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at dentalcare.com Continuing Education Course, December 9, 2014

Online Course: www.dentalcare.com/en-US/dental-education/continuing-education/ce462/ce462.aspx

Disclaimer: Participants must always be aware of the hazards of using limited knowledge in integrating new techniques or

procedures into their practice. Only sound evidence-based dentistry should be used in patient therapy.

Clinical errors occur as a consequence of improper patient preparation or management, technique and

exposure. Correct technique and proper patient management skills are essential to maximize the outcome

and the information obtained from digital radiographic images, while at the same time minimizing patient

radiation exposure. This course will provide an overview of digital imaging, a review of technique principles

and the identification and correction of common errors that occur in digital intraoral and panoramic imaging.

Conflict of Interest Disclosure Statement• The author reports no conflicts of interest associated with this work.

ADAAThis course is part of the home-study library of the American Dental Assistants

Association. To learn more about the ADAA and to receive a FREE e-membership

visit: www.dentalassistant.org

ADA CERPThe Procter & Gamble Company is an ADA CERP Recognized Provider.

ADA CERP is a service of the American Dental Association to assist dental professionals in identifying

quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses

or instructors, nor does it imply acceptance of credit hours by boards of dentistry.

Concerns or complaints about a CE provider may be directed to the

provider or to ADA CERP at: http://www.ada.org/cerp

Gail F. Williamson, RDH, MSContinuing Education Units: 4 hours

Digital Imaging Techniques and Error Correction

http://www.dentalcare.com/en-US/dental-education/continuing-education/ce462/ce462.aspxhttp://www.dentalcare.com/en-US/dental-education/continuing-education/ce462/ce462.aspx

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Approved PACE Program Provider

The Procter & Gamble Company is designated as an Approved PACE Program Provider

by the Academy of General Dentistry. The formal continuing education programs of this

program provider are accepted by AGD for Fellowship, Mastership, and Membership

Maintenance Credit. Approval does not imply acceptance by a state or provincial board

of dentistry or AGD endorsement. The current term of approval extends from 8/1/2013 to

7/31/2017. Provider ID# 211886

OverviewClinical errors occur as a consequence of improper patient preparation or management, technique and

exposure. Correct technique and proper patient management skills are essential to maximize the outcome

and the information obtained from digital radiographic images, while at the same time minimizing patient

radiation exposure. This course will provide an overview of digital imaging, a review of technique principles

and the identification and correction of common errors that occur in digital intraoral and panoramic imaging.

Learning ObjectivesUpon completion of this course, the dental professional should be able to:

• Describe the principle imaging concepts used in digital intraoral and panoramic imaging.

• Discuss the receptors used in digital radiography.

• Identify and correct common errors that occur in digital intraoral radiography.

• Identify and correct common errors that occur in digital panoramic radiography.

Course Contents• Glossary

• Introduction• Digital Intraoral Imaging Overview

Receptor Types

Advantages and Disadvantages• Review of the Basic Principles of Intraoral

Radiography Rules of Accurate Image Formation

Review of Techniques• Common Intraoral Errors

Technical Errors

Exposure Errors Miscellaneous Errors

• Digital Panoramic Imaging Basic Principles of Panoramic Imaging

Focal Trough Patient Preparation and Positioning

• Criteria for a Diagnostic Panoramic Image

• Common Panoramic Errors Alignment Errors

Imaging Errors

• Summary• Course Test Preview• References• About the Author

Glossaryabsorption - transfer of some or all of x-rayphoton energy to material or matter; dependent

on the energy of the x-ray beam and composition of

the absorber

analog data - analog data is characterized by a

continuous grayscale from black to white

analog to digital converter (ADC) - device thatconverts the analog output signal into numeric data

based on the binary number system of 0 and 1

area array - matrix or arrangement of pixels in

columns and rows used in intraoral direct digitalimaging

artifact - an object on a radiograph that is not part

of the actual image which may render the imagenon-diagnostic

attenuation - process in which an x-ray beam isreduced in intensity by passing through material. A

combination of absorption and scattering processes

results in a reduction of the beam intensity

binary number system - computer language inwhich two digits, 0 and 1, are used to represent

information

brightness - digital equivalent to density, or overalldegree of image darkening.

