Abstract: PURPOSE: To investigate the effect of buccolingual inclination and width of molars and their alveolar ridge height in skeletal Class III patients with width discrepancy by camouflaged treatment using cone-beam CT (CBCT). METHODS: Sixteen adult patients (5 males, 11 females) with mild to moderate skeletal Class III were treated with camouflaged method in the Department of Orthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University from 2014 to 2015. CBCT scans were performed before and after treatment. Dicom data were calibrated and reconstructed using the software Simplant 16.0. Fifty-nine landmarks and two reference planes were located and measured in three coordinated dimensions. The data was processed using SPSS 17.0 software package. RESULTS: The buccolingual inclination of the maxillary first and second molars were increased, while the mandibular ones were decreased significantly after treatment (P<0.05). The inter-molar width was increased in the upper arch while decreased in the lower arch. The buccal alveolar ridge height of maxillary molars was decreased significantly (P<0.05). No significant difference of alveolar ridge height was found in the lingual side of maxillary molars or either side of mandibular molars. CONCLUSIONS: Camouflaged treatment deteriorated the transverse compensation in skeletal Class Ⅲ patients with width discrepancy, accompanied with maxillary buccal alveolar bone resorption. When camouflaged treatment is planned, the potential of molar compensation in transverse dimension should be clearly defined. Appropriate pre-adjusted appliance or surgery- assisted expansion should be considered to avoid periodontal risks.

Key words: Skeletal Class Ⅲ malocclusion, Camouflaged orthodontic treatment, Transverse compensation, Alveolar ridge height