|Year : 2018 | Volume
| Issue : 2 | Page : 85-88
CBCT: A swap to conventional orthodontic imaging
G Sunil, Raghu R. S. V. M Ram, I Ranganayakulu
Department of Orthodontics and Dentofacial Orthopedics, GSL Dental College and Hospital, Rajahmundry, Andhra Pradesh, India
|Date of Web Publication||6-Jun-2018|
Dr. G Sunil
Department of Orthodontics and Dentofacial Orthopedics, GSL Dental College and Hospital, Rajahmundry – 533296, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Conventional imaging techniques are essentially two-dimensional representations of three-dimensional objects and suffer from several restrains. Cone-beam computed tomography (CBCT), a world shattering revolution, offered a unique platform for orthodontic diagnosis and treatment planning. The aim of this article is to provide a broad overview of applications of CBCT in orthodontia.
Keywords: CBCT, diagnosis and treatment planning, orthodontia
|How to cite this article:|
Sunil G, Ram RR, Ranganayakulu I. CBCT: A swap to conventional orthodontic imaging. J NTR Univ Health Sci 2018;7:85-8
| Introduction|| |
Imaging of craniofacial complex is an integral part of orthodontic diagnosis and treatment planning. Conventional imaging techniques are essentially two-dimensional (2D) representations of three-dimensional (3D) structures. The advent of cone-beam computed tomography (CBCT) has gained considerable applause universally in contemporary era as a viable 3D imaging modality. This brought a true paradigm shift with its multiple applications in orthodontia. This article discusses the applicatory uses of CBCT in various orthodontic tasks, from simple to more advance, and insight into the future of high-tech treatments.
| Applications of Cone-Beam Computed Tomography in Orthodontics|| |
CBCT reconstructed lateral cephalogram can be generated so that conventional measurements can be made and compared with the existing 2D norms. They offer the advantage to digitally reorient the head position in cases in which a patient does not undergo scanning with proper head position. CBCT scans give more accurate measurements when compared with cephalometric radiographs of CBCT and conventional radiographs. Image quality can also be enhanced by virtually sculpturing away extraneous superimposing skeletal structures. The frequency of highly reliable values is greater for CBCT multiplanar than 3D reconstructions. In addition, separate images can be created of the left and right sides for assessment of symmetries.
Localization of impacted and transposed teeth
CBCT is a vital tool to locate the exact position and the condition of impacted and transposed tooth. It has shown that enhanced precision in localization (palatal versus labial), improved estimations of space conditions in the arch, and more exact angulation , of canine teeth can be obtained with CBCT. These 3D images are beneficial in determining the proximity of adjacent incisor and premolar roots, which can be invaluable in determining the ease of uncovering and bonding. It also helps in deciding the vector of force that should be used to move the tooth into the arch with a lesser chance of adjacent root resorption.
CBCT scans can be used to reliably assess cervical vertebrae maturity, which provides for a consistent evaluation of skeletal maturity. The estimate of maturation stages of cervical vertebrae on CBCT provides a reliable evaluation of pubertal growth support and strongly positive correlations with lateral cephalograms and hand–wrist radiographs.
Temporomandibular joint evaluation
CBCT is indicated for orthodontic cases that require analysis of temporomandibular joint (TMJ) bone components accompanied by signs and symptoms., One of the greatest advantages of CT scan is evaluating the condyle–disk relationship, condylar erosions,, condylar changes after orthodontic treatment, volumetric evaluation of TMJ, and effects of distraction splint therapy in mandibular asymmetry cases.
Evaluation of airways
Advent of CBCT lead to a major improvement in airway analysis, allowing for its 3D and volumetric analyses enabling in diagnosis and management of complex clinical conditions such as sleep apnea and enlarged adenoids.
Patients with cleft lip and cleft palate
CBCT for patients with cleft lip and palate is an useful aid for both preoperative and therapeutic evaluations. Estimates of the size (dimensions) of osseous defects and spatial relationship of the defect with other important anatomic structures are difficult to obtain in 2D images. CBCT can provide the cleft's exact anatomic relationships and bone thickness around the existing teeth in proximity to the cleft or clefts. This information is invaluable for grafting procedures planned and for possible tooth movement in the existing dentition.
| Temporary Anchorage Devices (Miniscrew Implants)|| |
The successful placement of temporary anchorage devices (TADs) can be greatly enhanced by the information derived from CBCT imaging. 3D scans are especially useful in evaluating the amount and quality of bone available in the desired site of placement. Surgical guides developed using CBCT scans and rapid prototyping have aided in accurate placement of TADs. Thus, CBCT images help place the miniscrew implants in safe zones. Finite element analysis constructed using CBCT provides insight into advantages or disadvantages of orthodontic appliances with TADs by simulating stress distribution.
