Using computed tomography, photogrammetry & structured light scanning for measuring human mandibles: a comparison of metric analysis using various 3D imaging technologies

This paper aims to determine if photogrammetry and/or structured light scanning (SLS) can be used as alternatives for conducting metric assessments on mandibles as opposed to computed tomography (CT). Identifying alternative imaging options to CT is important as, although CT is accurate and reliable, there are multiple limitations that impact its accessibility, including cost, portability, and ease of learning. Photogrammetry and SLS are two handheld, lightweight, cost-effective alternatives that are relatively user friendly. Therefore, this paper imaged 33 human mandibles using CT, photogrammetry, and SLS. For intra-observer error, the ICC results were between 0.37 and 1, indicating a range of unreliable to excellent measurements. Almost all TEM results were within the acceptable threshold set for this study (< 2). Despite graphical demonstrations of the measurements being provided to the observers, all inter-observer results were unreliable, indicating that further refinement of these definitions is required before a protocol can be developed. However, all inter-modality assessments were within the acceptable threshold (< 5 TEM). The range for the ICC results for CT v photogrammetry was between 0.37 and 0.88. For CT v SLS, the results were between 0.47 and 0.87. Overall, photogrammetry had the highest degree of consistency with CT, but all methods proved to be interchangeable. This paper highlights that alternative imaging options are available in scenarios where CT cannot be accessed.