One of the most popular contributions of Dr. Joseph Jarabak to Orthodontics was the Jarabak analysis (1972) which showed the effects of dentofacial growth to pre and post orthodontic treatment outcomes. Jarabak’s cephalometric analysis, based on the Björk study with modifications from Steiner, Tweed and Ricketts, has been used to determine the characteristics of facial skeletal growth. Jarabak’s cephalometric analysis mainly considers the vertical interrelation using the cranial base as reference. The study can be divided into skeletal and dental components. Evaluating the components of this analysis would give a better understanding of the growth pattern and the corresponding facial profile. Jarabak analysis included: the saddle angle (N.S.Ar), articular angle (S.Ar.Go), gonial angle (Ar.Go.Me), anterior facial height (N-Me), and posterior facial height (S-Go). Additionally, the facial convexity angle (G´.Sn.Pog´) was measured to determine the type of profile. Dr. Jarabak concluded a facial height ratio of less than 60% for clockwise growth type, 62-65% for a straight downward growth type and greater than 65% for a counterclockwise growth type. Dividing the gonial angle into upper and lower compartments aids in determining the morphology of the ramus and body of the mandible.
Dr. Ronald H. Roth, trained under Dr. Joseph Jarabak at the Loyola University School of Dentistry in Chicago, further studied and modified Jarabak’s Cephalometric analysis and concluded a modification of facial height ratio of 54-58% for clockwise growth type, 59-63% for neutral growth type and 64-80% for counterclockwise growth type. In contrast to the original Jarabak analysis, the Roth-Jarabak analysis uses the Downs A-point instead of the A-point that is set at 2 mm in front of the apex of the middle maxillary incisor.