| Rapid Maxillary Expansion|| |
CBCT images provide an invaluable resource for assessing the effect of rapid maxillary expansion (RME). While all studies on rapid palatal expansion treatment demonstrated both dental and alveolar tipping, none found detrimental effects (such as dehiscence or fenestrations) to the alveolar bone supporting posterior teeth. CBCT is a reliable diagnostic tool for prediction of mid-palatal suture maturation  and planning surgically assisted rapid maxillary expansion (SARME) in skeletally mature patients.
| External Apical Root Resorption|| |
CBCT can potentially provide improved visualization of roots, thereby making it a valuable method for evaluating preorthodontic or postorthodontic root resorption. In a meta-analysis, CBCT is superior to periapical radiographs in accuracy of diagnosing external root resorption. They emphasized that periapical radiographs provide limited information of external root resorption in buccal and lingual root surface. CBCT is also a good method for assessing alveolar bone height, yet is associated with a high number of false-positives in the detection of fenestrations. It provides a significant advantage over conventional radiographs for periodontal assessment since it allows buccal and lingual defects to be measured, as well as interproximal defects.
| Planning of Orthognathic Surgery|| |
The distinctive and anticipated changes subsequent to a surgery are depicted very easily through a CBCT than in comparison to cumbersome computer modeling. The virtual anatomical models customized by CT volumes are configured with the available 3D image data present. The generated models are then used for various treatment considerations and to create a virtual image of the tissues and their response to development, treatment, and function.
| Root Angulations in Posttreatment Orthodontics|| |
Bouwens et al. compared mesiodistal root angulation with posttreatment panoramic radiographs and CBCT and concluded that panoramic radiographs are less reliable than CBCT regarding the idea of mesiodistal tooth angulations and might exhibit deviations in both mesial and distal directions for all teeth.
| Superimpositions|| |
The introduction of CBCT allows clinicians to perform superimpositions in three-dimensions and has eliminated some of the errors that occur with traditional lateral cephalometric superimposition. These 3D superimpositions help in better assessment of treatment outcomes. Studies of surgical treatment outcome may be facilitated using a new superimposition method which enables the operator to superimpose a custom surface mesh of the first CBCT image onto a second CBCT image of the anterior cranial base. CBCT volume-derived virtual facial models evaluate postsurgical changes in the soft tissue overlying the mandible in response to mandibular advancement surgery. They superimposed the virtual models at the cranial base and used color maps to qualitatively evaluate surgical and postsurgical changes.
| Virtual Models|| |
CBCT data can be used to produce 3D digital study models without the need for alginate impressions. It avoids patient discomfort and saves orthodontist's valuable chair time. These models are of higher diagnostic value than other digital models because it includes not only tooth crowns but also roots, impactions, developing teeth, and alveolar bone.,
| Indirect Bonding of Brackets|| |
Construction of “hardcopy” models from CBCT image can be used for laboratory procedures required for indirect bonding.
| Custom-Made Brackets and Wires|| |
The fabrication of custom lingual orthodontic appliances has been demonstrated using CBCT image data with existing technology to virtually plan a patient's treatment and the manufacturing of custom appliances with 3D printing technology. Such advances appear to be rapid, and they also promise efficient and effective patient-specific treatments.
| Tooth–bone Relationship|| |
In bimaxillary protrusion cases, Class III patients with an initial symphysis bone width, and cases with preexisting periodontal disease, after maxillary expansion treatment, CBCT provides valuable information about tooth–bone relationships, and it might reduce the risk factor for dehiscence.
| Dentofacial Orthopedics|| |
CBCT is used for evaluating treatment outcomes for growing patients by 3D overlays of superimposed models and 3D color-coded displacement maps providing visual and quantitative assessments of growth and treatment changes. CBCT scans were able to identify maxillary and mandibular positional changes and bone remodeling relative to the anterior cranial fossa.
| Investigation of Orthodontic-Associated Sensory Disturbances|| |
Sensory disturbances of the lower lip and chin area are commonly reported after orthognathic surgery, after dentoalveolar surgery following endodontic treatment, or following removal of the mandibular third molars. In contrast, reports of sensory disturbances occurring secondary to regular orthodontic treatment are extremely rare. However, when they do occur, they can only be diagnosed by CBCT. These neural disturbances that occur during orthodontic treatment are classified as neuropraxias and they usually result from temporary conduction blockade due to compression of the inferior alveolar nerve bundle. Orthodontic treatment-induced transient mental nerve paresthesia demonstrated the importance of CBCT scans as the sole aid in obtaining a definitive diagnosis of this clinical condition.
| Posttreatment Temporomandibular Disorders|| |
By providing concurrent visualization of TMJs and maxillomandibular spatial relationships and occlusion, CBCT images provide clinicians with the opportunity to visualize and measure the local and regional effects associated with TMJ abnormalities. Similarly, cases involving centric occlusion versus centric relation (CO/CR) discrepancies, unilateral Class II of TMJ in CO versus CR, and additional diagnostic information derived from CBCT scans would be beneficial in these cases.
| Conclusion|| |
In recent years, the use of CBCT in orthodontics has gained popularity and is preferred as an imaging method by many clinicians for diagnosis, treatment planning, and treatment outcome. It is particularly important in cases where conventional radiography cannot provide adequate diagnostic information. Hence, CBCT is the future of orthodontics and applications in orthodontics seem almost limitless.
