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Dental radiography

Introduction

Dental radiography is, typically, limited to four types of examinations including: 1) intraoral radiographs; 2) panoramic radiographs; 3) cephalometric radiographs; and 4) cone-beam CT imaging. Intraoral radiography results in the most dental radiographs and the highest radiation dose to the patient. Panoramic radiographs, a tomographic image of all of the teeth and jaw, result in a relatively low dose, with much lower volume of images being produced. Cephalometric images are primarily lateral radiographs of the head used for orthodontic measurement purposes. Cone-beam CT is used usually for treatment planning before placing dental implants.

Important Principles

Dental radiography is a relatively simple procedure. Intraoral x-ray generators usually are fixed kilovoltage (70 kVp) and tube current (on the order of 7 mA). Likewise, panoramic systems also use fixed techniques factors, including fixed exposure time.

Two speeds of film (D and F Speed) are available with the F-speed film reducing patient dose by a factor of two. Dentists should be encouraged to use the F-speed film since the image quality is the same as D-speed film and an F-speed film costs only a few cents more than a D-speed film.
Digital radiography is experiencing a growing acceptance in the dental community, with about 25% of the dental facilities in the U.S. using digital imaging in 2009.

Photographic processing is a problematic area for dental radiography. Radiation doses that are three to four times that needed to produce a quality image are often seen, mostly as a result of less than optimal film processing due to depleted photographic developer, low processing temperatures, or contaminated solutions.

Introduction to References

White and Pharoah provide an excellent background covering the physics of dental radiography as well as the basics of dental image interpretation. Several excellent quality control publications are provided in the Quality Control References.