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cassette - a metal, plastic or cardboard light-tightcontainer that holds a plate receptor for extraoral

imaging

charge coupled device (CCD) - solid-state,silicon chip detector that converts light or x-rayphotons to an electrical charge or signal

collimation - device used to restrict the size and

shape of the x-ray beam

complimentary metal oxide sensor (CMOS) -solid-state detector similar to the CCD with built-in control functions, smaller pixel size and lower

power requirements

complimentary metal oxide sensor active pixelsensor (CMOS-APS) - CMOS detector with active

amplifying transistors integrated in each pixel todecrease noise and improve signal output

compression - computer methods used toreduce the image file size so it can be transmitted

faster and take up less storage space;compression schemes can be lossy or lossless

contrast - the difference in densities betweenvarious areas on a radiograph; high contrast

images have few shades of gray between blackand white while low contrast will demonstrate

more grays

density - overall degree of blackness or imagedarkening of an exposed film; comparable tobrightness in digital imaging

diagnostic - radiographic image that properly

records and adequately covers all structurespresent in a given anatomical area with optimal

density and contrast

digital image – a video image in pixel format

that can be stored in the computer memory forprocessing

digitization - conversion of an incoming analogsignal into a digital or numeric value for storageand processing

direct sensor - receives radiation directly like filmand deposits the energy in the electron wells or

picture elements

double exposure - a radiographic image that hassuperimposed images due to exposing a receptor

twice prior to scanning; this error is only possiblewith plate receptors

electron well - individual pixel into which x-ray orlight energy is deposited during x-ray exposure

elongation - image distortion in the vertical plane

that produces a long or stretched out version of therecorded structures rather than their true shape and

dimension; usually the apex is not visible

emulsion - plate receptors have a crystalline

halide emulsion of a europium-activated bariumfluorohalide that stores the latent image

exposure time - regulates the period of time over

which electrons are released from the cathode;altering the time setting influences the quantity of

x-rays and image density or darkness

focal spot - anode tungsten target where x-rays

are generated; focal spot size should be as small aspossible in the range of .5 to 1.5 mm; the size has

an influence on image quality in terms of sharpnessand geometric distortion

focal trough - area or zone of sharpness inpanoramic imaging where the jaws must be

positioned in order for the structures to be in focuson the resulting image

foreshortening - image distortion in the verticalplane that produces a short, stumpy version of the

recorded structures rather than the true shape anddimension of the structures

Frankfort plane - used to align the vertical plane of

the head in panoramic imaging; line or positioninglight that connects the tragus of the ear to theinfraorbital rim and is aligned parallel to the floor

ghost image - an artifact produced in panoramic

radiography by a remnant image from the opposite

side of the dental arches during exposure; someghost images are inherent in panoramic technologywhile others can be avoided through proper patientpreparation

gray level - measure of image brightness or

intensity in a range between black and white

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horizontal angulation - movement of the x-rayhead and PID in a horizontal plane; right to left, or

mesial to distal, which controls the ability to directthe x-rays through the proximal surfaces of the

teeth.

image enhancement - image processing

operations that are used to view details of theimage in different ways; sometimes referred to as

manipulation

image matrix - layout or grid of pixels in rowsand columns with each pixel corresponding to aspecific location and representing the brightness

or intensity in that location

indirect sensor - receptor receives x-rays uponexposure and stores the energy until released via

a laser scanning process

interproximal - the areas between teeth in thesame arch, mesial and distal; the x-ray beammust be directed through the proximal surfaces

in order to open teeth contacts and examine forcaries

kilovoltage (kVp) - regulates the high voltageelectrical circuit by adjusting the potential

difference between the electrodes; alteringthe kilovoltage setting influences the quality or

penetration of the x-rays and image contrast

latent image - the energy stored in a receptorthat represents the captured data prior toprocessing and viewing the visible image

