|Year : 2016 | Volume
| Issue : 3 | Page : 252-255
Reliability of panoramic radiography in assessing gonial angle compared to lateral cephalogram in adult patients with Class I malocclusion
Girish Katti1, Chandrika Katti2, Karuna1, Syed Shahbaz1, Munnawwarulla Khan1, Sreenivas Rao Ghali1
1 Department of Oral Medicine and Radiology, Al-Badar Rural Dental College and Hospital, Gulbarga, Karnataka, India
2 Department of Orthodontics, Al-Badar Rural Dental College and Hospital, Gulbarga, Karnataka, India
|Date of Submission||17-Dec-2015|
|Date of Acceptance||05-Dec-2016|
|Date of Web Publication||13-Dec-2016|
Dr. Syed Shahbaz
Department of Oral Medicine and Radiology, Al-Badar Rural Dental College and Hospital, Gulbarga, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Gonial angle is an important angle of the craniofacial complex. Lateral cephalogram and orthopantomogram (OPG) can be used to determine this angle. Objectives: To investigate whether OPGs can be used as an alternative to lateral cephalogram for measuring the gonial angle. Study Design: A total of 100 radiographs were collected from patients with Angle's Class I malocclusion (50 males and 50 females) with age ranging from 15 to 30 years, with a mean age of 18.24 years. Materials and Methods: The radiographs were taken with digital panoramic system (Kodak 8000C) under standard exposure factors, as recommended by the manufacturer. Gonial angle was determined by the tangent of the inferior border of the mandible and the most distal aspect of the ascending ramus and condyle on both panoramic and cephalometric radiographs. Statistical Analysis: Mean values were evaluated using z test. The statistical analysis was performed by using the Statistical Package for the Social Sciences (version 11.5). Results: The mean gonial angle was 121.13° and 122.22° on panoramic and cephalometric radiographs, respectively. There was no statistical significant difference between the measured gonial angles on panoramic and cephalometric radiographs (P > 0.005). Conclusion: Panoramic radiography can be used to determine the gonial angle as accurately as lateral cephalogram. In addition, we can determine the right and left gonial angles of a patient in an OPG without interferences due to superimposed images of anatomical structures in lateral cephalogram.
Keywords: Gonial angle, lateral cephalogram, orthopantomogram
|How to cite this article:|
Katti G, Katti C, Karuna, Shahbaz S, Khan M, Ghali SR. Reliability of panoramic radiography in assessing gonial angle compared to lateral cephalogram in adult patients with Class I malocclusion. J Indian Acad Oral Med Radiol 2016;28:252-5
|How to cite this URL:|
Katti G, Katti C, Karuna, Shahbaz S, Khan M, Ghali SR. Reliability of panoramic radiography in assessing gonial angle compared to lateral cephalogram in adult patients with Class I malocclusion. J Indian Acad Oral Med Radiol [serial online] 2016 [cited 2019 Apr 19];28:252-5. Available from: http://www.jiaomr.in/text.asp?2016/28/3/252/195668
| Introduction|| |
Gonial angle is an important angle of the craniofacial complex. It is significant for the diagnosis of craniofacial disorders. It is one of the important parameters giving an indication regarding the vertical parameters and symmetry of the facial skeleton. The gonial angle is measured by taking the tangent to the posterior border of the ramus and tangent to the lower border of the mandible. The gonial angle depicts the form and shape of the mandible, has a pivotal role in forecasting future mandibular growth, and has certain effects on the profile, changes, growth and position of the mandibular anterior teeth.
Panoramic radiography is frequently used in orthodontic practice to provide important information about the teeth and their axial inclinations, maturation periods and surrounding tissues.,,,, Panoramic X-ray technology is commonly accessible and is used in daily clinical routine to assess mandibular vital structures bilaterally. Panoramic radiography allows the visualization of right and left sides of craniofacial structures by producing an accurate, predictable image of all the teeth and related structures in the shortest possible time, with the least amount of radiation to the patient and to the operator.
Shahabi et al. also concluded that panoramic radiography can be used to determine the gonial angle as accurately as a lateral cephalogram. They also mentioned that, in panoramic radiography, the right and left gonial angles can be measured easily without superimposition of anatomic landmarks, which occur frequently in lateral cephalograms. At present, lateral cephalograms are used for determining gonial angle and Frankfurt mandibular angle; however, in this method, measuring individual gonial angle becomes difficult due to the superimposed images of anatomical structures in a lateral cephalogram. However, panoramic images have the advantage of reduced superimposition of anatomical structures. The gonial angle assessed from a panoramic film was almost identical to that measured on a dried mandible because it can be determined more easily in an orthopantomogram (OPG) than in a lateral cephalogram. In the light of the abovementioned literature, this study intends to compare the accuracy of gonial angle measurements obtained from the two different radiographic views.
| Aim and Objectives|| |
To investigate whether panoramic radiographs can be used as an alternative to lateral cephalogram for measuring the gonial angle.
| Materials and Methods|| |
The study was conducted among 100 patients with Class I malocclusion who visited our dental college for orthodontic treatment. A total of 50 male and 50 female patients were included in the study with age ranging from 15 to 30 years. Before the commencement of the study, each participant was well informed about the study and a written consent was obtained from them. The ethical clearance to conduct the study was obtained from institutional ethical committee of the college.
