Freeway space determination using lateral profile photographs: A pilot study

STATEMENT OF PROBLEM Many methods are reported in literature to determine freeway space (FWS), but they yield dissimilar measurements. PURPOSE Recording FWS of patients during prosthetic rehabilitation is one of the important steps in dentistry. The purpose of this study is to evaluate the ability to predict FWS using lateral profile photographs (LPPs) in edentulous participants. MATERIALS AND METHODS Fifty-three participants in the age range of 20-27 years who met the inclusion criteria were recruited. LPP were taken for all participants using standard protocol and duplicate copy obtained; on which three soft tissue reference points, porion (Stp), gnathion (Stgn), and gonion (Stg) (Stg prenoted on the face) were marked and joined to form an angle Stp-Stg-Stgn. This angle was correlated with the mean FWS obtained using 3 methods, swallowing, phonetics, and no command. Simple linear regression model was used to develop a prediction formula for FWS using Stp-Stg-Stgn angle as the independent variable. RESULTS The angle Stp-Stg-Stgn had a significant negative correlation with FWS (r = -0.76, P < 0.001). Using simple linear regression analysis, the following formula was obtained: FWS (in millimeters) = 11.405 - 0.072 × (Stp-Stg-Stgn angle in degrees). CONCLUSION Within the limitations of this study, considering the usage of LPP as a method to determine the FWS can be recommended.