The divisions of Angle's Class I malocclusion were described by Martin Dewey, who classified Class I malocclusion into several subtypes based on specific dental irregularities such as crowding, spacing, and rotations. This detailed subdivision helps in diagnosing and planning precise orthodontic treatment. Dewey's classification refines Angle's original concept by addressing the variations within Class I malocclusion rather than only focusing on molar relationships. This makes Dewey's work clinically valuable for identifying different treatment needs within the same molar classification.

Reference: Graber’s Orthodontics, 7th Edition.