1) 0.5 mm intruded	0.5 mm above the canines	0 mm
(2) 0 mm unaltered	Equal with the canines	0.5 mm
(3) 0.5 mm extruded	0.5 mm below the canines	1.0 mm
(4) 1.0 mm extruded	1.0 mm below the canines	1.5 mm
(5) 1.5 mm extruded	1.5 mm below the canines	2.0 mm
(6) 2.0 mm extruded	2.0 mm below the canines	2.5 mm