|Year : 2015 | Volume
| Issue : 4 | Page : 527-531
Reliability of single panoramic radiograph with vertical and horizontal parallax; and intraoral periapical radiograph with Clark's rule compared to computed tomography/surgical exposure in localization of impacted permanent maxillary canine
Vijay Kumar Bokkasam1, Sathish Babu Devaki1, Ravi Raj Jayam1, Pavani Muddepalle1, Charitha Marisetty1, Abhinaya Reddy Tupalli2
1 CKS Theja Institute of Dental Sciences and Research, Tirupathi, Andhra Pradesh, India
2 Department of Pedodontics and Preventive Dentistry, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India
|Date of Submission||23-Dec-2014|
|Date of Acceptance||18-May-2016|
|Date of Web Publication||19-Aug-2016|
Dr. Pavani Muddepalle
Department of Oral Medicine and Radiology, CKS Theja Institute of Dental Sciences and Research, Chadalawada Nagar, Renigunta Road, Tirupathi - 517 506, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aim: The aim of the study was to evaluate an accurate, inexpensive and low-radiation conventional radiograph suitable for localization of impacted maxillary permanent canine. Materials and Methods: The study comprised 38 subjects in the age group of 13-50 years of both the genders with 50 impacted canines. Panoramic radiographs (OPGs) (on which Chaushu et al. criteria was applied) and intraoral periapical radiographs (IOPARs) (on which Clark's rule was applied) of the subjects were made and the accuracy of the above two radiographic techniques were compared with computed tomography (CT) axial sections or with surgical exposure, which was considered as the standard guide for localization of impacted maxillary permanent canine. The data obtained was tabulated and subjected to statistical analysis using the statistical package for SAS software. Results: Localization of impacted maxillary permanent canine tooth done with SLOB (Same Lingual Opposite Buccal)/Clark's rule technique could predict the bucco-palatal canine impactions in 98% of cases. OPG using differential magnification index could predict location only in 68% of bucco-palatal canine impactions and in 72% based on vertical position. Conclusion: In 68% of cases the bucco-lingual position of the canine in OPG (by magnification index) coincided with the location as per CT/surgical exposure. In 98% of cases localization with SLOB technique coincided with CT/surgical exposure. 72% of cases showed coincidence with vertical position of the canine on OPG with CT/surgical exposure. IOPARs taken with SLOB technique are more accurate than OPGs for localization of impacted permanent maxillary canine teeth.
Keywords: Clark′s rule, CT/CBCT, impacted canine, IOPAR, localization, magnification index, panoramic radiography, SLOB, vertical restriction criteria
|How to cite this article:|
Bokkasam VK, Devaki SB, Jayam RR, Muddepalle P, Marisetty C, Tupalli AR. Reliability of single panoramic radiograph with vertical and horizontal parallax; and intraoral periapical radiograph with Clark's rule compared to computed tomography/surgical exposure in localization of impacted permanent maxillary canine. J Indian Acad Oral Med Radiol 2015;27:527-31
|How to cite this URL:|
Bokkasam VK, Devaki SB, Jayam RR, Muddepalle P, Marisetty C, Tupalli AR. Reliability of single panoramic radiograph with vertical and horizontal parallax; and intraoral periapical radiograph with Clark's rule compared to computed tomography/surgical exposure in localization of impacted permanent maxillary canine. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2022 Nov 28];27:527-31. Available from: http://www.jiaomr.in/text.asp?2015/27/4/527/188725
| Introduction|| |
Canines play a vital role in facial appearance, dental aesthetics, arch development and functional occlusion.  Maxillary canines are the second most frequently impacted teeth after the third molars, with prevalence from 1% to 3%. Impacted canines can lead to varying degrees of resorption of the adjacent teeth, particularly of the lateral incisor. Root resorption can be difficult to diagnose with traditional two-dimensional (2D) radiography, particularly if the canine is in direct palatal or facial position to the lateral incisor roots.  Proper treatment requires accurate diagnosis of the localization of impacted maxillary permanent canine tooth in relation to adjacent structures, assessment of root resorption and change in root morphology.  Early methods for localization of impacted maxillary canines involved the use of intraoral radiographs. A simple but useful method was proposed by Clark et al. and is now referred to as the tube-shift or parallax method.  In addition to the intraoral periapical radiographs (IOPARs), panoramic radiographs (OPGs) have also been used to localize impacted teeth. One of the most widely used methods for objectively describing the location and angulations of an impacted canine as viewed on a OPG were developed by Gavel et al.  The use of computed tomography (CT) overcomes the limitations of conventional radiography. , CT was found to be superior to conventional radiographs for the localization of impacted canines and in the assessment of incisor root resorption.  Due to the high-effective dose and cost of a scan, using CT for routine analysis of localization of impacted maxillary permanent canine tooth may be unjustified. Hence, in this study conventional radiographic accuracy was compared with that of CT/Cone Beam CT (CBCT) in localization of impacted maxillary permanent canine.
