Profile and Frontal Nasolabial Changes Following Le Fort I Maxillary Advancement or Impaction Surgery

Purpose: To determine if there were any measurable differences in nasolabial soft tissue features between surgical-orthodontic patients who received either maxillary advancement or maxillary posterior impaction in the profile and frontal view. Methods: Records for 43 patients consisting of 22 patients for the maxillary advancement group, and 21 patients for the maxillary impaction group were obtained from the archives of the graduate orthodontic program, at the University of Manitoba in Winnipeg, Canada. The profile analysis for nasolabial changes was performed on lateral cephalograms before surgery and post-treatment. Changes in soft and hard tissue landmarks were made on an X-Y axis system centered on Sella Turcica. The four profile nasolabial variables included vertical and horizontal changes in pronasale and labrale superious. The four frontal nasolabial variables included alar base width, nose length, upper lip length, and vermillion display which were measured relative to the patient's intercanthal distance from pre-surgical and post-treatment photos in repose. Results: Maxillary Advancement: The maxillary advancement surgical group had the greatest overall profile and frontal soft tissue changes. All profile variables except vertical height of pronasale showed a statistically significant change (p<0.05). Profile nasolabial changes included forward movement of the nasal tip by 2.5 mm, and forward and upward movement of labrale superious by 3 8 mm and 0.6 mm respectively. All frontal variables except upper lip length showed a statistically significant change (p<0.05). Significant frontal nasolabial changes included widening of the nasal base by 9% (p<0.0001), shortening of the frontal appearance of the nose by 4% (p<0.05), and increase in vermillion display by 19% (p<0.05). Maxillary Posterior Impaction: The maxillary posterior impaction surgical group had the least overall profile and frontal soft tissue changes. All profile and frontal soft tissue nasolabial variables in the maxillary posterior impaction showed no statistically significant changes except alar base which widened by 4% (p<0.05).