## 2 Materials and Methods  
After receiving the approval of the Tel-Aviv University Ethics Committee, 100 cephalometric radiographs were collected from radiography centers and 50 of those radiographs were of patients with normal facial structures (Class-I = Orthognathic) and the other 50 radiographs were of patients with specific skeletal deformities as radiographed before their orthodontic preparation before surgery began. Radiograph inclusion criteria were as follows (Relative Class-III = Prognathic): lack of previous orthodontic treatment and the absence of syndromes, including Cleft Palate. The cases selected were in the age range of 20-30, characteristic of the age of Ortho-Surgery patients. All personal data were erased from the radiographs by the experimenter. Subsequently, two lines signifying the Frankfort Horizontal Plane and the Inferior Border of the Mandibular Plane, as well as reference points (B) point, (A) point, and (N) Nasion, were drawn on all 100 radiographs (Figure 2). The severity of the deformity was calculated according to Steiner's Analysis as the angle between points A and B and Point N [13]. Next, the researcher provided the 100 radiographs in random order (not according to the skeletal diagnosis of the patient) to each of the participants. Demonstration and instruction were provided to all participating physicians, after which each participant marked the longitudinal axis of the upper incisor (U1) relative to the Frankfort Horizontal Plane (FH) and the longitudinal axis of the lower incisor (L1) relative to the Inferior Border of the Mandibular Plane (MP) on all 100 radiographs.  
After all the above-mentioned marked presentations were obtained, the following angles were calculated respective to the different markings:  
1. U1 TO FRANKFUT PLANE;
2. L1 TO MADIBULAR PLANE;
3. U1 TO NA;
4. L1 TO NB;
5. ANB.  
Angle calculation was performed using the Cephnija(r) angle calculation application, and the results were gathered and maintained in a separate table for each participant. After all angle results were collected, they were statistically analyzed with SPSS(r)IBM software to calculate the average Standard Error in each measurement among the different examiners (SE). (Table 1) Next, a statistical analysis (\(t\)-test) and Bonferroni correction for multiple comparisons between the Class-I patient group (Orthognathic) and the Class-III patient group (Prognathic) were performed:  
U1 TO FRANKFUT PLANE (Class-III versus Class-I);  
L1 TO MADIBULAR PLANE (Class-III versus Class-I);  
U1 TO NA (Class-III versus Class-I);  
L1 TO NB (Class-III versus Class-I).  
[PERSON]'s correlation was conducted between ANB versus STD results in each one of the groups.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Angles Degree** & & & & & & & & \\
**and SD** & **U1 TO FH-** & **SE-U1 TO FH** & **L1 TO MP-** & **SE-L1 TO MP** & **U1 TO NA-** & **SE-U1 TO NA** & **L1 TO NB-** & **SE-L1 TO NB** & **ANB** \\
**CLASSES** & & & & & & & & \\ \hline
**CL-I** & 120.432\({}^{\circ}\) & 9.008 & 96.072\({}^{\circ}\) & & & & & \\
**CL-III** & 119.286\({}^{\circ}\) & 12.177 & 69.149\({}^{\circ}\) & 11.585 & 30.446\({}^{\circ}\) & 15.4407 & 33.47315\({}^{\circ}\) & 9.439 & \(-\)2.8392\({}^{\circ}\) \\ \hline  & & & & & & & & \\  & & & & & & & & \\  & & & & & & & & \\ \end{tabular}
\end{table}
Table 1: Summary of average data of examinations performed (in parentheses: minimum and maximum data range).