Introduction: Oral and Maxillofacial Imaging: Evolving Technologies and Paradigm Shifts

Sanjay M. Mallya, BDS, MDS, PhD, is an associate professor and the chair of oral and maxillofacial radiology at the University of California, Los Angeles, School of Dentistry. He has authored numerous scientific manuscripts and book chapters on oral radiology, periodontology, endodontology and implantology. He is the editor of “White and Pharoah’s Oral Radiology” and is a past president of the American Academy of Oral and Maxillofacial Radiology. Dr. Mallya is a diplomate of the American Board of Oral and Maxillofacial Radiology and serves on the board of the Intersocietal Accreditation Commission. Conflict of Interest Disclosure: None reported.

The first digital sensor for intraoral imaging was introduced in 1989.[1] Over the last 32 years, digital imaging has become the predominant technology used for intraoral imaging (~86%) and panoramic imaging (~82%) in the United States.[2] Currently, dentists have a vast selection of digital imaging systems available from several vendors that include options for intraoral, panoramic and cephalometric imaging. These systems can be broadly divided into two technologies: complementary metal oxide semiconductor (CMOS)-based sensors and photostimulable phosphors (PSP).[3] The image quality achievable with these digital receptors varies with the specific vendor product used[4] — and this should be an important consideration for dentists seeking a digital imaging system for their practice. Equally important, dentists who purchase digital systems must ensure that the system is functioning as expected, with no deterioration of image quality over time. Contributors to the image quality include the X-ray source, the selected hardware components (sensor or PSP plate and reader), the software used to display and adjust the image appearance and the specifications of the computer monitor used to present the image to the dental team. Additionally, the ambient light conditions of the viewing environment may also impact image perception, adding another factor for consideration. Recognizing that dental practices need straightforward guidance and direction to navigate through these factors, the ADA Standards Committee on Dental Informatics (SCDI) drafted and approved the ANSI/ADA Standard No. 1094 for Quality Assurance for Digital Intraoral Radiographic Systems.[5] This document, the first of a series of documents addressing digital image quality control, outlines methods that the dental team can use to periodically confirm continued and expected performance of digital intraoral radiographic systems. The article by Dr. Peter Mah, Dr. Allison Buchanan and Dr. (Col) Teresa E. Reeves provides the first introduction to this standard. The information in this article discusses parameters of image quality and processes of digital image quality assurance and aims to make the reader an educated consumer and skillful user of digital imaging.

Digital imaging technology, in particular CMOS-based imaging, allows us to make diagnostically adequate images with lower radiation than used for X-ray film. It is estimated that 382 million intraoral radiologic examinations are performed annually in the U.S.2 Approximately 20% of these examinations are performed on children, a group known to be more sensitive to radiation-induced cancer. The scope of imaging in dentistry has also expanded, driven by the availability of in-office cone beam computed tomography (CBCT) imaging. An estimated 5.2 million CBCT examinations are done in the U.S., with approximately 28% of these examinations performed on children.2 The increasing use of computed tomography (CT) in health care, including dentistry, raised concerns for indiscriminate and unnecessary radiation exposure.[6,7] This prompted responses from the profession leading to guidance for safety in imaging and establishing dose reference levels and from the vendors who incorporated dose reduction methods such as automatic exposure control in CT imaging. The article on safe and effective use of imaging emphasizes appropriate selection of patients for imaging as an essential step in radiation safety. The article informs the reader on the nature of diagnostic radiation’s effects and magnitude and, importantly, approaches to convey this information to patients in lay language.

The availability of in-office CT imaging has markedly expanded the scope of imaging in dentistry. CT allows us to better view anatomy free of superimposition and distortion. CT data is combined with other sources of digital information, such as optical scans, to fabricate surgical guides for implant planning. Importantly, the application of limited field of view (FOV) CBCT has markedly enhanced our ability to diagnose and manage diseases of the pulp and periapical tissues.[8,9] To facilitate the effective use of CBCT imaging in dentistry, the American Association of Endodontists (AAE) and the American Academy of Oral and Maxillofacial Radiology (AAOMR) have developed guidelines that help clinicians identify those situations where CBCT imaging is likely to provide beneficial information.[10] The article by Dr. Rumpa Ganguly and Dr. Mike Sabeti addresses the recommendations via a casebased presentation of clinical situations and the anticipated value of CBCT imaging. Readers of this article should identify that appropriate patient selection maximizes diagnostic yield and eliminates indiscriminate radiation exposure, underscoring that eventual implementation of effective and safe use of this technology lies in the hands of the end user.

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