MMP8 and periodontitis: During periodontitis, the MMP-8 levels detected in the vestibular periodontal sites (2755.10 pg/mL) were significantly higher than those detected in the palatine (2066.31 pg/mL, p < 0.001), distal (2197.26 pg/mL, p < 0.001), and mesial (2207.06 pg/mL, p < 0.001) sites (Figure 6b).