Cephalometric Hard and Soft Tissue Norms in Lebanese Adults

Background Cephalometric norms are commonly used in orthodontic practice and research for guidance in diagnosis and treatment planning. They are related to race and ethnicity, thus making classical norms not applicable to all populations. Objectives The purpose of this study was to: present the cephalometric hard (HT) and soft tissue (ST) norms for adults with well-balanced faces and normal occlusion and evaluate the presence of sexual dimorphism within these measurements. Material and methods The sample consisted of pre-treatment cephalograms of 165 adult Lebanese subjects (59 males and 106 females, with a mean age of 23.6 ± 7.6 years) with balanced profiles and normal occlusion. Selected cephalometric hard and soft tissue measurements were automatically generated using Dolphin Imaging software. Statistical analyses included descriptive statistics for all the measurements and independent samples t-tests to evaluate gender differences. Results Adults with harmonious occlusion and profile exhibited orthognathic jaw relationship and a normodivergent pattern. The inclinations of maxillary and mandibular incisors were comparable to established Caucasian norms. ST facial angle indicated a straight profile in both genders (92.68±2.89 in males and 92.65±3.11 in females), with a nasolabial angle slightly more obtuse compared to Caucasian values (109.03±12.05 in males and 109.15±8.84 in females). Upper and lower lip relationship to E-plane indicated a straight subnasal profile, especially in males. As for gender differences, significantly larger skeletal and soft tissue linear measurements were observed in males (p≤0.05). The major differences resided in thicker and longer upper and lower lips (p≤0.001), more protrusive lips as assessed by lip protrusion and distance to H-line (p≤0.036), and smaller nasofrontal angle and Z-angles (p≤0.036). Conclusions Soft and hard tissue norms in Lebanese adults with pleasant profiles and normal occlusion are comparable to those of Caucasian populations except for jaws that are more retrognathic but smaller in dimensions and a more obtuse nasolabial angle. Gender dimorphism was found in linear skeletal and soft tissue measurements, in addition to larger nasofrontal and Z-angles in Lebanese males.