ORTHODONTICS
CONE BEAM TOMOGRAPHY AND PANORAMIC RADIOGRAPHY IN LOCALIZATION OF IMPACTED MAXILLARY CANINE AND DETECTION OF ROOT RESORPTION
DOI: https://doi.org/10.25241/stomaeduj.2021.8(2).art.3
Seden Akan1a , Nevin Kaptan Akar2b
1Department of Orthodontics, Faculty of Dentistry, Altınbaș University, Bakırköy / İstanbul, Turkey
2Department of Orthodontics, İstanbul Medipol University Faculty of Dentistry, İstanbul, Turkey
aDDS, PhD, Assistant Professor; e-mail: sedenakandt@hotmail.com; ORCIDiD: https://orcid.org/0000-0001-7955-3086
bDDS, PhD, Assistant Professor; e-mail: nakar@medipol.edu.tr; ORCIDiD: https://orcid.org/0000-0003-1208-6369
Abstract
Introduction The aim of this study was to evaluate cases of impacted maxillary canines (IMC) using cone beam tomography (CBCT) and panoramic images in an attempt to assess if panoramic radiographs can provide information compatible with CBCT results regarding canine position and root resorption.
Methodology Fifty-six impacted maxillary canines from 48 patients were radiographically evaluated. The positions of the canine teeth were classified by Sector localization on panoramic radiographs and the same teeth were also analyzed by KPG on CBCT. Root resorptions in maxillary lateral incisors were also evaluated on CBCT. The relationships between panoramic and CBCT findings were compared by Chi-square test and Fischer’s exact test.
Results Statistically significant correlations were found between panoramic Sectors and KPG indexes (p<0.001). KPG index values of 1, 3 and 4 corresponded to the panoramic Sectors 1, 4 and 5, respectively;
but KPG index 2 matched the panoramic Sectors 3 and more often 2. Mid-alveolar impaction generally coincided with score 1 for both KPG index and panoramic Sector. In palatally IMC, this score value was generally 2 or 3 for the KPG index and 4 for the panoramic Sector (p≤0.001). Root resorptions in maxillary lateral incisors showed significant differences according to Sector localization and KPG index (p<0.05), namely they coincided with 2 and 3 in Sector evaluation and 2, 3 and 4 in KPG index.
Conclusions Sector location on OPG is found to be related to KPG index on CBCT, and it can help evaluate mainly certain positions of impacted canines; thus, unnecessary CBCT scans are not requested.
KEYWORDS
Impacted Canine; KPG Index; Radiography Dental; Digital Radiography Panoramic; Sector Classification.
1. Introduction
Maxillary canines play important roles in facial esthetics, dental arch development, and oral cavity functions. Non-erupted maxillary canines are relatively common because these teeth develop deep within the maxilla and follow a longer path to erupt into the oral cavity when compared to other teeth [1]. An impacted tooth can be defined as the tooth that has failed to erupt into the proper position in the dental arch within the normal period of growth, and maxillary canines are the most common teeth suffering from impaction except third molars. The prevalence of their impaction ranges from 1% to 3% in the general population [2-4].
The determination of impacted canine positions is critical for the planning of orthodontic-surgical treatment. The panoramic radiographic evaluation is the most common clinical approach used by orthodontists for this procedure. It should be known, however, that panoramic radiographs have some limitations in evaluating the labiopalatal positions of impacted canines [5]. In addition, it is difficult to localize and determine the root resorptions of adjacent teeth with this radiographic method because of the superimposition of the related structures, leading to a difficulty in distinguishing many significant details [6].
Many studies have been carried out to overcome these shortcomings regarding panoramic radiographic evaluations [7-11]. One of them belonged to Ericson and Kurol [8] who proposed some measurements on panoramic radiographs to predict the possible impaction of maxillary canines in relation to the adjacent lateral incisors.
Their sector classification was then modified by Leonardi et al [12] and Bacetti et al [13] and gained popularity among the orthodontists and dental radiologists [14,15].