| Materials and Methods|| |
The study group included patients with 50 impacted canines; clinically missing and impacted corresponding maxillary permanent canines, either unilateral or bilateral and with completely erupted central incisors were the sample of the study. All the patients were above the age of 13 years with completely erupted ipsilateral central incisor. Subjects with a labial prominence or fullness in canine region clinically, those with pregnancy and with micro/macrodontia and developmental abnormalities were excluded. Consent from the subjects as well as ethical clearance from ethical committee had been taken prior to the study. OPGs were taken with conventional panoramic machine - Rotograph Plus, model no. 82088150, Villa, Italy with a magnification factor of 1.1, with specification of 10 mA, 85 kvp for the application of Chaushu et al. criteria with 5 × 12-inched Kodak film. Two IOPARs for each impacted canine with short cone and Same-Lingual, Opposite-Buccal (SLOB) technique [Figure 1] were made on each study subject with intra-oral periapical radiographic machine - Confident Dental Equipment Ltd, India model no-C 70-D, specifications-rating 70 kvp, 7 mA, 230 Watts, 50 Hz, 5A and intra oral periapical film 31 × 41-mm-sized Kodak E speed film. Measurements were made on the radiographs with digital calliper. CT [Figure 2]/CBCT images made for 33 samples with coronal and axial sections with slice thickness 2 mm determined the position of impacted maxillary canine tooth, and the remaining 17 samples were subjected to surgical exposure to determine the position of impacted maxillary canine tooth as standard guide to compare with conventional radiographic techniques [Figure 3].
|Figure 1: (a) IOPAR taken with standard vertical angulation of +45 and 0 degrees horizontal angulation using short cone and (b) IOPAR taken with distal horizontal angulation|
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Magnification index was calculated as below [Figure 4]:
|Figure 4: Measurements of mesiodistal width of impacted canine and ipsilateral incisor for CII|
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- The widest mesiodistal dimension of the displaced maxillary canine tooth was measured on a line perpendicular to its long axis
- The widest mesiodistal dimension of the homolateral central incisor was measured on a line perpendicular to its long axis
- In each case in which the contralateral canine was in the correct position, its widest mesiodistal dimension was similarly measured.
The ratio of the widest mesiodistal dimension of the canine to that of homolateral central incisor was defined as the canine-incisor index (CII). Unilateral cases with a normally located contralateral canine were used as controls, and the ratio of the widest mesiodistal dimension of the affected canine to that of the unaffected canine was defined as the canine-canine index (CCI).
