Ideal Overjet Research Articles

In a retrospective study, 90 American Board of Orthodontic (ABO) cases were evaluated for treatment outcome. Changes in occlusion, cephalometric skeletal and dental variables, soft tissue variables, and root resorption were evaluated. The occlusions of completed ABO cases were compared with 147 naturally occurring good-to-excellent occlusions from the Andrews Foundation for Education and Research, using the Ideal Tooth Relationship Index (ITRI). Cephalometric variables were evaluated in relation to an "acceptable range" based on established standards. Photographs were evaluated for lip posture at rest and at closure, and the incidence and the severity of root resorption of maxillary and mandibular teeth excluding second molars were evaluated from panoramic radiographs. After treatment, occlusions of ABO cases scored significantly higher overall and for all ITRI segments except the anterior interarch segment when compared with Andrew's sample. In all the ABO cases, ideal overjet and overbite were attained. Cephalometrically, the mandibular plane and the Y-axis angle showed no significant change as a result of treatment. However, skeletal dysplasia (ANB) and skeletal convexity (Na-A-Po) showed improvement. Dentally, the maxillary incisor position and inclination, the interincisal angle, and the lower incisor position ended within the acceptable range, whereas the lower incisors were proclined. Soft tissue variables also improved, lip balance and harmony, closure at rest, and closure without strain all improved. The nasolabial angle showed little change. Most of the root resorption was minor in nature and involved the maxillary and mandibular central and lateral incisors. In conclusion, the ABO cases were well treated and showed marked improvement in occlusion, cephalometric, and soft tissue changes, although experiencing minor iatrogenic effects.

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