Investigating Measurements From Dental Photographs

Abstract

INTRODUCTION The demand for dental care has increased dramatically in the last few years, which has put dental hospitals and dental practices under considerable pressure in securing dental appointments for patients. High demand means more people seeking dental appointments everyday which has detrimental impact on the environment. Dental photographs taken by patients remotely may reduce the demand for in person appointments, but to be used in orthodontic screening and monitoring, accurate measurements are required.

AIM To determine whether measurements obtained from photographs can be a valuable alternative for the gold standard clinical measurements.

METHODS An estimation of the upper central incisor mesiodistal width was recorded using a caliper on a plastic skull measured three times, which gave a value of 9.5 mm to act as a baseline reference. Photographs of the skull were captured from five different angles: zero-degree, 5° vertical, 10° vertical, 5° horizontal, and 10° horizontal from a distance of 24 cm. These photos were then uploaded to a computer software Adobe® Photoshop® 2024. 10 postgraduate orthodontic students measured the tooth on the computer screen from each angle (T0), then the procedure repeated after 4 weeks (T1) yielding a set of 100 measurements.

RESULTS The average measurement taken of the upper central incisor from the photograph taken with a 10° horizontal discrepancy provided the closest measurement to the reference value. However, the measurements taken from this photograph also showed the highest variation between the raters (inter-rater variability) and between the measurements taken at the two timepoints (intra-rater variability). Generally, the results showed high variation amongst the rater’s measurements both at an inter-rater and an intra-rater level. The photograph taken at zero degrees demonstrated the least inter- and intra-variation, but the width of the tooth was underestimated by 0.82mm (average). I believe these results reflect the fact that photos at zero degrees are free from any distortion and hence yield constant measurements.

CONCLUSION Taking measurements from photographs can be an alternative option to clinical measurements. However, measurements from these photographs will be associated with an error. Overall, measurements from photographs taken at zero degrees, free from any distortion, are likely to give more reproducible measurements, but these measurements are likely to underestimate the width of the upper central incisor. Repeating the measurements from the photos improved the precision. Therefore, repeating the measurements more than one time is a viable procedure to yield measurements closer to the clinical ones.