Cone-beam computed tomography (CBCT) used for three-dimensional visualization has gained more popularity in dental clinics during the last 3 decades [16] and at present, it has been accepted as the most accurate method in impacted tooth localization [17] although CBCT gives more radiation to the patients than conventional radiographs. In order to develop evidence-based guidelines on the use of CBCT in dental and maxillofacial imaging, a project named SEDENTEXCT was accomplished between 2008-2011 in Europe [17].
According to this project, CBCT records may be indicated only in cases where inadequate information is obtained from conventional radiographs about impacted canines and their localizations.
CBCT presents a reliable guidance of the used mechanics, force, and treatment style to move the impacted canines efficiently with lower complications. To standardize the classification of impacted maxillary canines and to predict treatment difficulty, KPG index was introduced by Kau et al [18] in 2009. The aims of the present study were to investigate if the panoramic radiographs can provide information related with CBCT results regarding canine position and root resorption.
2. SUBJECTS AND METHODS
This retrospective radiographic study, being approved by the institutional ethical board (108400987-97-86), was carried out on the diagnostic records of 48 patients applied at the Orthodontic Department of the Dental School at Istanbul Medipol University;
the patients complained of maxillary canine impaction. The age of the subjects ranged between 12-34 and the mean age was 18.31±4.99 years. The patients having any syndrome, tooth aplasia, or undeveloped canine root were excluded. Bilateral canine impaction was seen in 8 patients, while 40 of them had unilateral impaction. After a routine panoramic radiographic evaluation, CBCT scans were needed in order to obtain more detailed information on the impacted canines for button operation. Panoramic records (OPG) were obtained by Carestream (Kodak) OPG Dental Machine (Carestream, Canada). CBCT scans were taken by I-CAT Next Generation & i-Cat VisionQ machine, (Imaging Sciences International, LLC, Hatfield, PA) at a setting of 120 kVp and 3.7 m.
Both the OPG records and CBCT images of the 56 impacted canines were analyzed. The mesiodistal positions of the canine crowns were determined on panoramic radiographs and classified by the Sector classification method, which was modified by Leonardi et al [12] and Bacetti et al [13] (Fig. 1).
The KPG index, a novel index based on 3D CBCT images, was calculated by summing the scores (0 to 5 scores) of the canine cusp tip and root tip on x, y and z planes (Fig. 2). The total KPG scores between 0 and 9 were classified as follows: 10 as easy, 14 as moderate, 15 and 19 as difficult and 20 and above as extremely difficult. These categories were named as 1, 2, 3, and 4 beginning from the easy group in order to make the comparison with the Sector groups easy. The root resorptions of adjacent maxillary lateral incisors and labiopalatal positions of the impacted canines were also evaluated on CBCT. The labiopalatal positions of the impacted canines were classified as labial, mid-alveolar, and palatal. Root resorptions were settled as yes or no.
The labiopalatal positions of the impacted canines and resorptions at lateral incisors were correlated with the KPG indexes and Sector classifications.
Panoramic and CBCT images were scored twice by one author (S.A.) at a two-week interval. Intraobserver reliability was assessed by Kappa coefficient.
The relationships between panoramic and CBCT findings were investigated by Chi-square and Fisher’s exact tests. The data analysis was performed using SPSS 16.0 software package (SPSS Inc., Chicago, IL, USA). P values lower than 0.05 were accepted as statistically significant.
3. Results
Kappa coefficients showing intraobserver reliability were high for both panoramic and CBCT images: 0.748 for lateral incisor root resorption and 0.858 for labiopalatal position of the impacted canine. Table I shows a statistically significant association between Sector classification and KPG index (p<0.001). KPG indexes 1, 3, and 4 corresponded to panoramic Sectors 1, 4, and 5, respectively, while KPG index 2 related to panoramic Sectors 2 and 3. The results regarding the labiopalatal positions of the impacted canines and resorptions at the lateral incisors are shown in Table II. As can be seen from these tables, midalveolar impaction generally coincided with score 1 in both KPG and Sector evaluations. The indicative scores were 2 or 3 in the KPG index and; 2, 3 and 4 in panoramic Sectors for palatally impacted canines (p≤0.001). In labially impacted canines, the indicative score was 3 for both KPG index and the panoramic sector. The root resorption of maxillary lateral incisors showed significant differences according to Sector localization and KPG index (p<0.05). Resorption was found more in scores 2 and 3 in both KPG and Sector evaluations.
