Inferior Sclera Exposure and Maxillary Sagittal Position: Is there any Relationship?

Background: Maxillofacial hard and soft tissues play an essential role in the formation of facial aesthetics. The aim of this study was to determine the relationship between inferior scleral exposure and maxillary sagittal position. Methods: The present study was performed on the lateral cephalometric radiographs and frontal facial photographs of ۱۱۰ adolescent subjects. The participants were divided into two equal groups according to gender (۵۵ subjects per group). Total eye height and inferior scleral heights were defined, and scleral exposure ratios were calculated on facial photographs. The measurements were performed for right and left eyes, and the mean value for inferior scleral exposure ratio was calculated. Soft and hard tissue measurements of maxilla were performed on lateral cephalometric radiographs. Independent t test, Mann-Whitney U test, and Pearson correlation test were used to analyze the data. Results: There was no statistical difference between genders in the inferior scleral exposure ratio, NPerp_A, A’_True Vertical Line (TVL), and Upper Lip_TVL parameters (P>۰.۰۵). However, maxillary height was greater in male subjects than females (P<۰.۰۰۱). The inferior scleral exposure ratio was statistically significantly correlated with NPerp_A distance in males (r=۰.۲۸۶; P<۰.۰۵). However, there was no correlation between other maxillary parameters and inferior scleral exposure ratio in males (P>۰.۰۵). The inferior scleral exposure ratio was significantly correlated with maxillary height in females (r=-۰.۲۹۶; P<۰.۰۵). However, there was no correlation between other maxillary parameters and inferior scleral exposure ratio in females (P>۰.۰۵). Conclusions: While the inferior scleral exposure ratio was correlated with NPerp_A distance in male adolescents, the inferior scleral exposure ratio was correlated with maxillary height in female adolescents.