To compare three-dimensional (3D) ClinCheck™ models with the subjects' actual 3D posttreatment models using the American Board of Orthodontics Objective Grading System (OGS).This prospective, within-subject study included 27 consecutive cases treated with aligner therapy. The posttreatment plaster models taken immediately after treatment were scanned and converted to stereolithography (STL) files; the ClinCheck models were also converted to STL format. MeshLab software was used to measure the seven components of the OGS, including alignment, marginal ridges, buccolingual inclinations, occlusal contacts, occlusal relationships, overjet and interproximal contacts. An overall OGS deduction score was also calculated.Compared with the posttreatment models, the ClinCheck models showed significantly (P = .016) fewer overall OGS point deductions (24 vs 15). These overall differences were due to significantly (P < .05) more deductions among the posttreatment models than the ClinCheck models for alignment (4.0 vs 1.0 deductions), buccolingual inclinations (4.0 vs 3.0 deductions), occlusal contacts (3.0 vs 2.0 deductions), and occlusal relations (4.0 vs 2.0 deductions).The ClinCheck models do not accurately reflect the patients' final occlusion, as measured by the OGS, at the end of active treatment.