4. Discussion
The determination of impacted maxillary canine positions is very important to prevent root resorptions in adjacent teeth, to schedule ortho-surgical procedures, and to give an opinion about orthodontic treatment time. It has been stated that one of the major reasons for treatment failure of impacted canines is mistaken location anddirectional of traction (40.5%) [19]. The main objectives of the present study were to assess therelation between 2D and 3D visualization of impacted maxillary canines, to estimate abiopalatal positions of impacted canines from panoramic radiographs, which were routinely used in orthodontic clinics, and to evaluate root resorptions in lateral incisors by CBCT. CBCT is the bestcontemporary method to diagnose and localize the impacted canines and their possible complications [6,20,21]. It has excellent image quality and high diagnostic accuracy for many tasks, such as the detection of bone defects, implant treatment planning, impacted third molar and canine teeth, and root re sorption evaluation.
In the present study, KPG index values obtained according to CBCT were gathered in more localized categories than Sector classification made according to Panoramic radiograph. For example, while lateral tooth contact and root resorption appear only at 2 and 3 in the KPG index, they are evaluated in almost all classes in the Sector classification. This result may suggest once again that the diagnostic capability of the CBCT may be clearer.
According to the radiation dose which is the main disadvantage of the CBCT, although the CBCT exposure dose is relatively low compared with that of conventional CT, it is up to 10 times higher than that of intraoral and extraoral radiography used in dentistry [22,23]. To give a more practical example, it has been revealed that the average effective radiation dose of panoramic radiography is relatively lower, ranging from 4.1 to 36 μSv (2-3 days of natural background radiation level), whereas that of CBCT ranges from 19 to 368 μSv (11 days of natural background radiation level) [24, 25]. Thus, a reason for an examination and optimization of this radiographic technique are strongly needed [26]. It is accepted that CBCT scans should only be requested when there is a potential for CBCT images to provide new information not provided by conventional radiograph [17]. The cases in which diagnosis of impacted teeth is made in initial conventional orthodontic records, CBCT might be requested as a compliment [17]. Should that be the case, CBCT scan protocols should include a partial field of view comprising the maxilla or the mandible, only. In the light of this information, the present study attends to define a correlation between 2D and 3D qualitative analyses, at least when unnecessary CBCT scans are not requested.
The KPG index, introduced in 2009, presents an opportunity to localize the impacted canines using CBCT. Kau et al [27] carried out a study in 2013 to determine the level of agreement of orthodontists in the management of impacted maxillary canines, and found that the KPG index showed a good level of agreement with the clinician’s perception of difficulty. Dalessandri et al [28] investigated the agreement between OPG based 2D measurements and the KPG index on 105 impacted maxillary canines. These authors stated that KPG index had higher intra- and interrater agreement than those of the 2D index, and that yhe KPG index allows clinicians to exactly evaluate the position of impacted canines [28]. As for panoramic radiograph, OPG has been accepted as a standard record in orthodontics. In addition to the clinical examination of the palatal lump, radiographic evaluation is generally needed to identify the positions of impacted canines. With a low radiation dose, OPG provides an overview of all dentoskeletal structures, but several factors, such as superimposition of the structures and inadequate visualization of anterior maxilla in horizontal and vertical planes, affect the image quality of the panoramic radiograph. Sector classification, carried out on OPG, is a very important diagnostic tool used in the evaluation of impacted canines [10,13,29]. Jung et al [15] showed that labially impacted canines were frequently in Panoramic Sectors 1, 2, and 3, mid-alveolus impacted canines in Sector 4, and palatally impacted canines in Sector 5. According to these authors, the labiopalatal positions of impacted canines can be predicted by Sector location on OPG. Olive [29] stated that there was a significant relationship between the mesiodistal position of impacted canines and the treatment time. Canines impacted in Sector 4 emerged after 21 months of treatment and canines in Sectors 2 and 3 emerged after 8 months of treatment.
