Rationale: The etiology of class II division 1 Angle anomaly comprises many entities, including heredity and the vicious habit of sucking the finger. A close connection between the etiology and the clinical features needs to be outlined, in order to have a more appropriate treatment approach.

Aim: This study aims to find common clinical features for two groups of Class II division 1 etiological factors (heredity and the vicious habit of sucking the finger), outlining a characteristic dento-facial pattern for each etiological factor.

Materials and methods: 160 orthodontic cases were studied, taken randomly from the Department of Orthodontics in “Carol Davila” University of Medicine and Pharmacy, between 2005 and 2011. From a total of 46 diagnosed with Class II/1, the following data were noted for each subject in a table: age, sex, etiology, facial symmetry, profile, size of the lower face, stage lip, labiomentonier ditch, menton, form of arches, palate, occlusion in the three plans, Spee curve, other dental anomalies.

Discussions: The facial asymmetry was found in a greater proportion within the finger-sucking group. Subjects in the finger sucking group have 100% pronounced convex profile, with pronounced lip stage and sharp curve of Spee, being known that the thumb-sucking stops the mandible growth and stimulates the upper jaw protrusion.

Conclusions: The predominant etiological factor is heredity and the clinical features obvious for II/1 Angle anomaly are present in the highest proportion in the thumb-sucking group, but no significant differences were observed between the groups studied according to etiology.