All ETDs from UAB

Advisory Committee Chair

Chung H Kau

Advisory Committee Members

Nada Souccar

Luther T Cale

Christos Vlachos

Amjad Javed

Rama K Chavali

Document Type


Date of Award


Degree Name by School

Master of Dentistry (MDent) School of Dentistry


The objective of the present study was to grade the overjet of untreated plaster dental study casts with optimal occlusion utilizing the American Board of Orthodontics (ABO) Objective Grading System (OGS). Currently no data set exists for incisor contact norms in optimal occlusion. Materials and Methods: 140 Plaster dental study casts possessing optimal occlusion were utilized for this study. Study casts used were obtained from the office of Dr. Lawrence F. Andrews in San Diego, CA. The majority of the study models were those used in determining Andrews Six Keys to Normal Occlusion. Overjet was graded according to the ABO OGS with each incisor being given a grade of 0, 1, or 2 for a total of 8 point deductions possible per pair of study casts. Results: Only 4 of the 140 (3%) study casts measured received no point deductions, implying that all incisors were in contact. 123 study casts (88%) had all incisors within 1mm of contact. 528 incisors (94%) out of the total sample of 560 were also within 1mm of contact. Conclusion: Currently the goal for overjet in cases brought before the American Board of Orthodontics is to have all incisors in contact. The results of the study suggest that the overwhelming majority of optimally occluding non orthodontically treated patients do not have their incisors touching, but are within 1mm of contact. The data acquired in this study can be used when determining final treatment goals for incisor contact.

Included in

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