Facial heights proportions and occlusal vertical dimension: a cephalometric study

Objectives: The classic techniques that have been used for evaluation of vertical dimension of occlusion (DVO) are phonethics, interocclusal distance and facial tissue contours. None of them has been validated scientifically. The purpose of this study was to validate a cephalometric tool for evaluate the DVO. Methods: A cephalometric study was carried out among 28 females and 20 males aged 23±4, all skeletal class I, with good facial harmony and excellent occlusion. None of the patients had been treated ortodontically. The ratio S-Go/N-Me and the ratio of lower posterior facial height (Ar-Go) to lower anterior facial heigth(ANS-Me) was measured with quix ceph softwear. Data were analysed with linear regression and Pearson's correlation. Results: For the 48 patients we found that Ar-Go/ANS-Me was 0.693 ± 0.095 (mean ± SD), and S-Go/N-Me was 65.577 ± 5.269, applying linear regression analysis we obtained good relationship between this two ratio (r = 0,751), and we think that could be used this equation as predictor since Ar-Go/ANS-Me = -0.191 + 0.013 S-Go/N-Me. Conclusions: The knowledge of the Skeletal class I patients Ar-Go/ANS-Me ratio, may be a useful clinical tool for determine the DVO when it has lost due to severe worn dentition or loss of teeth in patients that previously had good occlusion or apparently has class I. When the DVO has been lost, the knowledge of the ratio for the skeletal class I patient 0.693 ± 0.095 (mean ± SD), and the lower posterior facial height (Ar-Go), that it doesn't change along life, may allow to estimate the best value for the treatment OVD.