Related Experiment Video
Updated: Sep 23, 2025

Measuring the Complete-arch Distortion of an Optical Dental Impression
Published on: May 30, 2019
Evaluation of the distortion of photographs using various focal lengths
Nilesh Suresh1, Arvind Sivakumar1
1Department of Orthodontics and Dentofacial Orthopaedics, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India.
Abstract:
It is of interest to evaluate the distortion of intraoral frontal photographs using various focal lengths. Intra-oral frontal view pictures of 20 subjects were taken using a standard 18-55mm lens of a DSLR camera at three different focal lengths (18mm, 35mm, 55mm). 52 experienced orthodontists were chosen and they were asked to assess the photographs and choose the one with the least amount of distortion. Majority of the orthodontists selected the frontal photograph taken at a focal length of 35mm as the best photo with the least distortion among the three photographs. The photos taken at a focal length of 35 mm showed the least amount of distortion.
Related Concept Videos
Focusing of Light in the Eye
Distance Corrections
Common Leveling Mistakes and Errors
Influence of Earth's Curvature and Atmospheric Refraction on Leveling
Design Example: Measuring Distance Between Two Points with Obstructions

