A periodontitis case should be defined using the staging and grading system proposed in the 2018 Classification of Periodontal and Peri-Implant Diseases and Conditions (Caton et al., 2018;Tonetti et al., 2018). Accurate and consistent case definitions are critically important, as they can have an impact in estimating the prevalence of periodontitis (Stødle et al., 2021), in assessing the actual need for periodontal therapy (Herrera et al., 2022;Sanz, Herrera, et al., 2020), in the definition of the periodontal prognosis (Saleh et al., 2022;Takedachi et al., 2022) and may influence the results and associations presented in the studies (Deng et al., 2021;Goergen et al., 2021).The consistency and accuracy among periodontal experts, general dentists and undergraduate dental students in defining periodontitis cases using the staging and grading system were first evaluated by Marini et al. (2021). It was showed that intra-rater agreement was almost perfect, whilst inter-rater agreement was moderate. In addition, the definition of stage was more accurate