- Patients with Class I malocclusion
- High quality radiographs with adequate sharpness were taken by the same apparatus and in a natural head position.
- Patients with a previous history of facial or mandibular surgery or syndromes affecting the jaw or face
- Patients with Class II and Class III malocclusion.
All these radiographs were taken with a digital panoramic system (Kodak 8000C) under standard exposure factors, as recommended by the manufacturer. The gonial angle was determined by the tangent of the lower border of the mandible and the distal border of the ascending ramus and the condyle on both panoramic and cephalometric radiographs [Figure 1] and [Figure 2]. The magnification factor used for the machine was 1.15.
The recorded data were analyzed using the Statistical Package for Social Sciences version 11.5 software (SPSS Inc., Chicago, IL, USA). Descriptive statistics included computation of means and standard deviations. The mean values obtained were evaluated using z test. For all tests, P value was set at ≤0.05, respectively.
| Results|| |
A total of 100 panoramic and 100 lateral cephalometric radiographs were obtained. Age ranged from 15 to 30 years, with the mean age of 18.24 years. The mean value of the gonial angle in lateral cephalogram was 122.22° with a standard deviation of 4.97°. The gonial angle in females was 123.81° and that in males was 122.22°, with no statistically significant difference between the two genders. The mean value of the gonial angle in panoramic radiographs was 121.13° with a standard deviation of 4.95°. The gonial angle in females was 122.55° and that in males was 121.13°, with no statistically significant difference between the two genders. In panoramic radiographs, the mean value of the right gonial angle was 120.95°, with a standard deviation of 4.98°, and the mean value of the left gonial angle was 121.31° with a standard deviation of 4.92° [Table 1].
|Table 1: Mean, standard deviation, and range of gonial angle in lateral cephalogram and OPG in degrees|
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There were no significant differences between the values of gonial angle determined by lateral cephalogram and panoramic radiography (P = 0.236). Furthermore, in panoramic radiography, there was no significant difference between the right and left gonial angles (P = 0.712) [Table 2]. In addition, gender did not have a considerable effect on the gonial angle in both radiographs. The results of the present study showed that the difference between the mean gonial angle in lateral cephalogram and panoramic radiography was 1.26° in females and 1.09° in males and the difference between males and females was 0.17°. Because P > 0.05 for all the variables mentioned above, these differences were not statistically significant [Graph 1].
|Table 2: P values related to comparison of gonial angle in lateral cephalogram and OPG|
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| Discussion|| |
The gonial angle is one of the most important measurements required for orthodontic treatment and orthognathic surgery. The gonial angle is also a representation of the form of the mandible. This angle has an important role in predicting growth, and it also has specific effects initially on the growth, profile changes, and the condition of the anterior teeth of the lower jaw., Our study was performed to assess and compare the measurements of the gonial angle from panoramic radiograph and lateral cephalogram. The use of panoramic radiography in the determination of the gonial angle has been studied and the results have shown that the gonial angle measurement on the panoramic radiograph is an accurate and repeatable criterion.,
Assessment of the angle on the right and left panoramic radiographs makes it possible to accurately evaluate the changes after orthodontic treatment. Panoramic radiography has been reported to have potential in measuring mandibular inclination and gonial angle. It has been successfully used for determining gonial angle, which is a good indicator of mandibular steepness and growth direction. Because dentists routinely request OPG during dental examination, for determining growth direction, they can also detect the vertical growth problems.
In the present study, the mean values of the external gonial angle were 121.13° and 122.22° in the panoramic radiograph and lateral cephalogram, respectively, with no significant difference between the two radiographs (P = 0.236), which is in accordance to various studies such as those by Mattila et al. and Larheim and Svanaes. Fisher-Brandies et al. indicated that gonial angle obtained by panoramic radiography was 2.2–3.6° less than that of lateral cephalogram. They observed significant differences in the gonial angle by the two different radiographs, which was in contrast to the results reported in this study. The disparity in the results could be because the type of malocclusion and age of the samples was not specified in the abovementioned study, while the present study was performed in adults with Class I malocclusion.
In our study, there was no statistical difference between the right and left gonial angles in the panoramic radiograph (P = 0.712), which is concurrent with the results of previous studies by Mattila et al. and Altonen et al. Akcam et al. stated that, even though panoramic radiographs provide information on the vertical dimensions of craniofacial structures, clinicians should be vigilant when predicting skeletal cephalometric parameters from panoramic radiographs because of their lower predictability. The results of this study showed that there were no significant differences between the mean values of the external gonial angle in the panoramic radiograph and lateral cephalogram (1.20°) and the mean values of the right and left gonial angles in panoramic radiographs (0.34°). The left and right gonial angles can be determined using an OPG because there are no interferences caused by superimposed images. Hence, for measuring gonial angle, an OPG seems to be a better choice than lateral cephalogram.
| Conclusion|| |
To conclude, panoramic radiography can be used to determine the gonial angle as accurately as lateral cephalogram. Furthermore, in panoramic radiography, the right and left gonial angle scan is measured easily without superimposition of anatomic landmarks, which occurs frequently in a lateral cephalogram. Therefore, it seems that panoramic radiography which is a simple, inexpensive and available radiologic technique can be used for determination of the right and left gonial angles.
Department of Oral Medicine and Radiology, Al-Badar Rural Dental College and Hospital Gulbarga, Karnataka.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]