# An Evaluation of the Ramus Mandibular Asymmetry on the Panoramic Radiography
## 2 Materials and Methods  
The study group was selected from the population of Bucharest and its surrounding areas, consisting of 214 patients (134 females and 80 males; age range: 7-15 years) with malocclusions who need orthodontic treatment. The patients included in the study were divided into five groups of malocclusions: four groups according to Angle classification: Class I, Class II/1, II/2 and Class III, to which was added the fifth group, patients with unilateral posterior crossbite (UPC), a category in which patients who had at least one pair of teeth with posterior crossbite, were included. The groups were organized as follows: 21 subjects, Class I (9.8%); 56 subjects, Class II/1 (26.2%); 55 subjects, Class II/2 (25.7%); 35 subjects, Class III (16.4%); and 47 subjects with unilateral posterior crossbite UPC (22%). The criteria for inclusion in the study group allowed for the participation of patients who presented with first molar teeth on the mandibular arch, aged between 7 and 15 years of both genders and with no history of orthodontic treatments. Patients whose panoramic radiographs had poor resolution or had horizontal distortions, patients who showed signs of craniofacial syndromes or malformations and major temporomandibular joint disorders were excluded from the study group. For each patient, before beginning orthodontic treatment, the initial panoramic radiography was analyzed for diagnostic purposes. Informed consent was obtained from the relatives of all patients before the start of the study. Ethical approval was given by the Research Ethics Committee. In this study, the panoramic radiographs were made in the same center, using the same Planmeca ProMax panoramic device (Planmeca Oy, 00880 Helsinki, Finland), in accordance with the manufacturer's instructions (66 kVp, 7 mA, and 16 s), in a standard manner. The X-rays were taken with the patient's incisors in an edge-to-edge relationship in a pipe. Pre- orthodontic treatment panoramic radiographs were checked for imaging quality, the visibility of mandibular condyles, and the absence of radiographical artifacts projecting over the mandibular structures. The evaluation was conducted in a dimly lit room with tonal adjustments made to the images to improve the view, as conducted by a single investigator. The panoramic X-rays were traced manually using acetate paper and a hard lead pencil (2H) on an X-ray view box (Huion(r)). A maximum number of 10 random radiographs were analyzed during each working session in order to prevent investigator fatigue. The maximum mesiodial widths of the mandibular first molar teeth were assessed bilaterally to detect horizontal distortion. To avoid it, panoramic radiographs with mesiodistal size differences greater than 1 mm between the right and left mandibular first molars were excluded from the study. On the panoramic radiography, the vertical parameters of condyle height (CH), ramus height (RH), and total height (CH+RH) were measured on the right and left side, and the indices of mandibular asymmetry were calculated according to the Habets et al. method, as shown in Figure 1.  
The points and lines on the panoramic radiography for calculating the asymmetry index were as follows:  
* O1: the most lateral point of the condyle on the panoramic radiography;
* O2: the most lateral point of the ascending ramus on the panoramic radiography;
* A line: the line tangent to the mandibular ramus, drawn between point O1 and point O2;  
Figure 1: Linear measurements according to the Habets et al. method [32]. O1 si O2 the most lateral points corresponding to the vertical ramus; A line, tangent to the vertical ramus; B line, from the most superior point of the condyle perpendicular to the A line; CH: condyle height; RH: ramus height; CH+RH: total height of mandibular vertical ramus. From the Mann-Whitney U test in Angle Class III malocclusions, the highest difference between females and males was observed between females (3.0%) and males (2.4%), with the \(p\)-value being 0.15 and without any significant differences.