|Year : 2023 | Volume
| Issue : 1 | Page : 6-10
Assessing the relationship between the intercondylar distance and mandibular intercanine distance in orthopantomogram – A retrospective study
Praveena Prabhakar, RR Mahendra Raj, Thalaimalai Saravanan, Shakila Ramalingam
Department of Oral Medicine and Radiology, Karpaga Vinayaga Institute of Dental Sciences, Chengalpattu, Tamil Nadu, India
|Date of Submission||17-Oct-2022|
|Date of Decision||19-Jan-2023|
|Date of Acceptance||03-Feb-2023|
|Date of Web Publication||18-Mar-2023|
Dr. Praveena Prabhakar
Department of Oral Medicine and Radiology, Karpaga Vinayaga Institute of Dental Sciences, GST Road, Chinnakolambakam, Palayanur, Chengalpattu - 603 308, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Background: In completely edentulous patients, it is necessary to replace the teeth with at most esthetics and comfort with less patient strain. Aim: The current retrospective study was done to find the relationship between the intercondylar distance and intercanine distance of the mandible by obtaining the ratio using an orthopantomogram (OPG) for lower anterior teeth selection in completely edentulous patients. Materials and Methods: The OPG of 500 subjects was selected randomly. The OPGs were taken using the Sirona Orthophos XG machine and exposed for 14.1 s at 64 kvp, 8 mA. Then, the intercondylar distance and mandibular intercanine distance were measured from the soft copy of the OPG using the software “Sidexis.” The required measurements were taken digitally from the OPG using the software “Sidexis” in millimeters (mm). The SPSS software version 22.0 was used for statistical analysis. Results: Pearson correlation coefficients (r) displayed a significant positive association between the intercondylar distance and intercanine distance of the mandible (r = 0.42; P = 0.0002). The correlation between intercondylar width and mandibular intercanine width was significant and positive for men (r = 0.26, P = 0.0003) but negative for women (r = −0.41, P = 0.0001). The ratio between the mean intercondylar width and the mean intercanine width was 1:4.90. Conclusion: The mandibular intercanine distance and the intercondylar distance have a positive and significant association. The ratio obtained in this study was 1:4.90 between the mandibular intercanine distance and the intercondylar distance that could be employed for the choice of mandibular anterior teeth.
Keywords: Anterior teeth selection, complete denture, esthetic, intercondylar distance, mandibular intercanine distance, orthopantomogram
|How to cite this article:|
Prabhakar P, Mahendra Raj R R, Saravanan T, Ramalingam S. Assessing the relationship between the intercondylar distance and mandibular intercanine distance in orthopantomogram – A retrospective study. SRM J Res Dent Sci 2023;14:6-10
|How to cite this URL:|
Prabhakar P, Mahendra Raj R R, Saravanan T, Ramalingam S. Assessing the relationship between the intercondylar distance and mandibular intercanine distance in orthopantomogram – A retrospective study. SRM J Res Dent Sci [serial online] 2023 [cited 2023 May 31];14:6-10. Available from: https://www.srmjrds.in/text.asp?2023/14/1/6/372000
| Introduction|| |
The mandible is one of the hardest and largest bones in the human skull which is a moveable part articulated with the skull. It has sexual dimorphism which can be differentiated by its size in general, chin shape, gonial angle, and gonial flare. It is composed of the following parts the body, ramus, symphysis, condyle, and coronoid process. The condyles articulate in the glenoid fossa forming the temporomandibular joint. The development of the mandible is from the first pharyngeal arch. The anterior teeth of the mandible are vital mechanically and physiologically. The relationship between the intercondylar width and the mandibular intercanine width plays an important role in the determination of the requirement of the anterior teeth that have to be replaced.
