Indian Journal of Comprehensive Dental CareRADI OGRAPHI C LOCALI ZATI ON OF I MPACTEDMAXI LLARY PERMANENT CANI NES: COMPARI SON OF TWO TECHNI QUESABSTRACTBackground:Exactlocalizationandearlydetectionofimpacted maxillary canine is necessary for interceptive treatment to reduce the needformorecomplexsurgicalandorthodonticintervention.The objective of localization is selection of a suitable technique which has minimal radiation dose, cost and maximum details. Aims: To evaluate the reliability of a single panoramic radiograph in locating the position of impacted maxillary canines. To compare two different radiographic techniques for localization of impacted maxillary canines: two periapical views using Clark's rule and single panoramic radiograph using technique suggested by Katsnelson et al.Materials and methods:Theinclinationoftheimpactedmaxillary canine to a horizontal line from the mesiobuccal cusps of the maxillary molarswasmeasuredonapanoramicradiograph.These measurements were used to predict the position of the tooth and compared with results of Clark's rule.o Results: The mean angulation of buccally impacted canines was 64.1 o o o(range 40to 95) and in the palatally impacted canines was 50.2 (range o o14.5 to 84). The location of impacted maxillary canine as measured on the panoramic radiograph was statistically significant.Conclusion:Panoramicradiographsareusefulforpredictingthe location of impacted maxillary canines when computed tomography is unavailable or unnecessary otherwise. Key words : impacted maxillary canines, panoramic radiograph, canine localization.1721. Kawar Randhawa2. Preeti Chawla3. Ramandeep S Narang 4. Adesh Manchanda Corresponding Author :Kawar Randhawa.MDS (Department of Oral Medicine, Diagnosis and Radiology)Address: Sri Guru RamDas Institute of Dental Sciences and Research, Amritsar.(M) 09872527749.e-mail: kawarr7@gmail.com1. Senior Lecturer, Department of Oral Medicine, Diagnosis and Radiology, Sri Guru Ram Das Institute of Dental Sciences and Research, Amritsar.2. Reader,DepartmentofOralMedicine,Diagnosisand Radiology, Sri Guru Ram Das Institute of Dental Sciences and Research, Amritsar.3. AssociateProfessor,DepartmentofOralPathologyand Microbiology,Sri Guru Ram Das Institute of Dental Sciences and Research, Amritsar.4. SeniorLecturer,DepartmentofOralPathologyand Microbiology, Sri Guru Ram Das Institute of Dental Sciences and Research, Amritsar.INTRODUCTION alveolus or labial, and the prevalence ratio of European: 1, 8Asian for a palatal position has been reported to be be 5:1. Maxillary canines are the second most impacted teeth after Peck et al. have stated that the etiology of palatally impacted third molars with a prevalence ranging from approximately 1,2,3canines is genetic in origin. The etiology of labially impacted 1%to 3%.Maxillary canine impaction is twice as common 94caninesisduetoaninadequatearchspace. Impacted infemalesasitisinmales. Theincidenceofcanine canines vary greatly in the inclination and location and can impaction in the maxilla is more than twice than that in the 5 lead to resorption of neighbouring incisors, as well as cystic mandible. Ofallpatientswhohaveimpactedmaxillary 6 degeneration.Theorthodontic-surgicalmanagementof canines, eight percent have bilateral impactions.impactedcaninesrequiresanaccuratediagnosisand Approximately one third of impacted maxillary canines are1localization of the impacted canine.7located labially and two-thirds are located palatally.In Asian subjects, however, the impacted canines were usually mid-Indian Journal of Comprehensive Dental CareJAN - JUNE 2012 VOL 2ISSUE 1I J C DC 173Indian Journal of Comprehensive Dental CareRadiographsareindicatedwhencaninebulgesarenotincompleterootformationandexistingorthodontic present; right and left canine development and eruption isappliance. For each subject, panoramic radiograph (using asymmetrical; occlusal development is advanced and thedigital panoramic Kodak 8000C machine) and two periapical lateral incisor is delayed in eruption, mal-positioned, or has aviews with different horizontal angulation were taken.pronounced labial or palatal inclination in relation to the Measurementsweredoneonpanoramicradiograph 2 adjacent central incisor. Accurate radiographs are critical for according to the method suggested by Katsnelson et al.The