linear array - solid-state detector that consists

of a few rows of pixels; used in direct digitalextraoral imaging

lossy - storage method in which some data islost but the compressed file is still capable of

producing a diagnostically acceptable image

lossless - storage method in which no

information is lost in the compression of a file

magnification - equal enlargement or distortionof the radiographic image; deviation from its

actual true overall size; magnification can beminimized by controlling receptor and source

distance factors

marginal - radiograph that may be adequate anddiagnostic only in par; it may be adequate when

combined with other views taken in survey thatdemonstrate the compromised area

midsaggital plane - vertical plane that divides thebody in half and is drawn at the midline; used in

panoramic imaging to center and position the headin the horizontal plane

milliamperage (mA) - regulates the low voltage

electrical supply by adjusting the number ofelectrons flowing in the electrical circuit; alteringthe milliamperage influences the quantity of x-rays

produced and image density or darkness

non-diagnostic - radiographic images inwhich any error in patient preparation, receptor

placement, angulation, exposure or processingprevents visualization of the required region of

interest; this type of radiographic image wouldrequire a retake

overexposure - a radiographic image that is toodark or high in density due to incorrect and/or

excessive exposure factor settings

photostimulable phosphor plate (PSP) - digital

receptor with a polyester base coated with acrystalline halide emulsion

photostimulation - emission of visible light after

excitation by a laser light beam

photomultiplier tube - electron tube that converts

visible light into an electrical signal

pixel - picture element; individual cell of the imagematrix in which the value of the cell determines

brightness

positioning indicating device (PID) - device

located at the end of the tubehead used to alignthe x-ray beam in the vertical and horizontal planes

and to center over the receptor; formerly known

as the x-ray cone radiolucent - dark or black areason the radiograph where x-rays penetrated thestructures and interacted with the receptor

radiopaque - light or white areas on theradiograph where x-rays were partially or

completely absorbed by the structures

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Random Access Memory (RAM) - temporarymemory of the computer in which programs and

information are stored

receptor - any device or medium that transformsx-ray energy into a latent image that can be madevisible by processing procedure

resolution - measures how well a radiographic

image reveals small objects that are closetogether; measured in line pairs per millimeter

sensor - a receptor device used in digitalradiography

shape distortion - deviation from the true

shape and size of an object related to unequalmagnification of different parts of the same object;

minimized by object receptor parallelism and rightangle entry of the x-ray beam

sharpness - ability of a radiograph to define anedge or display density boundaries

split beam radiography - use of a narrow vertical

slit x-ray source rotating at the same speed as theimage receptor but in opposite directions around astationary object; structures are depicted sharply

because they move past the slit at the same rateas the receptor

storage phosphor - another term or name for

photostimulable phosphor plate receptors

teleradiography - process of remote transmission

and viewing of digital images

tomography - technique that provides an imageof any selected plane through the body while the

images of the structures above and below thatplane are blurred out of focus

underexposure - a radiographic image that is toolight due to incorrect and/or insufficient exposure

settings

unsharpness - loss of image edge detail due toproduction of a fuzzy zone (penumbra) or falseshadow around the actual image; unsharpness

can be minimized by controlling receptor andsource distance factors

vertical plane - movement of the x-ray head andPID in a vertical plane (up and down); used to

control the length of recorded object(s)

XCP (eXtension Cone Paralleling) - a receptorholding device designed to maintain a parallelrelationship among the receptor, teeth and the PID

IntroductionDigital radiographic imaging in dentistry is nothingnew. This technology was first introduced in the

mid-1980s but has made significant entry into theprivate practice, military dental services and dentaleducational institutions in the last decade. As

with any new technology there is a learning curveand a transition time before it becomes widely

adopted, but it’s only a matter of time beforedigital imaging replaces traditional film. There

are many conveniences associated with digitalimaging that make it an attractive alternative to

film, but the basic mechanics and principles ofradiographic technique remain the same. Likefilm-based imaging, the clinician is responsible

for the majority of errors and retakes that occur indental imaging. Regardless of the receptor, a non-

diagnostic radiographic image does not providethe information necessary to render a diagnosisor to provide proper treatment and results in

increased radiation to the patient. Clinician errorsoccur as a consequence of improper patient

preparation or management, technique andexposure. Correct technique and proper patient

management skills are essential to maximizethe outcome and the information obtained fromdigital radiographic images, while at the same

time minimizing patient radiation exposure.This course will provide an overview of digital

imaging, a review of technique principles and theidentification and correction of common errors that

occur in digital intraoral and panoramic imaging.