In literature, there are studies [21,28,30-34] comparing the localization of impacted canine by means of 2D and 3D indexes. Sosars et al [30] evaluated 106 palatally displaced maxillary canines and they concluded that panoramic measurements were not reliable predictors of resorptions, except for severe resorptions, of the neighbor teeth. Khan Mohammed et al [31] stated that CBCT showed an increased accuracy of 31% compared to Panoramic radiography in localizing impacted maxillary canines. Haney et al [32] compared the differences between 2 imaging modalities regarding diagnosis and treatment planning ofimpacted maxillary canines. Two and three dimensional images of 25 impacted canines were evaluated by 7 of their faculty members, and significant disagreement was observed among the evaluators. As a result, they concluded that three-dimensional volumetric imaging might provide more accurate information for diagnosis and treatment plans. In a similar study carried out by Alqerban et al [21], OPG and CBCT images were obtained from 60 consecutive patients who had impacted or ectopically erupting maxillary canines, and these images were analyzed by 11 examiners. The results of that study showed that CBCT was more sensitive than conventional radiography for both canine localization and identification of root resorption of adjacent teeth. Altough recent studies have shown that CBCT is the most sensitive and reliable technique in the evaluation of craniofacial structures, as stated previously, it gives higher radiation doses to the patients than the conventional radiographs, thus it has not come into use routinely in orthodontic clinics [33]. For this reason, it was necessary to detect possible relationships between Sector classification on OPG and 3D KPG index. If a strong relationship is detected between them, OPG can be used safely in impacted canine cases. The results of the present study showed that KPG indexes 1, 3, and 4 mostly matched panoramic Sectors 1, 4, and 5, respectively, and that KPG index 2 matched Sector 2 and 3.
According to these results, it could be said that the Sector analysis is largely compatible with the KPG index.
The accurate diagnosis of exact canine position, potential contacts, and root resorptions of the adjacent teeth may reduce complications during treatment.
Jung et al [15] found root resorption in the adjacent teeth only in Sectors 3, 4, and 5. Ericson and Kurol [8] stated that canines in the Sectors 3, 4, and 5 comprised 65% of the related root resorptions.
In the present study, all of the root resorptions were in Sectors 2, 3, and 4 and in KPG index 2 and 3. There was no resorption case in Sector 5. As can be seen from Table 1, only 3 teeth of 56 impacted canine teeth were in sector 5, and 2 of them matched KPG index 4. This means that the canines in Sector 5 have a deep localization. But it should not be passed on without being told; these are a rather small numbers for drawing reliable conclusions about these scores. This fact may explain the difference between the results of the present study and those of Jung et al [15] and Ericson and Kurol [8]. These results showed that the Sector classification of the impacted canines may help to detect root resorptions at the adjacent teeth. If Sector evaluation on OPG is 2 or above, root resorption may have been at the adjacent lateral incisors, and thus CBCT evaluation should be recommended for detailed examination. The determination of the labiopalatal positions of the canine cusp tips was an important issue in the diagnosis and treatment planning of impacted canine cases. This evaluation can be made by Sector classification on OPG or KPG index on CBCT [10,15]. Jung et al [15] evaluated 73 impacted maxillary canines of 63 patients by OPG and CBCT, and classified them by sector location.
According to their results, 26 out of the 30 labially impacted canines were located in Sectors 1, 2, and 3, while 15 out of the 23 mid-alveolus impacted canines and 17 out of the 20 palatally impacted canines were in Sectors 4 and 5. In the present study, roughly half of the labially impacted canines had 3 KPG and Sector scores. All mid-alveolar impacted canines had scores 1 and 2 in both KPG index and Sector classification. Of the 33 palatally impacted canines, 29 teeth were in the KPG index 2 and 3 and in Sectors 2, 3, and 4. These results suggest that sector location on OPG could help to predict the labiopalatal positions of the impacted canines as it is done by KPG index on CBCT.
