Cone-beam computed tomography (CBCT) systems have been designed for imaging hard tissues of the maxillofacial region. CBCT is capable of providing sub-millimetre resolution in images of high diagnostic quality, with short scanning times (10-70 seconds) and radiation dosages reportedly up to 15 times lower than those of conventional CT scans. Increasing availability of this technology provides the dental clinician with an imaging modality capable of providing a 3-dimensional representation of the maxillofacial skeleton with minimal distortion. This article provides an overview of currently available maxillofacial CBCT systems and reviews the specific application of various CBCT display modes to clinical dental practice.

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Clinical applications of cone-beam computed tomography in dental practice.

Objectives: Cone beam computed tomography (CBCT), which provides a lower dose, lower cost alternative to conventional CT, is being used with increasing frequency in the practice of oral and maxillofacial radiology. This study provides comparative measurements of effective dose for three commercially available, large (12″) field-of-view (FOV), CBCT units: CB Mercuray, NewTom 3G and i-CAT. Methods: Thermoluminescent dosemeters (TLDs) were placed at 24 sites throughout the layers of the head and neck of a tissue-equivalent human skull RANDO phantom. Depending on availability, the 12″ FOV and smaller FOV scanning modes were used with similar phantom positioning geometry for each CBCT unit. Radiation weighted doses to individual organs were summed using 1990 (E1990) and proposed 2005 (E2005 draft) ICRP tissue weighting factors to calculate two measures of whole-body effective dose. Dose as a multiple of a representative panoramic radiography dose was also calculated. Results: For repeated runs dosimetry was ge...

/pdf/dosimetry-of-3-cbct-devices-for-oral-and-maxillofacial-3pq1k8mr17.pdf

Dosimetry of 3 CBCT devices for oral and maxillofacial radiology: CB Mercuray, NewTom 3G and i-CAT

Objectives This study compares 2 measures of effective dose, E1990 and E2007, for 8 dentoalveolar and maxillofacial cone-beam computerized tomography (CBCT) units and a 64-slice multidetector CT (MDCT) unit. Study design Average tissue-absorbed dose, equivalent dose, and effective dose were calculated using thermoluminescent dosimeter chips in a radiation analog dosimetry phantom. Effective doses were derived using 1990 and the superseding 2007 International Commission on Radiological Protection (ICRP) recommendations. Results Large-field of view (FOV) CBCT E2007 ranged from 68 to 1,073 μSv. Medium-FOV CBCT E2007 ranged from 69 to 560 μSv, whereas a similar-FOV MDCT produced 860 μSv. The E2007 calculations were 23% to 224% greater than E1990. Conclusions The 2007 recommendations of the ICRP, which include salivary glands, extrathoracic region, and oral mucosa in the calculation of effective dose, result in an upward reassessment of fatal cancer risk from oral and maxillofacial radiographic examinations. Dental CBCT can be recommended as a dose-sparing technique in comparison with alternative medical CT scans for common oral and maxillofacial radiographic imaging tasks.

/pdf/comparative-dosimetry-of-dental-cbct-devices-and-64-slice-ct-omz4if0pfp.pdf

Comparative dosimetry of dental CBCT devices and 64-slice CT for oral and maxillofacial radiology

http://www.endoexperience.com/documents/DeVos2009.pdf

Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: a systematic review of the literature.

Anthropometry of the head and face

Three-dimensional localization of maxillary canines with cone-beam computed tomography.

Objective The purpose of this investigation was to measure the tissue-absorbed dose and to calculate the effective dose for the NewTom 9000, a new generation of computed tomographic devices designed specifically for dental applications. Comparisons are made with existing reports on dose measurement and effective dose estimates for panoramic examinations and other computed tomographic imaging modalities for dental implants. Study design Thermoluminescent dosimeters were implanted in a tissue-equivalent humanoid phantom at anatomic sites of interest. Absorbed dose measurements were obtained after single and double exposures. The averaged tissue-absorbed doses were used for the calculation of the whole-body effective dose. Results The effective dose for imaging of maxillomandibular volume with a NewTom 9000 machine is 50.3 μSv. Conclusion The effective dose with the NewTom 9000 machine is significantly less than that achieved with other computed tomographic imaging methods and is within the range of traditional dental imaging modalities.

Radiation absorbed in maxillofacial imaging with a new dental computed tomography device.

Incidental findings in the maxillofacial area with 3-dimensional cone-beam imaging

Background Comprehensive visualization and records of the craniofacial complex have been goals in orthodontic imaging. These tasks have been performed by means of plaster, photographs and radiographs. These approaches have evolved across time, and cone-beam computed tomography (CBCT) has emerged as a comprehensive imaging modality for orthodontics. Methods The authors provide a practical guide for applying CBCT in orthodontics, with an emphasis on situations in which conventional imaging is limited. These situations include dental development, limits of tooth movement, airway assessment, craniofacial morphology and superimposition. Results Complexities of the craniofacial complex, dentition and airway present challenges in obtaining conventional images. CBCT has image-fidelity advantages over conventional imaging that can lead to improved visualization. Conclusions CBCT is changing orthodontics with respect to clinically assessing patients and is evolving with respect to diagnosis, clinical techniques and outcomes. Clinical Implications The clinical value proposition of CBCT is to describe craniofacial anatomy accurately and provide comprehensive information regarding anatomical relationships and individual patient findings for improved diagnosis, treatment planning and prognostication.

https://jada.ada.org/article/S0002-8177(14)63739-9/pdf

James Mah

Papers

Three-dimensional localization of maxillary canines with cone-beam computed tomography.

Radiation absorbed in maxillofacial imaging with a new dental computed tomography device.

Incidental findings in the maxillofacial area with 3-dimensional cone-beam imaging

Practical Applications of Cone-Beam Computed Tomography in Orthodontics

Three-dimensional craniofacial imaging.