Principles of Dental Imaging RVT: Chapter 10 CTVT: pg. 1315- 1321

Objectives: Dental Imaging Describe the dental x-ray unit Explain the use of dental x-rays Understand the basics of dental film Explain the methods for dental film processing Know the differences between types of dental radiography

Why Dental Imaging? To see pathology below gingiva or inside tooth To evaluate missing teeth For client communication/education Medical/legal documentation Postoperative extraction confirmation Follow progression of pathology or periodontal disease Pre-purchase exams for show dogs

Why Do We Image Teeth? Periodontal disease is a common ailment in small animals. Isolating origin/extent without radiographs is difficult The x-ray shows lesions above AND below the gum line. Dental radiographs become part of your patient’s permanent medical record. Survey rads are good to have BEFORE disease process begins

When to Take Dental Radiographs Tooth mobility Gingival bleeding Nasal discharge Oral swelling Tooth is fractured Tooth is discolored Gingival recession/bone exposure is present Teeth are missing Prior to extraction - anatomical orientation and documentation Post extraction During endodontics

Dental Radiography: Overview Includes both intraoral and extraoral rads Special equipment not essential X-ray machine Dental x-ray machine Allows thorough evaluation of tooth & periodontium Remember what makes up the periodontium? Types of dental imaging: Film CR DR

Regular X-ray Machine Intraoral: Film inside the mouth Extraoral: Film outside the mouth Regular Machine - Intraoral Regular Machine - Extraoral

Dental Radiography Unit

Parts of a Dental Radiography Unit X-ray Tube Stationary anode Advantage? Disadvantage? No collimator light Can be angled directly over anatomy Extension cone (PID) Lead lined Variable lengths

Parts of a Dental Radiography Unit Generator/Control Panel Contains timer and kVp/mA regulators kVp usually pre-set around 70 mA usually pre-set at 7 or 8 Time is variable: set by operator Should have a technique chart near the generator Some systems have preset settings for dogs, cats, exotics

Radiation Safety - Dental Technician should stand behind a barrier whenever possible…however… Very minimal exposure to personnel when using dental machine Why is this? Never stand directly in front of or behind the tube head Film should never be held in patient’s mouth while radiograph is taken Dosimeters should be worn Machine should be inspected annually

Film Imaging Intraoral film is used in dental radiography Inexpensive, flexible, and provides good detail No intensifying screen Can achieve high definition with dental film due to infinite resolution Measured in line pairs/mm Requires higher technical factors Film is individually packaged No cassette or film box needed Store away from radiation!

Dental Film Individual dental films are packaged in a light-tight plastic envelope and contain: The film Paper folder/packing card Lead foil backing- prevents scatter radiation from affecting film Tab opening in back for film removal Packets are color-coded: Green: single film packet Gray: two-film packet

Dental Film Speeds D (ultra speed) E Used most commonly in veterinary dentistry E Twice as fast as D film Requires half the exposure

Dental Film Sizes used most often in small animal veterinary dentistry: Size 0 – Cats, exotics Size 2 (standard size) – Used most Size 4 – Larger teeth, occlusal surfaces

Film Dot Dental film is embossed with a raised dot in one of the corners. Convex side towards the beam (White side) Concave side away from the beam Dot is always positioned rostral.

Film Processing 1. Manual 2. Automatic Chairside darkroom Standard radiography processor Can be used by attaching dental film to leader film Film can become unattached and get lost…not ideal Dental processors are available! Efficient & consistent Work on roller transport system Usually not feasible unless large volume practice

Chairside Darkroom

Film Labeling & Storage Images are part of patient’s medical record Each image must be identified with permanent marker Store individually in mini envelopes Teeth must be identified correctly! Well-processed film is of good archival quality

Computerized Dental Radiography Image receptor is plastic covered, flexible phosphor plate Will need to be replaced over time Available in many sizes Processing requires a reader

Digital Dental Imaging Image receptor is a sensor pad that captures image and transfers it to a computer screen Sensor is not flexible and limited on sizes

CR and DR Imaging Recent in veterinary medicine (last 10 years or so) Advantages & disadvantages similar to non-dental radiography Can use the same x-ray unit as film Hand held units require more training May be cost-prohibitive (unless high volume)