## 4 Discussion  
When making an orthodontic diagnosis, it is advisable to consider the three main types of records that can be obtained from a patient (photographs, radiographs and study models) to obtain a clearer conceptualization of the initial diagnosis. Different indices have been developed to evaluate the complexity, which is focused on measuring the effort and skill to treat a patient; the main indices used in the orthodontic treatment are the Peer Assessment Rating index (PAR), the Index of Complexity, Outcome and Need (ICON) and the American Board of Orthodontics Discrepancy Index (ABO-DI), which is used in this study [16]. Previous studies have compared the different indices mentioned above with the objective of determining which is more accurate. However, most of these indices were based on a single type of diagnostic record (mainly dental casts) and did not take into account records such as radiographs and photographs [17; 18]. Unlike these investigations mentioned previously, the ABO discrepancy index that was analyzed in this study considered these three elements together to obtain a more objective diagnosis, providing a broader picture of the diagnosis and treatment alternatives. ABO-DI has demonstrated excellent accuracy, even though it has been related in different studies to other factors involved in the orthodontic treatment such as the quality of life, the length of time required for orthodontic treatment and the comparison of results from different orthodontic treatment techniques [19; 20; 21; 22]. In terms of photographs, some authors suggest that they are essential to orthodontic diagnosis and offer advantages such as documentation, treatment acceptance, collaboration and case follow-up [23]. Currently, the indices based on the analysis of photographs can be used to determine the need for orthodontic treatment [24; 25]. [PERSON] et al., 2022 evaluated the agreement between the American Board of Orthodontics Objective Grading System (OGS) and the Peer Assessment Rating (PAR) applied to intraoral photographs and dental casts. A good to excellent inter and intrarater agreement were determined by an ICC, and regarding the ratings on dental casts and photographs, they concluded that the ABO discrepancy index method was more reliable [26]. In our study, interrater and intrarater reliability was also evaluated with an ICC higher than 0.90, which corresponds to an almost perfect agreement according to the Cohen kappa index and Landis and Koch scale. On the other hand, in this study, photographs and scanned digital images allowed to virtually analyze the study models, as well, calculating the discrepancy index, and the results supported the similar diagnostic accuracy of digital images and dental casts. Radiographs are another diagnostic element that has been widely studied, especially in terms of lateral skull imaging, which is used to determine the patient's cephalometrics [27]. [PERSON] et al., 2016 compared the information obtained by using digital cephalometry with that obtained using conventional or manual cephalometric measurements in 50 patients and found that most of the measurements were equally accurate [28]. These results agree with those of this study since the cephalometric measurements obtained through specialized software and those obtained manually did not differ significantly. Regarding the complexity of cases determined with ABO-DI, in our study 57.1% and 57.2% of participants for digital and manual techniques, respectively, had complex to very complex cases, which did not show any statistical difference regarding the different summaries used for measuring the discrepancy index between both techniques. Unlike our results, a recent study reported that 32% of participants had a high complexity case and no statistical differences in the discrepancy index between study groups (girls and boys) were observed [20]. Dental casts are the gold standard for orthodontic diagnosis.