Role of CBCT in diagnosis and treatment plan of Impacted teeth : A Case Report

In recent years Cone Beam Computed Tomography (CBCT) has become a widely accepted radiographic tool for diagnosis, treatment planning and follow-up in dentistry. 3D imaging has improved diagnostic efficiency and the practice of dentistry in a variety of ways; from routine evaluation to complex analysis of unusual pathology and congenital deformities. The technology available today makes dentistry better, easier, and more accurate. The most recognized need for CBCT imaging in orthodontics is that of the impacted canine evaluation. This article reports a patient having impacted right maxillary lateral incisor and canine; which is evaluated by 3D CBCT and was found beneficial particularly in terms of anatomical detail of root resorption and labiolingual relationships of the impacted tooth with the roots of neighboring teeth. Linear and angular measurements on CBCT images were accurate and helped in determining the exact location of the impacted teeth making it convenient for the surgical exposure of impacted teeth.


INTRODUCTION
[8][9] A CBCT scan with a single revolution of the radiation source is sufficient to scan the entire maxillofacial region (Sukovic et al, 2001). 10CBCT technology is based on the use of a cone-shaped X-ray beam that is directed through the patient and the remnant beam is captured on a flat two-dimensional (2D) detector (Scarfe et al, 2006). 11The X-ray source and detector are able to revolve about a patient's head, and a sequence of two-dimensional (2D) images is generated.These 2D images are then converted into a three-dimensional (3D) image using computer software.When comparing conventional radiography and CBCT.Katheria et al found that CBCT provides more information regarding the location of pathology, the presence of root resorption, and treatment planning. 12The rapid development of CBCT scanning combined with 3D rendering techniques produce high resolution images that have been proven to be useful for the diagnosis of impacted canines, treatment planning, and the identification of associated complications, such as root resorption, in adjacent incisors. 13[15] Dr Darpa Pradhan, 1 Dr Tang Tian 2

ABSTRACT
In recent years Cone Beam Computed Tomography (CBCT) has become a widely accepted radiographic tool for diagnosis, treatment planning and follow-up in dentistry.3D imaging has improved diagnostic efficiency and the practice of dentistry in a variety of ways; from routine evaluation to complex analysis of unusual pathology and congenital deformities.The technology available today makes dentistry better, easier, and more accurate.The most recognized need for CBCT imaging in orthodontics is that of the impacted canine evaluation.
This article reports a patient having impacted right maxillary lateral incisor and canine; which is evaluated by 3D CBCT and was found beneficial particularly in terms of anatomical detail of root resorption and labiolingual relationships of the impacted tooth with the roots of neighboring teeth.Linear and angular measurements on CBCT images were accurate and helped in determining the exact location of the impacted teeth making it convenient for the surgical exposure of impacted teeth.In this case, CBCT was helpful in locating the exact position of the impacted teeth and their relation with the adjacent teeth which helped to access and determine the direction of orthodontic forces.Furthermore, with proper treatment planning, minimal bone structures were removed to expose the impacted teeth, which helped in rapid healing and new bone formation.Figure 5 shows surgical extrusion in progress.

DISCUSSION
Proper diagnosis is required for successful treatment.
Traditional 2D radiographs like Panaromic view is used to evaluate the vertical position, occlusal X-ray to evaluate the proximity to adjacent teeth, and periapical radiographs to determine the labiopalatal position.
However volumetric images are obtained from a CBCT scan. 16Haney et al showed enhanced precision in the localization of canine teeth and improved estimation of the space conditions in the arch obtained with CBCT.This can greatly affect diagnosis and treatment planning to facilitate a more clinically-orientated approach. 17iedt et al 18 stated that CBCT should be used as an adjuvant for routine panoramic radiographs in the following cases: 1. Canine inclination in the panoramic X-ray exceeding 30°2 . Root resorption of adjacent teeth is suspected, and/or 3. Canine apex is not clearly discernible in the panoramic X-ray, implying dilacerations of the canine root.
CBCT provides highly detailed 3D imaging with a single x-ray exposure of approximately 18 seconds.Imaging can be obtained at any angle, thus offering optimum viewing and eliminating superimpositions.CBCT images have provided reliable data on root angulation 19 and the management of impacted canines. 20,21The diagnostic

CONCLUSION
The qualitative assessment of external apical root resorption reveals clinically considerable amount of root resorption in stainless steel boot loop group which can be attributed to higher force delivery by stainless steel loop which accounts to the inherent property of the materials used for retraction.

Figure 1 :Figure 2 :Figure 3 :
Figure 1: 3D CBCT images showing the impacted 13, 33 and 43. A. Frontal view of skull.B. Lateral view of skull.C. Postero Anterior (P.A) view of skull.D. Sagittal slices that were used to identify the exact location of impacted canine and the amount of root resorption on the adjacent tooth (13-upper right permanent canine, 33-Lower left permanent canine, 43-lower right permanent canine)

Figure 4 :Figure 5 :
Figure 4: 3D CBCT images showing the presence of two supernumerary teeth along with the position of impacted 12 and 13, proximity of impacted teeth with the adjacent teeth (12-upper right lateral, 13-upper right canine) (A.Right oblique view, B. Position of impacted lateral and canine when 3D image is rotated, C. Sagittal slices, D. Axial view)