Evaluation of accuracy and reliability of space analysis by simple visual observation in the permanent Dentition

Abstract

Space analysis is a fundamental part of orthodontic diagnosis and treatment planning, especially when deciding about whether or not extracting some teeth in order to gain space to solve TSALD. Though there are so many methods described for space analysis, most clinicians prefer to just observe the study model, and then estimate the amount of crowding or spacing based on their own experience. Despite the frequent use of Simple Visual observation (SVO), few studies have investigated SVO as a diagnosis method. Therefore, it seemed appropriate to design a study to measure the accuracy and reliability of space analysis by SVO in the permanent dentition. Methods and Materials 52 dental records of patients with TSALD were selected randomly and then 5 orthodontists were asked to estimate the amount of spacing or crowding by SVO. They were also asked to repeat the procedure for the same dental casts two weeks later. The intra-rater and inter-rater reliability was calculated. True amount of crowding was measured by assessing the digital models and then the results were compared to those estimated by the raters. Results The amount of ICC for inter-observer reliability was 9.765 and 9.577 for intra-observer reliability, which is an almost perfect agreement. The validity (mean error of the difference between the actual amount of TSALD and the estimated numbers) was 1.3 millimeters. Conclusion Regarding the high inter-observer and intra-observer reliability, SVO seems to be a very reliable method for space analysis. An error of 1.3 millimeters shows we can easily count on SVO as an almost accurate method. Nevertheless, measuring the validity of SVO is not as definite as determining its reliability. Since we do not have a gold standard for measuring the spacing or crowding, we recommend future studies to be done to determine factors affecting the validity of SVO and actually a gold standard for space analysis.