5. Conclusion
The results of the present study can be summarized as follows:
• KPG indexes 1, 3, and 4 corresponded to panoramic Sectors 1, 4, and 5, respectively, while KPG index 2 is
related to panoramic Sectors 2 and 3,
• Lateral incisor root resorption was seen predominantly in KPG index 2 and 3, and in Sectors 2, 3, and 4.
• Score 1 and 2 for both KPG index and Sector classification showed mid-alveolar impaction; score 3 showed labial impaction for both evaluation groups; and score 2 and 3 in KPG index and 2, 3, and 4 in Sector classification were related to palatally impacted canines.
• OPG could help the evaluation of impactedmaxillary canine cases by providing information related to CBCT results.
Conflict of Interest
The authors declare no conflict of interest.
Acknowledgments
None.
Author Contributions
SA: contributed to the concept and design of the study, the acquisition, analysis and interpretation of the data and drafting the article. NKA: participated by adding her patient records and revising the article critically. All authors read and approved the final manuscript.
Funding
The authors declare that they have not received any funding.
Competing interests
The authors declare that they have no competing interests and revised the article critically. All authors read and approved the final manuscript.
Ethics approval and consent to participate
Written informed consent containing all the information about records and usage for study was obtained from all patients. All
procedures in this study were approved by the Ethical Board of the Istanbul Medipol University (108400987-97-86) and complied with the Code of Ethics of the World Medical Association (Declaration of Helsinki).
AUTHOR CONTRIBUTIONS
SA: contributed to the concept and design of the study, to the acquisition, analysis and interpretation of the data and drafting the article. HO: participated by critically revising the article. All authors read and approved the final manuscript.
References
1. da Silva Santos LM, Bastos LC, Oliveira-Santos C, et al. Conebeam computed tomography findings of impacted upper canines. Imaging Sci Dent. 2014;44 (4):287-292. https://doi.org/10.5624/isd.2014.44.4.287 PubMed Google Scholar
2. Thilander B, Jakobsson SO. Local factors in impaction of maxillary canines. Acta Odontol. Scand. 1968;26(2):145-168. https://doi.org/10.3109/00016356809004587 PubMed Full Text Google Scholar Scopus
3. Walker L, Enciso R, Mah J. Three-dimensional localization of maxillary canines with cone-beam computed tomography. Am J Orthod Dentofacial Orthop. 2005;128 (4):418-423. https://doi.org/10.1016/s0084-3717(08)70464-1 PubMed Full Text Cross Ref Google Scholar Scopus WoS
4. Rossini G, Cavallini C, Cassetta M, et al. Localization of impacted maxillary canines using cone beam computed tomography. Review of the literature. Ann. Stomatol. (Roma). 2012;3 (1):14-18. https://doi.org/10.1016/j.tripleo.2007.01.030 PubMed Full Text Links Google Scholar WoS
5. Freisfeld M, Dahl IA, Jager A, et al. X-ray diagnosis of impacted upper canines in panoramic radiographs and computed tomographs. J Orofac Orthop. 1999;60 (3):177-184. https://doi.org/10.1007/bf01365264 PubMed Full Text Links Cross Ref Google Scholar Scopus
6. Almuhtaseb E, Mao J, Mahony D, et al. Three-dimensional localization of impacted canines and root resorption assessment
using cone beam computed tomography. J Huazhong Univ Sci Technolog Med Sci. 2014;34 (3):425-430. https://doi.org/10.1007/s11596-014-1295-z PubMed Full Text Links CrossRef Google Scholar Scopus WoS
7. Stewart JA, Heo G, Glover KE, Williamson PC, Lam EW, Major PW. Factors that relate to treatment duration for patients with palatally impacted maxillary canines. Am J Orthod Dentofacial Orthop. 2001;119 (3):216-225. https://doi.org/10.1067/mod.2001.110989 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
8. Ericson S, Kurol J. Early treatment of palatally erupting maxillary canines by extraction of the primary canines. Eur J Orthod. 1988;10 (4):283-295. https://doi.org/10.1093/ejo/10.4.283 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
9. Crescini A, Nieri M, Buti J, et al. Orthodontic and periodontal outcomes of treated impacted maxillary canines. Angle Orthod. 2007;77(4):571-577. https://doi.org/10.2319/080406-318.1 PubMed CrossRef Google Scholar WoS
10. Lindauer SJ, Rubenstein LK, Hang WM, et al. Canine impaction identified early with panoramic radiographs. J Am Dent Assoc.
