MMP8 and periodontal disorder: Furthermore, increased salivary levels of inflammatory protein biomarkers such as interleukin-1β (IL-1β), IL-6 and matrix metalloproteinase-8 (MMP-8) have been described to be associated with periodontal disease status (Kinney et al., 2011; Ebersole et al., 2013; Rathnayake et al., 2013; Ebersole et al., 2015).