Periodontal parameters and cervical root resorption after orthodontic tooth movement

Objectives: To assess the relationship between periodontal parameters and cervical root resorption in orthodontically moved teeth. Methods: In a standardized experimental tooth movement in 16 periodontally healthy subjects, 29 premolars were tipped bucally by applying a force of 1 N during 8 weeks. 19 contralateral premolars not subjected to orthodontic tooth movement served as controls. Plaque Index (PlI), Gingival Index (GI), probing depth and bleeding on probing were assessed 3 times before and 6 times during the experimental phase. Teeth were extracted and scanned in a micro-CT scanner with a resolution of 9 μm. The presence or absence, and the severity of cervical root resorption were evaluated on the 3D reconstruction of the scans by two calibrated examiners. Results: Over-all, periodontal parameters were not different between the test and the control teeth. Clear signs of buccal cervical resorption were detected on 27 of 29 orthodontically moved teeth and on 1 control tooth. 10 subjects had a perfect oral hygiene and no gingivitis, whereas 6 subjects showed a moderate level of plaque and gingivitis (>20% occurrences of PlI or GI with >0). However, no relationship could be demonstrated between resorption and the periodontal parameters. Conclusion: Nearly all orthodontically moved teeth showed signs of cervical resorption. Periodontal parameters were unrelated to this important side effect of orthodontic treatment. Supported by the Swiss National Science Foundation (Grant No. 3200B0-112296).