Source of Support
Conflicts of Interest
There are no conflicts of interest.
| References|| |
Van Vlijmen OJ, Bergeг SJ, Swennen GR, Bronkhorst EM, Katsaros C, Kuijpers-Jagtman AM. Comparison of cephalometric radiographs obtained from cone-beam computed tomography scans and conventional radiographs. J Oral Maxillofac Surg 2009;67:92-7.
Neiva MB, Soares ÁC, Lisboa Cde O, Vilella Ode V, Motta AT. Evaluation of cephalometric landmark identification on CBCT multiplanar and 3D reconstructions. Angle Orthod 2015;85:11-7.
Walker L, Enciso R, Mah J. Three-dimensional localization of maxillary canines with cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2005;128:418-23.
Chaushu S, Chaushu G, Becker A. The role of digital volume tomography in the imaging of impacted teeth. World J Orthod 2004;5:120-32.
Haney E, Gansky SA, Lee JS, Johnson E, Maki K, Miller AJ, 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;137:590-7.
Ericson S, Kurol J. Resorption of maxillary lateral incisors caused by ectopic eruption of the canines. A clinical and radiographic analysis of predisposing factors. Am J Orthod Dentofacial Orthop 1988;94:503-13.
Shim JJ, Heo G, Lagravère MO. Assessment of skeletal maturation based on cervical vertebrae in CBCT. Int Orthod 2012;10:351-62.
American Academy of Oral and Maxillofacial Radiology. Clinical recommendations regarding use of cone beam computed tomography in Orthodontics. Position statement by the American Academy of Oral and Maxillofacial Radiology. Oral Surg Oral Med Oral Pathol Oral Radiol Endodontol 2013;116:238-57.
Scarfe WC, Farman AG. What is cone-beam CT and how does it work? Dent Clin N
Okeson JP. Management of Temporomandibular Disorders and Occlusion. Mosby Co.; 1998. p. 281-303.
Honey O, Scarfe W, Hilgers M, Klueber K, Silveira AM, Haskell BS, et al
. Accuracy of the cone-beam computed tomography imaging of the temporomandibular joint: Comparisons with panoramic radiology and linear tomography. Am J Orthod Dentofacial Orthop 2007;132:429-38.
Tsiklakis K, Syriopoulos K, Stamatakis H. Radiographic examination of temporomandibular joint using cone beam computed tomography. Dentomaxillofacial Radiol 2004;33:196-201.
Sforza E, Bacon W, Weiss T, Thibault A, Petiau C, Krieger J. Upper airway collapsibility and cephalometric variables in patients with obstructive sleep apnea. Am J Respir Crit Care Med 2000;161(pt 1):347-52.
Hamada Y, Kondoh T, Noguchi K, Iino M, Isono H, Ishii H, et al
. Application of cone beam computed tomography to clinical assessment of alveolar bone grafting: A preliminary report. Cleft Palate Craniofac J 2005;42:128-37.
Lund H, Gröndahl K, Gröndahl HG. Cone beam computed tomography for assessment of root length and marginal bone level during orthodontic treatment. Angle Orthod 2010;80:466-73.
Jang HI, Kim SC, Chae JM, Kang KH, Cho JW, Chang NY, et al
. Relationship between maturation indices and morphology of the midpalatal suture obtained using cone-beam computed tomography images. Korean J Orthod 2016;46:345-55.
Schendel SA, Lane C, Harrell WE Jr. 3D orthognathic surgery simulation using image fusion. Semin Orthod 2009;15:48-56.
Bouwens DG, Cevidanes L, Ludlow JB, Phillips C. Comparison of mesiodistal root angulation with posttreatment panoramic radiographs and cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2011;139:126-32.
Mah J. The evolution of digital study models. J Clin Orthod 2007;4:557-61.
Kau CH, Littlefield J, Rainy N, Nguyen JT, Creed B. Evaluation of CBCT digital models and traditional models using Little's index. Angle Orthod 2010;80:435-9.
Hechler SL. Cone beam CT: Applications in orthodontics, Dent Clin N