The Study Of The Bone Density Changes Around Teeth During Orthodontic Treatment Between Different Periodontal Biotype

Objective:To observe the maxillary alveolar bone density changes in patients with mild-to-moderate chronic periodontal disease at alignment and leveling arch stage.To discuss the differences of alveolar bone density changes comparing with different periodontal biotypes before and after orthodontic treatment,providing reference for clinical practice.Methods:20 cases of adult female patients were selected randomly and were divided into the periodontal health group (group A) and the periodontal disease group (group B) in accordance with the periodontal status, with 10 cases in each group, respectively. Then the patients were further divided into the labial-moving thin gingival group AI1 and group BI1, thick gingival group AⅡ1 and BⅡ1, as well as palatal-moving thin gingival group AⅠ2 and group BI2, and thick gingival group AⅡ2 and group BⅡ2 according to various periodontal biotypes and tooth moving direction. Group A received conventional orthodontic treatment, while group B received combined periodontal orthodontic treatment; shot the CBCT before orthodontic treatment (TO) as well as 8 months after the leveling and aligning stage (T1), in addition, the changes of alveolar bone density in the 20 patients before and after orthodontics were measured. SPSS22.0 statistical software was applied in analyzing all detection indexes.Results:① Before and after the leveling and aligning of orthodontic treatment,the decrease in alveolar bone density was more distinct in the periodontal disease group than in the periodontal health group,which mainly occurred in the neck of tooth(P<0.05). The alveolar bone absorption ratio in the periodontal disease group was neck of tooth root>middle of tooth root>apex of tooth root (P<0.05). ② Comparison within the periodontal health group, the bone density changes between different tooth movement and periodontal biotype were of no statistical difference (P>0.05).③ Comparison within the periodontal disease group,the alveolar bone density in labial-moving was dominated by decrease, and the decrease rates had notable difference between thin and thick biotype in the palatal-side of the middle of tooth root and the labial-side of the apex of tooth root (P<0.05); and the decrease rates between group BI2 and group BⅡ2 were of no statistical significance (P>0.05).④ Comparison between the periodontal health group and the periodontal disease group, the alveolar bone absorption in the labial-side of the neck and middle of tooth root, as well as the palatal-side of the apex of tooth root in group BI1 was more than that in group AI1, with the difference being statistically significant (P<0.05); in group AI2 and group BI2, the bone density in the labial-palatal side of the neck of tooth root was higher in group B than in group A, with the difference being statistically significant (P<0.05). ⑤Comparison between the periodontal health group and the periodontal disease group,the alveolar bone absorption in the labial-side of the neck of tooth root, as well as the palatal-side of the middle and apex of the tooth root was higher in the BⅡ1 group than in the AⅡ1 group, and the difference was of statistical significance (P<0.05); and in group AII2 and group BⅡ2the alveolar bone absorption in the labial-side of the middle of tooth root was higher in the periodontitis group than the periodontal health group, and the difference was of statistical significance (P<0.05).Conclusions:①The alveolar bone density was greatly changed in both the periodontal health group and the periodontal disease group before and after the leveling and aligning of orthodontic treatment, which were dominated by decrease; the alveolar bone absorption ratio in the periodontal disease group was neck of tooth root greater than middle of tooth root,greater than apex of tooth root. ②Between different periodontal biotype,the alveolar bone absorption in the labial-moving of the periodontal disease group was higher than that in palatal-moving. ③Comparison between the periodontal health group and the periodontal disease group,the alveolar bone density changes in the labial-moving as well as the palatal-moving was higher in the periodontal disease group than in the periodontal health group.