RESUMO
Nasolabial angle is commonly used to assess the soft tissue profile of the subnasal region. The aim of this retrospective study was to evaluate the relationship between the nasolabial angle, the inclination of the lower border of the nose and upper lip, upper incisor inclination and upper lip thickness. A sample of 142 female adolescents aged 13-18 years was chosen. A modified cephalometric analysis was performed with the nasolabial angle, and its components were traced according to Fitzgerald's method. All analysed parameters showed a statistically significant correlation with the nasolabial angle (NLA). The highest correlation was found for the labial (L/FH) and nasal (N/FH) components of the nasolabial angle, respectively. Upper incisor inclinations (1+:SN, U1FA) and upper lip thickness (ULT) had a stronger correlation with L/FH than NLA, but no correlation was found between these parameters and N/FH. Upper lip thickness did not influence the relationship between incisor inclination and NLA or L/FH. The position of the upper incisors and upper lip thickness influence the nasolabial angle indirectly through its labial component (L/FH). Therefore, it seems purposeful to assess the nasolabial angle as a sum of two independent angles, of which only one (L/FH) can be influenced by orthodontic treatment.
RESUMO
Aim: The aim of the study was to evaluate the relationship between nasolabial angle (NLA) with maxillary incisor proclination (U1-NA) and upper lip thickness (ULT). Materials and methods: Pretreatment lateral cephalometric radiographs of 120 patients were taken, and NLA, U1-NA, and basic ULT measurements were obtained for each patient. Descriptive statistics were calculated for all the variables involved in the study. The correlation was found using the Pearson correlation coefficient (r) test. p < 0.01 was considered statistically significant. Results: The mean values of NLA, upper incisor proclination, and ULT were found to be 91.38° ± 7.10°, 34.21° + 5.17°, and 15.38 ± 1.76 mm, respectively. r (r = -0.583) was found between NLA and upper incisor proclination and (r = -0.040) for NLA and ULT. Conclusion: There is a statistically significant relationship between NLA and U1-NA. How to cite this article: Garg H, Khundrakpam D, Saini V, et al. Relationship of Nasolabial Angle with Maxillary Incisor Proclination and Upper Lip Thickness in North Indian Population. Int J Clin Pediatr Dent 2022;15(5):489-492.
RESUMO
OBJECTIVES: To investigate the association between upper lip thickness and the amount of upper lip repositioning upon retraction of maxillary incisors. SETTING AND SAMPLE POPULATION: Pre- and post-treatment lateral cephalograms of 101 patients were reviewed. All subjects were treated with fixed orthodontic appliances including extraction of two maxillary premolars. Only subjects without change in lip thickness between pre- and post-treatment cephalograms were included. MATERIAL AND METHODS: Digital software measurements for lip thickness, pre- and post-treatment upper lip position were performed. Appropriate regression models were developed to explore the correlation between maxillary incisor retraction and lip retraction when controlling for lip thickness and other confounding factors. The level of statistical significance was set at 0.05 for all analyses. RESULTS: A significant correlation was found between change in maxillary incisor position following premolars extraction and change in upper lip position (r = 0.95, P < 0.001). The average ratio between maxillary incisor retraction and upper lip repositioning was 1.43:1. Upper lip thickness was not significantly associated with this ratio (r = 0.003, P > 0.05). CONCLUSION: Although there is a highly significant correlation between maxillary incisor retraction and upper lip repositioning, lip thickness is not significantly associated with the amount of repositioning.