Evaluation of soft tissue compensation in normodivergent skeletal class 2 cases

Aim: The aim of this study was to evaluate the facial soft tissue compensations related to the position of maxilla and mandible with reference to the anterior cranial base in normodivergent skeletal Class 2 patients. Material and methods: 3 groups were formed according to the pre-orthodontic cephalometric films of 240 subjects (120 male, 120 female) with normodivergent growth pattern (SN-GoGn 32°±5°) and 14-16 years of age were divided into three groups based on ANB angle; Group 1: Skeletal Class 1 (ANB 2°±2°, SNA 82°±2°, SNB 80°±2°), Group 2: Skeletal Class 2, protrusive maxillary (ANB˃4°, SNA˃84°, SNB 80°±2°), Group 3: Skeletal Class 2, retrusive mandible (ANB˃4°, SNB˂78°, SNA 82°±2°). Males and females were evaluated separately and each group include 40 cases. Possible differences between groups and sexes were assessed in 10 thickness values, 2 anguler measurements, 1 soft and hard tissue angle ratio. The reliability and repeatability of the measurement methods in this study was performed using paired samples t-test and ANOVA. The measurement systems used were reliable and reproducible, statistical analysis of the data was performed using paired samples t-test and ANOVA. Results: When the measurements of soft tissue thicknesses, angles and angle ratios between groups were evaluated in male cases, the values of Pr-Lsp, Pog-Pogˈ (p˂0,05) and Id-Lip, Me-Meˈ (p˂0,001) in Group 1 and 2; , the values of B-Bˈ, Pog-Pogˈ, MLA (p˂0,005) and Id-Lip, Me-Meˈ (p˂0,001) in Group 1 and 3; the values of A-Aˈ, N-A-Pog/ Nˈ-Sn-Pogˈ (p˂0,05) in Group 2 and 3 were found to display significant differences. When the measurements of soft tissue thicknesses, angles and angle ratios between groups were evaluated in female cases, the values of Pog-Pogˈ, Me-Meˈ (p˂0,05), A-Aˈ (p˂0,005) and Pr-Lsp, Id-Lip, MLA (p˂0,001) in Group 1 and 2; the values of B-Bˈ (p˂0,005) and Id-Lip, Pog-Pogˈ, Me-Meˈ, MLA in Group 1 and 3; the values of Id-Lip (p˂0,05) in Group 2 and 3 were found to display significant differences. There were a significant differences in Ac-Pn (Group 1 ve 2 p˂0,05; Group 3 p˂0,001), A-Aˈ, Pr-Lsp, and Id-Lip (p˂0,001) parameters in all groups when sexual dimorphism was evaluated in measurements of soft tissue thickness, angle and angle ratio in different groups. Also, significant difference were observed in Group 1 concerning MLA (p˂0.05); in Group 2 concerning Me-Meˈ (p˂0.05), Glb-Glbˈ (p˂0,001); In Group 3 related to B-Bˈ (p˂0,05) and N-A-Pog / Nˈ-Sn-Pogˈ (p˂0,001) parameters. Conclusion: In normodivergent skeletal Class 2 cases, soft tissue compensation is associated with the position of the jaws in relation to the anterior cranial base in various regions of the face. Keywords: Skeletal Class 2, soft tissue, compensation.