[Correlation between vertical hard and soft tissue variables of the face]

Facial vertical variables are important components of soft tissue analysis which are used in clinical esthetic evaluation. The purpose of this study was to evaluate the correlation between vertical skeletal and dental variables of hard and soft tissues of human face. A total of 46 patients [23 boys and girls] were included in this cross-sectional study. Selected angles and facial dimensions were measured during the clinical appointments. For facial proportions, from frontal view, selected reference points were marked on the face. The accuracy of this work was validated by an orthodontist. Hard tissue variables were also measured using patients' lateral cephalograms. Finally, the correlations between soft and hard tissue variables were evaluated using correlation and regression analysis. The statistical analysis showed correlations between number of vertical soft and hard tissue variables, with linear relationship among some of them. Significant correlation was detected between nasolabial angle of soft tissue and hard tissue N-Pog, N-B, N-A, N-Me and Lower incisor to Mandibular plane [P=0.014, P=0.013, P=0.046, P=0.015, P=0.037 respectively]. Also, significant correlation was detected between soft tissue N-Me and hard tissue N-Me, and N-Pog; between soft tissue supraorbital ridge to subnasal and hard tissue N-A, and between soft tissue subnasal to menton and hard tissue A-Me and A-B [P=0.000 in all cases]. The highest correlation was observed between soft tissue subnasal to menton and hard tissue A-Me [R=0.738]. Given the results of this study, it can be concluded that some clinical parameters in vertical dimension, of facial hard tissue variables can be replaced by soft tissue counterparts in order to design the diagnosis and treatment plan according to soft tissue variable measurements

correlation of smile line with the vertical cephalometric parameters of anterior facial height

In the evolution of orthodontics, the changes in soft tissue, especially smile line attracts considerable attention. The present study was carried out to evaluate the correlation of the smile line with the vertical parameters of anterior part of face. Forty-six Iranian adults, aged between 18-25 years were selected. Five quantitative and three qualitative variables of smile analysis were recorded for each subject. Cephalometric analysis was carried out using angular and linear parameters. The correlations between smile line variables and cephalometric parameters were calculated using Spearman and Pearson's correlation analyses. The result of this study showed that the cephalometric parameters of N-Me, Pn-Line, N-B, N-Pg had significant correlations with quantitative variable of tooth-lower lip position. The P-values were P=0.003, P=0.027, P=0.006, P=0.002 respectively. N-Me, N-B, N-Pg represented significant correlations with interlabial gap on smile [P= 0.006, P=0.036, P=0.002 respectively]. There was a significant correlation between N-Pg and quantitative factor of tooth-upper lip position [P=0.034]. Upper incisor to palatal plane showed a significant correlation with qualitative variable of tooth-upper lip position [P=0.019], interlabial gap on smile [P=0.004], and tooth-upper lip position [P=0.006]. Upper incisor to FH represented a reverse relation with incisal edge to lower lip [P=0.028].This parameter also showed significant correlations with quantitative factors of tooth-lower lip position [P=0.040] and crown height [P=0.002]. According to the results of this study, it can be concluded that, linear skeletal and dental vertical factors affect the vertical features of smile. Angular vertical parameters, except gonial angle, influence the vertical position of smile