Scleral exposure changes after Le Fort I maxillary advancement with vertical component in individuals with skeletal Class III malocclusion-A stereophotogrammetric image study.

Objective: This retrospective study aimed to evaluate inferior scleral exposure changes in Class III patients that underwent orthognathic surgery with Le Fort I osteotomy with and without vertical displacement.

Materials And Methods: Preoperative and 6 months postoperative cephalograms and stereophotogrammetric images of 45 subjects (mean age: 21.66 ± 2.97 years) who underwent orthognathic surgery for Class III correction were retrieved. Subjects were divided into 3 groups: maxillary advancement-only (AO), maxillary advancement + impaction (AI) and maxillary advancement + downfracture (AD). Exclusion criteria were mandibular-only surgery, occlusal canting, facial asymmetry, orbital surgery and craniofacial syndrome. One investigator measured inferior scleral exposure on both sides using following landmarks: upper eyelid margin (A), inferior limbus (B) and lower eyelid margin (C). Distance between A and C was recorded as overall eye height (E), and distance between B and C was recorded as inferior sclera exposure (S). S:E ratio in percentage was calculated to standardize sclera exposure relative to overall eye height. Wilcoxon signed-rank and Kruskal-Wallis tests were used for statistical analysis (P < .05).

Results: Mean value of maxillary movements was as follows: 4.21 ± 1.82 mm advancement in AO, 5.08 ± 2.18 mm advancement and 2.33 ± 0.99 mm impaction in AI, 3.95 ± 1.45 mm advancement and 3.1 ± 0.71 mm downfracture in AD. Change in reduction of scleral exposure was significant in all groups (P < .05). AI group bilaterally and AO group right side had highest differences (-4.96 ± 4.86, -6.09 ± 4.21, -4.99 ± 3.23, respectively). There was no significant difference between groups in S:E ratio changes (P > .05).

Conclusion: Intergroup comparisons showed no statistically significant difference, revealing similar reduction in all three groups despite the differences in the vertical movement variable.