Evaluation of the possible biomarkers that is related to forward movement of the mandibula in class II patients

The purposes of this study are: 1. To investigate the relationship between the cephalometric variables at the end of the treatment and at the start of the treatment and to identify the possible biomarkers that is related to forward movement of the mandibula in Class I and II patients 2. To compare the effects of extraction and nonextraction treatment on mandibular forward movement in Class II patients at pubertal growth support. For this study, the database of Çukurova University, Faculty of Dentistry, Department of Orthodontics was used. Lateral cephalometric radiographs of 276 patients at pubertal growth support (CVM II and CVM III ) at the start of the treatment with Class I and II malocclusion treated with four premolar extraction or without extraction were included. Nonextraction Class II patients were treated with Class II elastics or fixed functional appliances. 1. İncrease in SN-Pog angle was used as the discriminant factor for mandibular forward movement. The patients were divided into two groups according to post-treatment increase in SN-Pog angle Group I (SN-Pog difference ≤1.3°) and Group II (SN-Pog difference >1.3°). ROC analysis was used to assess the relationship between the pre-treatment cephalometric values (FMA, Y, Articular, Gonial angles and Jarabak, Gonial ratios) and mandibular forward movement. 2. İn our study, the patients whom we treated without extraction mechanics compared with the patients whom we treated with extraction mechanics-regardless of the SN-Pog increase. In the Class I malocclusion group, forward movement of the mandibula was similar (according to SN-Pog angle) so all Class I patients were collected as an one group and used as a control group. It was found that: pretreatment cephalometric variables can not be used as a possible biomarker that is related to forward movement of the mandibula. Our hypotesis was not verified. Our study results supports the information that: Class II mechanics do not have a skeletal effect on total mandibular length and mandibular forward movement and their correction is at dentoalveolar level. Also it has been determined that: extraction mechanis are mostly used in patients with vertical growth pattern and in Class II extraction patients mandibula does not move forward with growth.