Digital Intraoral Imaging OverviewPrior to the acquisition of intraoral digital images,the clinician must create or access the patient’s

record and create or select a template for the

intended survey. As in film-based radiography,digital imaging requires x-ray interaction witha receptor, latent image processer and imageviewer. The receptors (direct or indirect sensors)

used in digital imaging are faster, and moresensitive thus requiring less radiation than film.

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x-rays interact with the phosphor, a latentimage is formed and stored until the energy is

released during a laser scanning process. Thelaser beam releases the energy in the form of

light proportional to the energy absorbed bythe plate. The light is captured, intensified bythe photomultiplier tube and converted into an

electronic signal. The ADC digitizes the data anddisplays the image on the computer monitor. As

such, the scanning step delays image displayon the monitor slightly. Before the plates can be

reused, the remnant energy must be removedor erased by exposure to intense light. In someupdated or newer systems, erasure is completed

after scanning but before the plate exits thescanner. PSP receptors have a larger surface

area, are thin and wireless and can be used likefilm. The plates require careful infection control to

avoid cross-contamination and gentle handling toavoid plate scars and image artifacts.

Advantages and Disadvantages

• Less radiation exposure – The National Council

on Radiation Protection and Measurements(NCRP) assessed the technological

advancements and the ALARA concept in2003. When all NCRP recommnedations aremet (including film speed, total digital imaging,

rectangular collimation, selection criteria, etc.)the amount of radiation is significantly reduced.

The choice to use protective aprons on adultpatients is up to individual dental offices only

if every NCRP recommendation is employedor unless required by the state. Thyroidshielding with a protective thyroid shield or

collar is strongly recommended for children andpregnant women, as these patients may be

especially susceptible to radiation effects.• Time Savings - less time is spent away from

the patient during processing and mountingactivities which provides more time for patienteducation and treatment.

• Image display - images can be displayed forpatient viewing and enlarged for the purposes

of patient education and treatment plan

presentation.• Storage and transferability - radiographs are

stored as digital images in the computer; theycan be transferred during the referral process

to specialty dental practices and sent withHIPAA permission to insurance companies

for more efficient claims processing. Digital

The energy received by the receptor must beconverted to digital data before it becomes usable.

This process differs slightly depending on thetype of digital system and receptor that is used.

Essentially, the information is transformed intonumeric or digital data which translates ultimatelyinto 256 shades of gray (0 black to 255 white).

Receptor Types

Digital receptors come in two basic formats; rigidwired, or wireless, sensors or phosphor plates.

Rigid digital receptors are based on charge-coupled device (CCD) or complimentary metaloxide semiconductor (CMOS) technology and

are categorized as direct sensors. CCD, CMOSand CMOS-APS sensors are solid-state detectors

made of silicon arranged in an area array of x-ray,or light sensitive pixels or electron wells. When

x-rays strike the silicon, an electrical chargeis emitted and deposited in the electron wells.

The electrical charge is converted into a grayscale image via the analog-to-digital converter(ADC). Wired sensors communicate with the

computer via an electrical cable, while wirelesssensors powered by a battery communicate via

a radio signal. Direct sensors are available insizes comparable to 0, 1, and 2 film packetsbut are thicker and rigid in construction. Not all

manufacturers have multiple sizes. The activesurface area is smaller than film, so the amount of

coverage is somewhat reduced. Direct detectorscan be reused for each successive projection and

the acquired image can be viewed almost instantlyafter exposure. Rigid sensors require carefulinfection control and barrier coverage to avoid

cross-contamination.

