Investigation of the Relationship between Sagittal Skeletal Nasal Profile Morphology and Malocclusions: A Lateral Cephalometric Film Study

The aim of this study was to evaluate the relationship between skeletal sagittal nasal profile morphology and sagittal skeletal malocclusions. Regarding lateral cephalometric films, the study was conducted in a total of 135 individuals without any prior orthodontic treatment (mean age of 17.91 ± 1.91), including 49 males (mean age 17.91 ± 1.16) and 86 females (mean age 17.78 ± 1.91 years). The groups were divided into two groups as male and female according to gender, and three groups as skeletal Class 1, Class 2, and Class 3 according to the Steiner's ANB angle. In addition, skeletal groups were compared within groups by dividing into two groups of male and female. A total of eight parameters, three skeletal sagittal angular (SNA, SNB, and ANB angles), four nasal linear (R-A, N-A, N-ANS, and N-R distances) and one nasal angular (N1-N2/N2-R angle), were measured on each cephalometric film. The arithmetic mean and standard deviation of all measured nasal parameters were calculated. For statistical analysis, independent sample t-test and one-way analysis of variance (One-Way ANOVA) were used for normally distributed data, and Mann Whitney U and Kruskal Wallis tests were used for data that did not show normal distribution. For statistical analysis, p < 0.05 was considered significant. R-A, N-A, and N-ANS linear nasal parameters differed significantly between the male and female groups, which were evaluated regardless of the skeletal groups, with a higher rate in males (p < 0.05). N-R linear nasal parameter showed a statistically significant difference between skeletal malocclusion groups, which were evaluated regardless of gender. N-R distance was found to be significantly longer in skeletal Class 3 individuals than in Class 1 and 2 individuals (p < 0.05). There was no statistically significant difference in nasal bone concavity angle in all groups (p > 0.05). R-A and N-A linear nasal parameters showed statistically significant differences between male and female sex groups in all skeletal malocclusion classes (p < 0.05). At first, results showed that males had longer measurements than females in all linear nasal parameters. Second, longer measurements were found in all linear nasal parameters in skeletal Class 3 individuals than those in skeletal Class 1 and Class 2 individuals. Third, the nasal bone concavity angle was greater in skeletal Class 2 individuals than the others.