Case Report Cone Beam CT in Diagnosis and Surgical Planning of Dentigerous Cyst Naira Figueiredo Deana 1 and Nilton Alves 2,3 1 Magister Program in Dentistry, Faculty of Dentistry, Universidad de La Frontera, Temuco, Chile 2 CIMA-Research Center in Applied Morphology, Universidad de La Frontera, Temuco, Chile 3 Faculty of Dentistry, Universidad de La Frontera, 1145 Francisco Salazar Avenue, P.O. Box 54-D, Temuco, Chile Correspondence should be addressed to Nilton Alves; niltonnalves@yahoo.com.br Received 25 October 2016; Revised 6 January 2017; Accepted 15 January 2017; Published 15 February 2017 Academic Editor: Daniel Torr´ es-Lagares Copyright © 2017 Naira Figueiredo Deana and Nilton Alves. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Diagnosis and preoperative planning are critical in the execution of any surgical procedure. Panoramic radiography is a routine method used in dentistry to assist clinical diagnosis; however, with this technique 3D anatomical structures are compressed into 2D images, resulting in overlapping of structures which are of interest in the diagnosis. In this study we report the case of a patient who presented with a dentigerous cyst of expressive dimensions in the body of the mandible region. Te surgery was planned and executed afer observing the margins of the lesion by Cone Beam Computed Tomography (CBCT). We conclude that CBCT is a precise method to help diagnosis; it provides greater accuracy in surgical treatment planning through 3D image display, allowing more efective results. 1. Introduction Te dentigerous (or follicular) cyst (DC) is the second most common type of dental cyst and the most common in jaw development [1]. Benn and Altini [2] propose the existence of two types of dentigerous cysts: one of a developing nature and the other infammatory. From a clinical point of view, dentigerous cysts are generally asymptomatic, slow-growing, associated with the crown of an impacted or unerupted permanent tooth, and characterised by retarded eruption of the tooth [1]. However they may grow large enough to cause destruction of the cortical bone, resulting in fuctuation, spontaneous pain, exudation, and rapid development of the pathology, which are signs of acute infammation round the margins of the cyst [3]. Diagnosis of the lesion should not be based on X-ray evidence alone, but also on clinical evidence, particularly microscopic examination of the sample [2]. Periapical and panoramic X-rays are the most commonly used imaging examinations in dentistry for diagnosis and surgical planning. However the information acquired in these examinations is limited, since the three-dimensional anatomy of the area X-rayed is shown in two dimensions, with superimposed planes. Although these methods produce acceptable images in the mesiodistal direction, observation in the vestibulolingual direction is difcult. Tere may also be geometrical distortion of the structures X-rayed when we use these imaging methods [4]. A very efcient imaging technique for diagnosing DC is Magnetic Resonance Imaging (MRI), since it allows cysts to be distinguished from tumoral lesions [5], ensuring safe, efcient performance [6]; however MRI is a very high-cost examination with limited availability, making it impractical for routine clinical use. In the last decade a new technology—Cone Beam Com- puterised Tomography (CBCT)—has ofered dental surgeons three-dimensional reproduction of images of mineralised maxillofacial tissues, with minimum distortion and sig- nifcantly lower doses of radiation than conventional CT [7]. Te object of this study was to report a clinical case of a dentigerous cyst in which the diagnostic hypothesis and the decision on the treatment plan were based on CBCT. Hindawi Case Reports in Dentistry Volume 2017, Article ID 7956041, 6 pages https://doi.org/10.1155/2017/7956041