Vertical restriction criteria
The height of the crown of each displaced canine was assessed in the vertical plane relative to the adjacent erupted incisor [Figure 5], which was arbitrarily divided into three zones.
|Figure 5: Vertical position of impacted canine in relation to adjacent tooth on OPG|
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- The apical zone included the apical third of the root;
- The middle zone consisted of the middle third of the root;
- The coronal zone was the remainder of the root.
| Results|| |
[Table 1] shows the distribution of impacted maxillary canines on OPG, CT/surgical exposure. It shows the unpredictability of apically placed canines in bucco-palatal localization with OPG. SLOB study shows that out of 50; 21 are located buccally (42%), 19 were located palatally (38%) and 10 were located in the line of arch (20%) [Table 2]. [Table 3] shows that out of 50 impacted maxillary permanent canine teeth, 30 impacted maxillary canines were buccally located, and 20 were impacted maxillary canines located palatally. [Table 4] shows that the CII values are unreliable for apically positioned canines and canines located in the line of arch. [Figure 6] shows a bar diagram depicting the percentage of coincidence of bucco-palatal position of impacted permanent maxillary canines assessed with conventional radiographic techniques to CT/surgical exposure. There was no significant difference between IOPARs and OPGs when coincided with the CT against alternative hypothesis (H1); IOPAR was superior to OPG when coincided with the CT. [Table 5] shows that 98% of cases studied using IOPARs coincided with CT, whereas with OPG only 68% of cases coincided with CT. Hence we can say that the IOPAR is more effective (consistent) than the OPG. Also for testing significance of radiographs between IOPAR and OPG, t-test was applied and the results were highly significant. Hence we rejected Null hypothesis (accept alternative hypothesis). Therefore, the present study showed that the IOPAR is superior to OPG for localization of impacted permanent maxillary canine teeth.
|Figure 6: Bar diagram showing comparison of conventional radiographic techniques in relation to CT/surgical exposure. (A) % of cases coincide bucco-palatal position of the canine with CII index by CT/surgical exposure, (B) % of cases assessed with IOPARs taken with SLOB technique coincide with CT/surgical exposure, (C) % of cases coincide vertical position of the canine on OPG with CT/surgical exposure, and (D) % of cases coincide bucco-palatal position of middle and coronal canines with CII index by CT/surgical exposure|
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|Table 1: Distribution of maxillary canine locations in OPG and CT/surgical exposure |
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|Table 4: CII values by bucco - palatal position and vertical position of canine in OPG compared with CT/surgical exposure |
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|Table 5: Significance between IOPAR and OPG when compared to CT ('t ' test procedure, Variable: Score) |
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| Discussion|| |
Early localization of the impacted maxillary canine is important as interceptive treatment, so that extraction of the deciduous predecessor can allow spontaneous correction in many cases. Such localization is done by a combination of clinical and radiographic finding.  Previous studies attempted to localize impacted maxillary canine teeth from OPGs alone, based on magnification index i.e., mesio-distal dimension of impacted maxillary canine and vertical restriction criteria concluding OPG as a reliable indicator when compared with surgical exposure as a standard guide. ,,,,,,, Few studies compared single OPG using SLOB technique as a standard guide for localization of impacted maxillary canine teeth. ,, When canines are placed in coronal and middle zone, the OPG along with the CII could predict 85% of the bucco-palatal position of impacted canines. Most of the canines which are present in the coronal zone are located bucally, and those in the middle zone are located palatally. Apically positioned canines had variable bucco-palatal presentations; most of them (45.45%) were present in the line of arch.
From the present study the correct prediction of palatal or labial canine impactions using differential magnification index on dental OPG was possible in about 85% when they were in the middle and coronal zone. This is in agreement with the other studies. ,,,, In the present study, 98% of cases assessed with SLOB/Clark's rule coincided with bucco-palatal position of canines with CT/surgical exposure, whereas Ericson and Kurol et al. reported that IOPARs were more accurate and reliable for location of the teeth in 92% of the cases they evaluated.  In the present analysis, 98% of cases done with IOPARs coincided with CT, where as only 68% cases taken with OPGs coincided with CT. Hence, we can say that the IOPAR by SLOB technique is more effective (consistent) than the OPG.
| Conclusion|| |
Among the conventional radiographs IOPAR taken with SLOB technique is superior to OPG for localization of impacted permanent maxillary canine teeth. The CII index for apically positioned canines is unpredictable and we need further studies with the big samples to evaluate for prediction of CII for the same.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]