It also plays a vital role in the esthetic restoration of the mandibular anterior teeth. However, in literature from the origin of the prosthetic treatment, much of the importance is given to the selection of the maxillary anterior teeth for esthetic treatment. Since ideal tooth selection is the first factor that improves the comfort, esthetics, and function of the patient, priority is always given to the proper selection of the teeth. Esthetics has got most of the appreciation in designing the prosthesis, and it is defined according to Young as “It is apparent that beauty, harmony, naturalness, and individuality are major qualities” of esthetics.
The choice of the anterior teeth of the mandible is based on a number of anatomical landmarks, including the facial form and labial vestibule of the mandible. However, the soft tissue landmarks are subjected to change due to unstable face form concept due to alterations in the face with increasing age., Hence, the intercondylar distance which is not subjected to change significantly can be used as a protocol to determine the size of the lower anterior teeth to be replaced.
At the same time, due to the high remodeling capacity of the mandible, especially the alveolar bone, it keeps on changing the location and position of the alveolar process inward posteriorly which further results in the narrowing of the anterior mandible. According to research done in a dog, the buccal or lingual plates resorb in two overlapping periods, the bundle bone is resorbed in the first phase and is replaced by woven bone, while the outside surfaces of both bone walls are resorbed in the second phase. In 1881, Roux suggested that the loss of alveolar bone occurring after tooth loss is due to disuse atrophy in old age. Hence, the teeth missing should be replaced properly. As a result of tooth loss, the morphology of the mandible changes, which can be seen as a widening of the gonial angle and a shortening of the height of the ramus and the condylar height. These results underline the significance of masticatory system rehabilitation in order to keep the masticatory muscles in good working order for as long as possible. However, these changes occur only if the subject is edentulous for a long period of time, so it should be considered in long-term edentulous patients during teeth replacement.
An orthopantomogram (OPG) is a common radiograph used to identify the hard tissues of the mouth and the nearby skeletal structures. Resolution can help identify dental diseases such as caries (decay), periodontal bone loss, abscess, and cyst formation, for the inspection of the teeth, but it is less accurate than intraoral radiography. Gross modifications in the ossification of the underlying mandible and maxilla as well as alterations in the calcification of the dental tissues can be beneficial.
Bilateral information on the mandible is provided by OPG of the middle and lower one-third of the head. Regarding the location of the head in the OPG, the accuracy of the vertical two-dimensional images of the two condyles and their rami has been demonstrated. The image shows an oblique portion of the articulating surface of the condyle. This cross-size section shows the dimension that is influenced by the patient's posture in reference to the Frankfort horizontal plane when in the head positioner in relationship to the condyle's shape and the central beam. An overview of the vertex of the condyle is always where the image begins. The aim of the current retrospective study was to find the relationship between the intercondylar distance and intercanine distance of the mandible by obtaining a ratio using an OPG for lower anterior teeth selection in completely edentulous patients.
| Materials and Methods|| |
This retrospective study was done after obtaining approval from the Institutional Ethics Committee, Karpaga Vinayaga Institute of Dental Sciences Ethics Committee (Reg. EC/NEW/INST/2020/112), October 15, 2022, KIDS/IEC/2022/III/018. The study procedures were all carried out in conformity with the ethical guidelines outlined in the 2013 revision of the 1964 Declaration of Helsinki.
The OPG of 500 edentulous patients inclusive of both males and females were selected randomly from all the age groups and grouped as 0–18, 18–35, 36–64, and >65.
The OPGs were taken from the Sirona Orthophos XG machine with Frankfort's horizontal line in 90° to the floor and also center the laser light in the midsagittal plane.
The patient was made to stand erect and asked to position the upper and lower central incisors on the notch in the bite block and bite gently for proper positioning of the teeth, and they are asked to press the tongue on the hard palate. All the metal objects, eyeglasses, and jewelry were removed from the patient, and lead aprons were given to the patients to protect their reproductive organs as a radiation protection protocol. The patient is made to remain stationary until the process of taking the X-ray.
