The pooled SMD indicated a statistically significant decrease in the GCF MMP-8 levels with probiotic supplementation compared to the controls in patients with periodontal disease (SMD = 0.819, 95% CI: 0.417, 1.221, I2 < 0.001, p-value ≤ 0.05, and n = two studies) (Figure 5). Here, MMP8 is linked to periodontal disorder.