Iranian Journal of Orthodontics
Volume:7 Issue: 1, Mar 2012

The form of the facial skeleton and dental relationship is race specific, and estimating the cephalometric standards in each race is important. The purpose of this study was to determine the McNamara''s Analysis standards in Iranian population and to compare them in Iranian men and women. In this Cross Sectional study cephalograms of 75 Iranian adults (18-35yrs) including 36 males and 39 females that represented Class I skeletal relationship, normal vertical pattern and space deficiency less than 3 mm were selected Eleven indexes of McNamara Analysis were manually traced and analyzed. Mann-Whitney and Independent t-tests were used to compare values between males and females. It was shown that there is significant difference in effective length of mid face, mandibular length and lower onethird height between men and women (p<0.05).Our study findings was very similar to McNamara`s norms Despite the larger jaw dimensions in Caucasian compared to Iranian ethnic group. McNamara analysis can be applied for Iranian population.

One of the most important reasons appealing orthodontic treatment or orthosurgery is the tendency to improve the face beauty. Since the main influence of orthodontic treatment is on the profile region particularly on the lower face therefore we focused chin. The aim of this study was to compare the perception of attractiveness among orthodontist, surgeon and lay people in case of vertical & horizontal changes in silhouette profile of chin. In the present research, we chose two standard profile pictures (a man and a woman) from reliable resources. Each picture have been changed to silhouette using Photoshop CS2 program. Then we changed the chin position in vertical and horizontal dimensions for 2mm incrementally. The range of changes in vertical dimension for man’s picture was between -6 to +6 and for women was between -4 to +4. Also in horizontal dimension, the range of changes in man’s pictures was from -10 to +10 and for woman’s picture was between -8 to +8. The observers received the PowerPoint file contained the images and a questionnaire which included the number of pictures and some relevant questions. They had 3 minutes to give a score to each picture according to their judgement from 1 to 5; 1 for the best and 5 for the worst one. Data were analyzed using descriptive and inferential statistics tests (Independent t- test, chi square and ANOVA and logestic regression model) at p< 0/05 with SPSS 19. All groups found our normal profile as the best one. There were difference among findings of 3 groups(P=0.002). When comparing 2 groups, we did not find difference between omfs and orthodontists. Age and history of cosmetic procedures are factors that have significant effect on people’s perception. The beauty priority among 3 groups are the same but generally there are significant differences between specialists and lay people.

Clinical signs of tooth-size– arch length discrepancy are crowding, impaction, and incisor proclination. The controversy persists over whether to increase the size of the arch by expansion or decrease the size of the teeth by interproximal enamel reduction or extraction to resolve the discrepancy. This report describes the treatment of a 17-year-old girl with a severe tooth size-arch length discrepancy. The patient had a mild Class II skeletal relationship, a high mandibular plane angle, a Class I molar relationship, bilateral posterior cross bites, and deviated midlines. The final treatment protocol was non-extraction treatment of both arches using passive self-ligate brackets. Results and The final treatment result was satisfactory. Proper over- bite and over jet, facial balance and good occlusion were achieved. Expansion of posterior segments and distal movement of molars solved tooth size-arch length discrepancy.

Cone-beam computed tomography (CBCT) is becoming established as a superior radiographic technique to conventional radiography in orthodontics. However cephalometric analysis in conventional lateral cephalograms (LC) is still an important tool in treatment planning. The aim of this study was to compare cephalometric measurements performed on conventional cephalograms with those on CBCT generated images. Method and materials: 24 patients with both LC and volumetric CBCT imaging (Newtom 3G) were selected. Generated Lateral cephalograms (GLC) were produced from related DICOM files in Dolphin 3D. cephalometric analysis, consisted of fifteen angular measurements and fifteen linear measurements (Dolphin V.11.2) were performed on both LCs and GLCs. Paired T-Test was used to compare differences in measurements between the two image modalities. According to paired t-test results no statistically significant differences were found between the two set of measurements except Articular Angle, Gonial Angle (Ar-Go-Me) and Ramus Height (Ar-Go) (P<0.05). Since in all cases the interval between LC and CBCT imaging was short (3.5 months ± 2) and treatment has began after CBCT imaging, neither growth nor treatment was the cause of these differences. It could be supposed that the technical positioning errors in LCs of some patients might be the cause. LC could successfully be replaced by GLC. Since we can select the best orientation of the skull before generating GLC from CBCT DICOM files, GLC could be more reliable than LC.

The aim of present study was to predict post treatment space available of mandibular arch and compare this method of measurement with the previous methods. Pretreatment lower dental arch models of 33 patients attending to the department of orthodontics of Tehran University of medical sciences were randomly selected. Two conventional methods of brass wire and sectional way were done for estimating space available in traditional method. In predictive method two mathematical arch forms, βfunction and the sixth degree polynomial function were selected as the based arches. Post treatment arch perimeter predicted according to these arch forms separately and finally the results were compared with traditional method of brass wire. According to this study, two traditional methods are so closed to each other and also two predictive methods, but differences between traditional method and predictive methods measurements were considerable. Using of post treatment arch parameters would be useful to predict post treatment space available in arches, and also detecting arch form, the position of the teeth, the retention requirements and so on.

G-axis which is defined by the angle between line S-N and S-G would be of great use in evaluation of the mandibular growth relative to other craniofacial structures the aim of this study was to evaluate the correlation of Gaxis with vertical parameters in adult patients of different malocclusions. Lateral cephalograms of 90 patients with different malocclusions, were traced for evaluation of some horizontal and vertical cephalometric facial parameters. The patients were classified into three groups of 30 on the basis of clinical examination, ANB angle and wits appraisal. Pearson correlation test were conducted to compare the correlation of G axis with vertical parameters in different malocclusions. Y-axis length showed significant and positive correlation with G-axis length. G-axis length and lower facial height had positive significant correlation in three categories. No significant correlation was found between G-axis length and ANB angle or wits. Application of the Y-axis and G-vector simultaneously seem to be more useful in cephalometric evaluation of mandibular growth pattern than emphasis on one.

There are no strict criteria in determining the need for orthodontic treatment and dentists often have different opinion on assessing the orthodontic treatment needs. Making an appropriate estimation of the need and demand for orthodontic treatments is necessary to organize and provide meaningful orthodontic services. In this study, the orthodontic treatment needs were evaluated in highschool boys of Yazd. 420 students who were studying in 14 different high schools were randomly selected. All participants were examined under normal white light and DHC(dental health component) ruler. To assess the orthodontic treatment needs, the dental health component of IOTN index was used. The data were analyzed by Chi-square test and pvalue was 0.05. Measurements showed that 44.8% of students scored 1, 15.1% scored 2, 13.6% scored 3, 15.3% scored 4 and 10.7% scored 5 in DHC records. The most frequent malocclusions observed in this study population were contact point displacement (27.3%), crossbite (13.3%), hypodontia (12.8%) and increased overjet (9.3%). Based on the results, approximately one fourth of participants had definite need for orthodontic treatments (IOTN Grades 4 and 5) which is a warning sign. More studies are needed to be done on different populations of the country to make the governors able for organizing oral health programs and providing beneficial dental insurance.