Determination of vertical dimension of occlusion using lateral profile photographs: A pilot study

PURPOSE: To hypothesize a new theory based on soft tissue reference points on lateral profile photographs (LPPs) for determining the vertical dimension of occlusion (VDO), as there is need to explore for simple strategies. MATERIALS AND METHODS: Fifty-three participants in the age range of 20–27 years who met the inclusion criteria were recruited. LPPs were taken for all participants using standard protocol and duplicate copies obtained, on which five soft tissue reference points, nasion (Stn), subnasale (Stsn), porion (Stp), gnathion (Stgn), and gonion (Stg) (Stg prenoted on the face) were marked and joined to form angles; distance between Stsn and Stgn was considered as VDO in LPP (VDO-LP). The angle formed between Stn-Stsn-Stgn and Stn-Stsn-Stg; Stp-Stg-Stgn and Stp-Stg-Stsn was correlated; two simple linear regression models were developed to predict Stn-Stsn-Stgn and Stp-Stg-Stgn using Stn-Stsn-Stg and Stp-Stg-Stsn as independent variables. Using the formulae, VDO-LP predicted was constructed and correlated with the actual values. RESULTS: The angle Stn-Stsn-Stgn had a statistically significant moderate positive correlation with Stn-Stsn-Stg (r = 0.57, P < 0.001) and angle Stp-Stg-Stgn, a significant strong positive correlation with Stp-Stg-Stsn (r = 0.81, P < 0.001). Using simple linear regression analysis, the following formulae were obtained: Stn-Stsn-Stgn (in degrees) = 0.776 Stn-Stsn-Stg (in degrees) +79.01 and Stp-Stg-Stgn (in degrees) =1.331 Stp-Stg-Stsn (in degrees) +10.2. The predicted and actual VDO-LP values were in strong positive correlation with a coefficient of 0.8. CONCLUSION: With the use of simple landmarks on LPP, it is possible to reconstruct the lost facial dimensions during prosthetic replacement of lost teeth.