The exposure was done for 14.1 s at 64 kvp, 8 mA, and the image is saved as a soft copy. The required measurements were taken digitally from the OPG using the software “Sidexis” in millimeters (mm). Since two parameters were taken, the reference points for the measurement of both intercondylar distance and mandibular intercanine width were selected prior to the start of the study. The intercondylar distance is taken from the center of the condyle on the glenoid fossa from the right side to the left side. The intercanine width of the mandible was measured from the cusp tips of 33 to 43, i.e. from the canine cusp tip on one side of the arch to the canine cusp tip on the other side of the same arch, both the measurements were recorded digitally [Figure 1]. All the measurements in this study were taken in millimeters (mm) and tabulated accordingly [Figure 2] and [Figure 3].
|Figure 1: The above OPG image of a sample shows the reference points from which both the intercondylar distance and mandibular intercanine distance were recorded. OPG: Orthopantomogram|
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|Figure 2: Preoperative image of an OPG before taking measurements. OPG: Orthopantomogram|
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|Figure 3: Postoperative image of an OPG with recorded measurements. OPG: Orthopantomogram|
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The inclusion criteria consisted of healthy patients with no systemic problems that would create an impact on the resorption pattern of the bone which may alter the tooth position from time to time due to pathological migration or mobility, and the study subject should have all the lower anterior teeth, i.e. from the mandibular canine from the right side to the left side. The participants below 18 years were also considered in spite of not attaining skeletal maturity since there were edentulous conditions in patients below 18 years due to anodontia, with no systemic diseases or metabolic changes associated with bone in which the teeth have to be replaced.
The exclusion criteria consisted of patients who have undergone therapeutic extraction or with any malocclusion or those undergoing orthodontic treatment and those who have undergone any endodontic treatment procedures with tooth preparation and crown and also people with attrited canines and those who are edentulous and with systemic problems and those patients who have undergone orthognathic surgery or resective surgical procedures due to any carcinoma. Moreover, patients who had any sort of facial trauma or mandibular fractures, especially condylar fractures, and those patients with temporomandibular disorders that can be detected radiographically were excluded.
The data obtained were recorded in an Excel spreadsheet, and the data were tabulated. The statistical analysis was obtained by using the software SPSS (Statistical Package for the Social Sciences) version 22.0 [ SPSS Inc., Chicago, IL, USA]. Independent sample t-test was applied to compare the means of tooth measurements of the groups, and Pearson's correlation coefficient was applied to find the correlation between the intercondylar distance and intercanine distance of the mandible; P < 0.05 was considered statistically significant.
| Results|| |
For this study, 500 subjects were selected randomly. The majority of the patients, 229 (45.7%), were between the ages of 19 and 35. In the whole study sample of 500 subjects, 274 (54.8%) were men and 226 (45.2%) were women [Table 1] and [Table 2]. Males had an average intercondylar distance of 156.45 mm and females had 122.32 mm, respectively. In males, the average mandibular intercanine width was 32.04 ± 3.06 mm, while in females, the average was 27.80 ± 2.32 mm.
Males had considerably higher intercondylar and mandibular intercanine averages than females. The ratio between the mean intercondylar width and the mean intercanine width is 1:4.90. The selection of teeth can be done directly using this ratio. The Pearson correlation coefficients (r) between the intercondylar distance and intercanine distance of the mandible showed a significant positive correlation (r = 0.42; P = 0.0002) [Table 3]. The computation of correlation coefficients for both genders followed a similar process for both genders. The correlation between intercondylar distance and intercanine distance of the mandible was significant and positive for men (r = 0.26, P = 0.0003) but negative for women (r = −0.41, P = 0.0001). [Table 4] displays partial correlation coefficients. Age had no bearing on the relationship.
|Table 4: Correlation between intercondylar width with mandibular intercanine width|
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| Discussion|| |
In this study, the direct involvement of the patient in the study is avoided so that patients' time is conserved. At the same time, the measurements are taken digitally and stored which is not a time-consuming process. None of the invasive procedures were involved, and no physical or mechanical procedures were included. The data used for the study were the OPGs of the patients which can be stored as a soft copy easily using any software or in any hard disk, and the calculated measurements were directly recorded in excel sheets whereas if casts were fabricated using the impression for measurements instead of OPGs it has to be stored properly and it requires proper area or space. The cost required for the study is very less since the OPGs that were stored prior can be used whereas investment is required for the impression material and other materials used for cast fabrication.