determiningthepositionofimpactedcaninesandtheir anatomic measure was the angulation of the canine to the relationtoadjacentteeth,assessingthehealthofthe occlusalplaneaccordingtothepanoramicradiograph.A neighbouring roots and determining the prognosis and best horizontal line was drawn from the mesiobuccal cusp tip of 10mode of treatment.the right and left maxillary first molars, and along the long Historically,severalradiographictechniqueshavebeenaxis of the impacted canines. The inclination of the canine as recommended, including periapical, occlusal, panoramic andmeasured lateral to the midline was recorded in degrees. For cephalometricradiographs,oracombinationoftheseunilateralimpactions,oneanglewasrecordedandfor 3approaches. When using these techniques, however, thebilateralimpactions,theangulationsofbothteethwere appearance of the longitudinal axis and the relationship withrecorded. The primary outcome variable was the location of theneighbouringbonyanddentalstructuresareoftenthe impacted canine, which would be closer to the buccal inaccurate because these complex structures overlap in thecortex(buccallyimpacted)orpalatalcortex(palatally maxillofacial region. In such cases, therefore, several authorsimpacted). (Fig. 1)haveusedcomputedtomography(CT)particularlyspiral 1CTfor localization of the impactions.11EricsonandKurolfoundthatperiapicalradiographs allowed accurate location of the teeth in 92%of the cases they evaluated. Although periapical films are diagnostic for transverse position, occlusal radiographs are more accurate for determining the positions of the canines relative to the midline. Lateral cephalometric radiographs are also helpful in assessingtheanteriorposteriorpositionofthedisplaced tooth, as well as its inclination and vertical location in the 10alveolus. Itwouldbeadvantageoustousepanoramic radiographs in localizing impacted maxillary canines as it is the most commonly recommended screening radiograph, Location of each impacted canine was also predicted on thedeliversrelativelylessradiation,easytoperform,cost-12basisoftwointraoralperiapicalviewsusingprincipleofeffectiveandreadilyavailable. Apanoramicradiograph parallaxfirstintroducedbyClark(1909).Itinvolvestwotaken in conjunction with 2 periapical views obtained using oradiographstakenatdifferenthorizontalangleswiththeClark's Rule (Buccal Object Rule) or a 60 maxillary occlusal same vertical angulation. Due to parallax, the more distantfilm allows the impacted teeth to be located either palatally 10object appears to travel in the same direction as the tube or buccally relative to adjacent teeth.shift and the object closer to the tube appears to move in the AIMSAND OBJECTIVES13opposite direction [same lingual opposite buccal (SLOB)]. This study was designed to evaluate the reliability of a single The result obtained using both the techniques were then panoramic radiograph in localization of impacted permanent compared using Cohen's Kappa statistics.maxillarycaninebyapplyingthecriteriasuggestedby RESULTS Katsnelson et al. and by comparing the results with those predicted by two periapical views using Clark's rule.Out of 32 patients, 20 (62.5%) were females and 12 (37.5%) were males. 8 patients had bilaterally impacted maxillaryMATERIALSAND METHODScanines. Of the 40 canines, 16 (40%) were on the right and 24 Thestudysubjectswithimpactedmaxillarycaninewere (60%) were on the left. Based on Clark's rule, out of 40 teeth, selectedfromoutpatientsvisitingDepartmentofOral 16 (40%) were buccally located and 24 (60%) were found to Medicine and Radiology, Sri Guru Ram Das Institute Of Dental be palatally placed. The mean angulation of the canines in Sciences & Research, Amritsar . The subjects ranged in age the buccal group as measured on the panoramic radiograph from 12.3 to 34.6 years (mean 16.9 5.8 years). Exclusion oooowas 64.1 (range 40to 95 ) and in the palatal group was 50.2criteriaincludedpresenceofcraniofacialanomalies, oo(range 14.5to 84 ). Figure 1: Measurement of angle on panoramic radiograph 174Indian Journal of Comprehensive Dental Carepalatally placed canine is 68.75%and 75%respectively. Table 3 suggests that there is moderate agreement between the techniques used in the study as suggested by Kappa value of 0.43. However the positions predicted by single panoramic radiograph are statistically significant (p