Delatola C, et al. – Based on pre–treatment radiographic and microbiological characteristics, the researchers intended to identify phenotypes of periodontitis patients by the use of an unsupervised modeling technique (clustering). This retrospective study suggested that untreated periodontitis patients can be clustered into at least three phenotypes on basis of alveolar bone loss patterns and microbiological data. These outcomes should be validated in other cohorts and the clinical utility needs to be explored on the basis of periodontal treatment results and/or disease progression.