Scleral exposure alterations following Le Fort I osteotomy (with and without maxillary impaction) in skeletal class III patients: A before-and-after clinical trial.

PURPOSE: Exposure of sclera below the iris in natural head positions is aesthetically undesirable. Studies on post-surgical changes in inferior scleral exposure following orthognathic surgery are scarce and mostly retrospective. The aim of this clinical trial is to examine the effect of Le Fort I osteotomy, a procedure for correction of malocclusion and maxillo-mandibular deformities, on the inferior scleral exposure and overall scleral surface area in skeletal class III patients. MATERIALS AND METHODS: This trial was performed on 40 eyes of 20 skeletal class III patients undergoing Le Fort I osteotomy without impaction (n = 20 eyes) and with impaction (n = 20 eyes). Standard true-size frontal photography was performed pre-operatively and post-operatively at 6 months. After measuring the overall eye height and the height of visible inferior sclera, the ratio of inferior sclera to overall eye height (S:E) was calculated three times. Also, overall surface area of the sclera was measured three times. The average of three attempts was considered the main measurement. Changes in the sclera after the surgery and between both methods were compared. RESULTS: The average age of patients (9 men, 11 women) was 24.5 years. Age and gender were balanced between the two groups (P > 0.05). S:E ratios decreased in both groups after surgery (P < 0.05, Wilcoxon test). The decrease was greater in the impaction group (P < 0.05, Mann-Whitney test). Similar results were observed for overall sclera surface areas. CONCLUSION: Maxillary advancement, with or without impaction, reduced the inferior scleral exposure and overall scleral surface area. The effect was more pronounced in the impaction group.