A visually pleasing chin is an important component of facial harmony.
This study was undertaken to introduce a practical classification of c
hin dysmorphology, which can be used to guide the surgeon toward the a
ppropriate surgical approach to chin repair. Analysis of life-size pho
tography, based on standard anthropometric measurements, was completed
on 2,879 patients from 1981 to 1991. Six hundred eighty-four patients
were noted to have normal occlusion with some form of chin deformity.
Analysis of this group of patients identified seven categories of chi
n dysmorphism: Class I, macrogenia (n = 170, 24.9%); Class II, microge
nia (n = 435, 63.6%); Class III, combination of macrogenia in one dire
ction and microgenia in the other direction (n = 54, 7.9%); Class IV,
asymmetry (n = 4, 0.6%); Class V, soft tissue ptosis (''witch's chin''
) (n = 13, 1.9%); Class VI, pseudomacrogenia (normal skeletal symphysi
s mend with excess soft tissue covering) (n = 5, 0.73%); and Class VII
, pseudomicrogenia (long-face deformity producing clockwise rotation o
f the normal mandible) (n = 3, 0.4%). Having diagnosed the dysmorphism
, logical surgical recommendations for lower face improvement were pos
tulated. Only patients with Class II chin deformity can be corrected w
ith augmentation. Classes I, III, and IV require an osteotomy of the c
hin. Classes V and VI benefit from soft tissue correction. Class VII d
eformity can be corrected with a maxillary osteotomy.