1992;123(3):91-92, 95-97. https://doi.org/10.14219/jada.archive.1992.0069 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
11. Warford JH, Jr., Grandhi RK, Tira DE. Prediction of maxillary canine impaction using sectors and angular measurement. Am
J Orthod Dentofacial Orthop. 2003;124(6):651-655. https://doi.org/10.1016/s0889-5406(03)00621-8 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
12. Leonardi M, Armi P, Franchi L, Baccetti T. Two interceptive approaches to palatally displaced canines: a prospective longitudinal study. Angle Orthod. 2004;74(5):581-586. https://doi:10.1043/0003-3219(2004) 074<0581:TIATPD>2.0.CO;2. PubMed Google Scholar Scopus WoS
13. Baccetti T, Leonardi M, Armi P. A randomized clinical study of two interceptive approaches to palatally displaced canines. Eur J Orthod. 2008;30(4):381-385. https://doi.org/10.1093/ejo/cjn023 PubMed Full Text Links CrossRef Google Scholar ScopusWoS
14. Alessandri Bonetti G, Zanarini M, Danesi M, et al. Percentiles relative to maxillary permanent canine inclination by age: a radiologic study. Am J Orthod Dentofacial Orthop. 2009;136 (4):486 e481-486; discussion 486-487.https://doi.org/10.1016/j.ajodo.2009.01.022 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
15. Jung YH, Liang H, Benson BW, et al. The assessment of impacted maxillary canine position with panoramic radiography and cone beam CT. Dentomaxillo fac Radiol. 2012;41(5):356-360. https://doi.org/10.1259/dmfr/14055036 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
16. Mah JK, Danforth RA, Bumann A, Hatcher D. Radiation absorbed in maxillofacial imaging with a new dental computed tomography device. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2003;96(4):508-513. https://doi.org/10.1016/s1079-
2104(03)00350-0 Pubmed Full Text Links CrossRef Google Scholar Scopus WoS
17. The SEDENTEXCT Project. Radiation Protection: Cone Beam CT for Dental and Maxillofacial Radiology. Evidence Based Guidelines.
Luxembourg: European Commission; 2011:1-139.
18. Kau CH, Pan P, Gallerano RL, English JD. A novel 3D classification system for canine impactions–the KPG index. Int J
Med Robot. 2009;5(3):291-296. https://doi.org/10.1002/rcs.260 PubMed CrossRef Google Scholar Scopus WoS
19. Becker A, Chaushu G, Chaushu S. Analysis of failure in the treatment of impacted maxillary canines. Am J Orthod Dentofacial Orthop. 2010;137(6):743-754. https://doi.org/10.1016/j.ajodo.2008.07.022 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
20. Botticelli S, Verna C, Cattaneo PM, et al. Two- versus threedimensional imaging in subjects with unerupted maxillary canines. Eur J Orthod. 2011;33(4):344-349. https://doi.org/10.1093/ejo/cjq102 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
21. Alqerban A, Jacobs R, Fieuws S, Willems G. Comparison of two cone beam computed tomographic systems versus panoramic
imaging for localization of impacted maxillary canines and detection of root resorption. Eur J Orthod. 2011;33(1):93-102. https://doi.org/10.1093/ejo/cjq034 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
22. Roberts JA, Drage NA, Davies J, Thomas DW. Effective dose from beam CT examinations in dentistry. Br J Radiol. 2009;82(973):35-40. https://doi.org/10.1259/bjr/31419627 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
23. Shin HS, Nam KC, Park H, et al. Effective doses from panoramic radiography and CBCT (cone beam CT) using dose area product (DAP) in dentistry. Dentomaxillofac Radiol. 2014;43(5):20130439. https://doi.org/10.1259/dmfr.20130439 PubMed Full Text Links CrossRef Google Scholar WoS
