During the orthodontic treatment, the RANKL/OPG ratio did not vary when compared with the ratio detected at the post-periodontitis examination; however, this RANKL/OPG ratio was lower at all the analyzed time-points when compared with the RANKL/OPG ratio detected during periodontitis: 1 week (ratio 3.14, p < 0.001), 1 month (ratio 3.06, p < 0.001), 3 months (ratio 3.20, p < 0.001), 6 months (ratio 2.44, p = 0.004), 12 months (ratio 2.15, p = 0.001), 18 months (ratio 2.53, p < 0.001), and 24 months (ratio 2.34, p = 0.001) (Figure 3a). The gene discussed is TNFRSF11B; the disease is periodontitis.