Serial measurements of facial asymmetry using a wooden tongue depressor in patients with congenital microtia

Background and objectives: Congenital microtia may be associated with hemifacial microsomia, but little is known about their correlation and development with aging. Historically, facial asymmetry is easily assessed by observing the occlusal cant using a tongue depressor. We serially measured the occlusal cant in children with microtia to evaluate change in facial asymmetry with growth.

Methods: Since 2011, frontal photographs of patients with congenital microtia biting a tongue depressor were obtained and reviewed. The occlusal angle was compared between the baseline and final photographs, and the change was compared between cant-positive (>3° at baseline) and cant-negative (<3° at baseline) groups. Multivariate analysis was conducted to determine variables associated with the change in occlusal angle.

Results: Overall, 105 patients were enrolled. With a mean age of 5.4 years at baseline and a mean follow-up of 3.9 years, clinically significant aggravation was observed in 15.4% and 24.2% of cant-positive and cant-negative patients, respectively. Hemifacial microsomia (OR, 4.825; p = 0.005) and occlusal angle at baseline (OR, 0.821; p = 0.045) were associated with aggravation, but the severity of microtia showed no significant association.

Conclusions: When hemifacial microsomia was present, the occlusal cant seemed to be aggravated in children with microtia at later ages. When the occlusal cant was present without noticeable hemifacial microsomia, some compensation in facial asymmetry was expected. The use of a wooden tongue depressor is a simple, non-invasive, and radiologic hazard-free aid to detect notable change in facial asymmetry in children with microtia.