24. Kadesjö N, Lynds R, Nilsson M, Shi XQ. Radiation dose from X-ray examinations of impacted canines: cone beam CT vs twodimensional imaging. Dentomaxillofac Radiol. 2018;47:20170305. https://doi.org/10.1259/dmfr.20170305 PubMed Full Text Links Google Scholar
25. Lee CYS, Koval TM, Suzuki JB. Low-dose radiation risks of computerized tomography and cone beam computerized tomography: Reducing the Fear and Controversy. J Oral Implantol. 2015; 41(5): e223–e230. https://doi.org/10.1563/AAIDJOI-D-13-00221 PubMed Full Text Links CrossRef Google Scholar Wos
26. Sonawane AU, Sunil Kumar JV, Singh M, Pradhan AS. Suggested diagnostic reference levels for paediatric X-ray examinations in India. Radiat Prot Dosimetry. 2011;147(3):423-428. https://doi.org/10.1093/rpd/ncq458 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
27. Kau CH, Lee JJ, Souccar NM. The validation of a novel index assessing canine impactions. Eur J Dent. 2013;7(4):399-404. https://doi.org/10.4103/1305-7456.120648 PubMed Full Text Links CrossRef Google Scholar Scopus
28. Dalessandri D, Migliorati M, Visconti L, et al. KPG index versus OPG measurements: a comparison between 3D and 2D methods in predicting treatment duration and difficulty level for patients with impacted maxillary canines. Biomed Res Int. 2014;2014:537620.https://doi.org/10.1155/2014/537620 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
29. Olive RJ. Factors influencing the non-surgical eruption of palatally impacted canines. Aust Orthod J. 2005;21(2):95-101. PubMed Google Scholar Scopus
30. Sosars P, Jakobsone G, Neimane L, Mukans M. Comparative analysis of panoramic radiography and cone-beam computed tomography in treatment planning of palatally displaced canines. Am J Orthod Dentofacial Orthop. 2020;157(5):719-727. doi: 10.1016/j.ajodo.2019.12.012. PubMed Full Text Links Google Scholar
31. Mohammed AK, Sravani G, Vallappareddy D, et al. Localization of impacted canines – a comparative study of computed tomography and orthopantomography. J Med Life. 2020;13(1):56-63. doi: 10.25122/jml-2020-0001.
PubMed Full Text Links Google Scholar
32. Wriedt S, Jaklin J, Al-Nawas B, Wehrbein H. Impacted upper canines: examination and treatment proposal based on 3D versus 2D diagnosis. J Orofac Orthop. 2012;73(1):28-40. https://doi.org/10.1007/s00056-011-0058-8 PubMed Full Text Links CrossRef Google Scholar Scopus
33. Pittayapat P, Willems G, Alqerban A, et al. Agreement between cone beam computed tomography images and panoramic radiographs for initial orthodontic evaluation. Oral Surg Oral Med Oral Pathol Oral Radiol. 2014;117(1):111-119.https://doi.org/10.1016/j.oooo.2013.10.016 PubMed Full Text Links CrossRef Google Scholar
34. Haney E, Gansky SA, et al. Comparative analysis of traditional radiographs and cone-beam computed tomography volumetric
images in the diagnosis and treatment planning of maxillary impacted canines. Am J Orthod Dentofacial Orthop. 2010;137
(5):590-597.https://doi.org/10.1016/j.ajodo.2008.06.035 PubMed Full Text Links CrossRef Google Scholar Scopus WoS
35. Serrant PS, McIntyre GT, Thomson DJ. Localization of ectopic maxillary canines — is CBCT more accurate than conventional
horizontal or vertical parallax? J Orthod. 2014;41(1):13-18.https://doi.org/10.1179/1465313313y.0000000076 PubMed CrossRef Google Scholar
Figures are shown in pdf document
| (read pdf) |