Similar to this study, Keshvad et al. also carried out a study to determine the link between intercondylar distance and intercanine distance of the mandible which helps in teeth setting for fabrication of dentures. The cast fabrication is done after impression taking using laboratory procedures, and the intercanine width is measured using a Vernier caliper and is confirmed by calculating it three times. Moreover, the intercondylar width was measured using the arbitrary face bow. At the same time, there was no significant difference between the recordings made using the arbitrary and kinematic face bow and later it was concluded that an arbitrary face bow is effective for measuring the intercondylar distance. The relation between the intercondylar distance and the intercanine distance of the mandible was found as a ratio of around 1:4.39, which is almost more or less equal to this current study.
Similarly, Qamar et al. conducted a study in which the impressions of both the maxilla and mandible were taken with a perforated metal tray by the use of a two-stage impression technique using additional silicon putty and light body and Type IV dental stone is used for cast preparation. The mandibular intercanine distance was measured from the tip of the cusp of the mandibular canine using an instrument Vernier caliper. The Hanau-H2 arbitrary face bow is used to measure the intercondylar distance at the rest position. The facebow fork is attached to the teeth using silicon impression material. All the necessary markings were made and confirmed by palpation (tragus canthus line and hinge axis). Moreover, the intercondylar distance is measured between the two condylar heads using a Vernier caliper in millimeters three times, and the mean is calculated. The ratio of mean between the intercondylar distance and the intercanine distance of the mandible was 1:5.10 which is almost equal to this study.
However, in this study, the intercondylar distance and mandibular intercanine distance were measured using the OPG which is a two-dimensional image, and the readings were recorded digitally using the computer software “Sidexis.”
Thus, the limitation of the study is that the values are recorded from a two-dimensional image which may be subject to change due to minor errors in measurement or calculation since it is a panoramic image of the three-dimensional subject. There may also be slight variation in the readings due to positioning error of the patients or image distortion caused due to unwanted movement of the patient during exposure which should be considered which was avoided by rejecting the OPGs with image distortion. The intercondylar distance in this case is calculated from the image, whereas in another study, it is taken directly from the patient where the points can be confirmed by palpation of the hard tissue and soft tissue landmarks.
The mean intercondylar distance and mandibular intercanine distance were slightly higher when compared to the results given by Qamar et al. whereas the mean of them was more or less equal. Finally, the correlation was positive and not significant for males in the study conducted by Qamar et al., whereas it is both positive and significant in this study.
In this study, it is discovered that the intercondylar distance can be employed for the anterior teeth selection on the basis of this investigation. The breadth of the intercondylar is considered an authentic landmark in our study by selecting the highest point of the condyle as a reference point for measurement. Although it is not asserted that this method is the only practical way to place teeth, it is an additional aid, particularly for the anterior teeth for individuals who are completely edentulous and have no prior dental treatment records of tooth extraction. Regarding this, there was no evaluation of skeletal connections or ethnic diversity. Additional studies inevitably must be done to ascertain if these various ratios are the result of factors.
| Conclusion|| |
The mandibular intercanine distance and the intercondylar distance had a positive and significant association. The ratio of the mandibular intercanine distance to the intercondylar distance that could be employed was 1:4.90. It can be employed for the choice of mandibular anterior teeth. The intercondylar distance could be quite a useful measure for determining which teeth to use in patients without teeth. The average mandibular intercanine distance and intercondylar distance were significantly higher in men than in women according to this study.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]