Intra- and inter-examiner reliability of direct facial soft tissue measurements using digital calipers

BackgroundThe objective of this study is to determine if facial soft tissue measurements using digital calipers can be reliably taken by the same examiner and by a large group of examiners.Materials and MethodsTen examiners performed a set of 18 in-clinic measurements on 10 female and 10 male dental students using a digital caliper twice over a 3-week period. The intra-class correlation coefficient and the Shrout-Fleiss method were used for the statistical analysis.ResultsAnthropometric intra-examiner reliability was high for all measurements (none fell below R = 0.934). However, inter-examiner reliability exhibited a wide range of values, some reliable (nasal width at widest nostrils [R = 0.922] and subnasale to upper lip [R = 0.926]), and others unreliable [base of nose (R = 0.590), mouth height (R = 0.585), and soft tissue B point to gnathion (R = 0.623)].ConclusionSoft tissue measurements of clearly identifiable points measured by the same examiner produced highly consistent, accurate and reliable measurements. Soft tissue points with poor definition resulted in average-to-poor reliabilities measurements.