[Extraction treatment on orthodontic patients with Stage IV/Grade C periodontitis: a preliminary study].

Objective: To evaluate the effect of extraction treatment on orthodontic patients with Stage Ⅳ/Grade C periodontitis. Methods: Eight orthodontic patients with Stage Ⅳ/Grade C periodontitis (3 males, 5 females, 25~38 years old) who had finished extraction treatment during January 2003 and December 2013 were included in the study. The patients accepted periodontal treatment and extraction orthodontic treatment in the Department of Periodontology and Department of Orthodontics at Peking University School and Hospital of Stomatology. Clinical examination records and periapical films of 34 teeth adjacent to extraction sites (TAES) and 34 teeth non-adjacent to extraction sites (TNES) were evaluated and compared. Probing depth (PD) and relative bone height (RBH) before and after orthodontic treatment were also compared. Results: No significant difference was found between PD of TAES and that of TNES (P>0.05). After orthodontic treatment, RBH of TAES was increased by 8.19% (-3.36%,14.01%) (P<0.05). RBH of TAES far from extraction sites was elevated by 7.73% (-1.52%, 21.55%)(P<0.05). Tooth resorption rate of TAES was 13.1% (1.3%, 23.9%)and TNES was 4.3% (-8.19%, 12.5%) after orthodontic treatment, and the difference was statistically significant. Conclusions: Under proper combined periodontal and orthodontic treatment, stability of periodontal status in patients with Stage Ⅳ/Grade C periodontitis can be maintained. Relative bone height of extraction sites can be elevated after orthodontic treatment.