Effects of previous orthodontic therapy on periodontal status of patients in long-term supportive periodontal care

Background While many German children and young adults receive orthodontic treatment, the number of patients requiring periodontal treatment is increasing due to demographic changes. Investigating the long-term effects of orthodontic treatment on periodontal health, particularly in patients developing periodontitis, is therefore of public health interest. Methods Sixty periodontitis patients with ≥ 10 years of SPC received digital intraoral scans during cross-sectional SPC follow-up examination (T1). Patients’ previous orthodontic treatment (POT) or no treatment (NOT) was recorded. The Index of Orthodontic Treatment Need (IOTN) at T1 was assessed. Dental and periodontal parameters were recorded and compared with retrospective data from ten years earlier (T0). The association between changes in clinical attachment levels (CAL T0-T1) and treatment group (POT/NOT) was analysed (multiple linear regression). Spearman correlations between IOTN and clinical parameters were assessed. Results The change in parameters from T0 to T1 was as follows (POT: n = 24 patients, NOT: n = 36 patients): Mean tooth loss: 0.92 ± 1.74 vs. 0.64 ± 0.90; Mean probing pocket depth: -0.03 ± 0.33mm vs. 0.05 ± 0.51mm; Mean CAL: 0.11 ± 0.59mm vs. 0.09 ± 0.66mm. No association was found between CAL change and treatment group. Only a negligible correlation between IOTN and changes in dental, periodontal, and oral hygiene parameters was found. Conclusions Patients with successfully treated periodontitis, both with and without a history of orthodontic therapy, show a high level of periodontal stability during long-term SPC and comparable orthodontic conditions. Trial Registration: Clinical trial registration number on the German clinical trials register: DRKS00011316.