Objectives: To test the hypotheses that the Damon system will maintain intercanine, interpremolar, and intermolar widths. To test subsequent hypotheses that the Damon system will not produce a significant difference in maxillary and mandibular incisor position/angulation when compared with control groups treated with conventional fixed orthodontic appliances for similar malocclusion.
Materials and methods: Subjects treated with the Damon system (N = 27) were compared with subjects treated with a conventionally ligated edgewise bracket system (N = 16). Subjects' pretreatment and posttreatment lateral cephalometric radiographs and dental models were scanned, measured, and compared to see whether significant differences exist between time points and between the two groups.
Results: Results did not support the claimed lip bumper effect of the Damon system and showed similar patterns of crowding alleviation, including transverse expansion and incisor advancement, in both groups, regardless of the bracket system used.
Conclusions: Maxillary and mandibular intercanine, interpremolar, and intermolar widths increased significantly after treatment with the Damon system. The mandibular incisors were significantly advanced and proclined after treatment with the Damon system, contradicting the lip bumper theory of Damon. Posttreatment incisor inclinations did not differ significantly between the Damon group and the control group. Patients treated with the Damon system completed treatment on average 2 months faster than patients treated with a conventionally ligated standard edgewise bracket system.