For example, in Group B, for periodontitis patients treated with egg white-derived cystatin, the mean inhibition rate was 80.10% ± 5.89%, while in Group C periodontitis patients treated with low-molecular-weight cystatin achieved a mean inhibition rate of 83.08% ± 6.63%, with inhibition rates ranging from 71.89% to 94.33%. This evidence concerns the gene CST4 and periodontitis.