Another clinical study by Taalab and colleagues revealed the striking role of local use of TTO 5% gel in the enhancement of periodontitis-related clinical parameters, including pocket depth, gingival, bleeding, and clinical attachment indices, and reduction of levels of MMP-8 (Figure 2), the main cause of the destruction of type I, II and III collagen, which in turn results in the reduction of disease severity (Taalab et al., 2021 ▶). Here, MMP8 is linked to periodontitis.