Effects of Class II Correctors and Functional Appliances on the Periodontal Health of the Mandibular Incisors – a Prospective Cone-Beam Computed Tomography (CBCT) Study

The purpose of this investigation was to evaluate the effects of Class II correctors and functional appliances on the dentoalveolar support of the mandibular incisors during orthodontic treatment. Twenty six patients who were treated with a ForsusTM, Herbst, or MARA participated this study. Lateral cephalometric radiographs, limited field-of-view CBCTs, and periodontal measurements were collected both the day of appliance activation and day of appliance deactivation. Ten hard tissue measurements on all four mandibular incisors were collected at each time point on CBCT images. Bone thickness increased at 6 and 9 mm apical from the cementoenamel junction (CEJ) on the buccal (p=0.0005 and p=0.0003, respectively) and 3 and 6 mm apical from the CEJ on the lingual (p=0.0031 and p=0.021, respectively) during treatment. No significant changes to the vertical height of buccal (p=0.2622) or lingual (p=0.1145) bone occurred during treatment. Locations and magnitudes of hard tissue changes suggest that a combination of uncontrolled tipping of the incisors and dentoalveolar bending occurs during Class II correction with these appliances. Soft tissue outcomes were difficult to ascertain, and may be related to uncontrollable hygiene variables. This study suggests that appropriate use of these appliances does not cause negative clinical or radiographic sequelae in the short-term