Image distortion of intra-oral photographs: The root coverage model.

AIM: Clinical photographs have been advocated in studies dealing with the quantity of root coverage. Changes in different angles of the camera when taking a photograph may lead to parallax errors resulting in inaccurate measurements. The aim of this study was to explore the distortion of the photographs according to the shooting angle.

METHODS

A dental simulation model with a recession defect on tooth 21 was used. Photographs were taken with a digital camera at 5° intervals between 0° to 35°, by shifting the position of the model. Recession depth and root surface area were calculated with ImageJ and implemented in a mathematical model. The relationship between the experimental measurements and the outcomes of the mathematical model was statistically evaluated. The model was confirmed by clinical data.

RESULTS

When the central axis of the lens of the camera focused on the experimental tooth is within a cone angle ≤36°, the maximum distortion of the recession area ranges from 0% to 14%, the maximum percentage occurring when the angle is coronal to the central axis.

CONCLUSIONS

Photographs without an external device connected to the camera provide a valuable support for root coverage assessment when using ImageJ as a measuring tool.