Photostimulable phosphor plates (PSP), alsoknown as storage phosphor plates (SPP), are

another system for capturing intraoral digitalimages. PSP are categorized as indirect digitalsensors as they require a scanning process to

digitize the image. PSP are flexible, wirelessreceptors similar in size and thickness to film.

Phosphor plates are available in the same sizes

as intraoral film including 0, 1, 2, 3 and 4. Notall manufacturers produce plates in multiplesizes. An individual plate must be used foreach projection in a survey, just like film. The

phosphor plates consist of a plastic base coatedwith a crystalline halide emulsion of a europium-

activated barium fluorohalide compound. When

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critical importance. Plates must be inserted andsealed inside a barrier before placement in the

mouth. After the plates are exposed, the externalbarrier should be cleaned using disinfectant

hand soap, rinsed and dried. Following gloveremoval and hand washing, the plates can bedropped out of the barrier into the transfer carrier

with the exposure side down. Since there area number of plate systems on the market, it is

best practice to consult and follow the specificmanufacturer’s recommendations for platehandling and disinfection. The importance of

effective infection control was demonstrated inan investigation by Kalathingal and others. The

study found that that nearly 58% of the phosphorplates tested yielded bacterial colonies and

nearly 16% of those demonstrated hemolyticgrowth. The investigators recommended periodicethylene oxide gas sterilization of phosphor plates

with re-emphasis of proper handling for barrierplacement and removal.

Review of the Basic Principles ofIntraoral Radiography

Rules of Accurate Image Formation

In order to produce diagnostic intraoral images,the Rules of Accurate Image Formation must be

applied. The rules listed below include those that

can be controlled by the clinician.1. The x-ray source-to-object distance should be

as long as practical.2. The object-to-receptor distance should be as

short as possible.3. The receptor should be parallel to the long

axis of the tooth.

radiographic images can be incorporated intoa complete electronic patient record with less

likelihood of lost records or images.• Protection of the environment - advantages

with reduced waste production and disposalfrom film wrappings and processing chemicals.A complete electronic patient record helps to

reduce paper consumption and associatedcosts.

The disadvantages to digital imaging include the

initial cost of the system hardware, software, andadaptation or replacement of exisitng equipment.There is a learning curve for the dental

professional in using digital radiography system,getting used to the placement of the sensor and

software operation. Finally, to avoid any possiblelegal issues, the original image(s) should be saved

before performing enhancements or manipulationfor further diagnostic evaluation.

The primary disadvantages with direct digital

receptors are the rigidity and thickness of the

receptor and presence of the wire. The lack offlexibility and the attached wire may interfere

with optimal receptor placement and producediscomfort both of which may result in moreretakes. Infection control is another challenging

aspect of digital imaging because rigid digitalreceptors cannot be sterilized. However, they

can be disinfected with ADA or EPA approvedproducts and typical disinfection techniques.

The clinician must follow the manufacturer’sinstructions for proper preparation and coverageof the receptor, as well as barrier removal

techniques. Direct saliva contact with the receptorand electrical cable must be avoided to prevent

cross-contamination. Several investigations haveindicated that the barriers used on rigid digital

sensors can become torn during use, resulting incontamination of the sensor with bodily fluids. Toprotect rigid sensors more effectively, the Center

for Disease Control (CDC) recommends a doublebarrier approach with both an internal and external

barrier. (Figure 1)

Phosphor plate receptors are wireless andmore flexible than rigid receptors, producing lessdiscomfort for the patient. Disadvantages of

phosphor plate systems include plate artifacts,plate longevity, image resolution and the scanning

step. Effective infection control procedures are of

Figure 1. Rigid receptor should be covered withinternal and external barrier to protect the receptorfrom cross-contamination with oral fluids.

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placed into the mouth parallel to the crowns ofthe maxillary and mandibular posterior teeth. The

horizontal angulation directs the x-rays through thecontacts of the posterior teeth. The clinician may

find it helpful to place a fingertip in the contact pointto visualize the correct horizontal entry of the x-raybeam and avoid overlapping. In addition, most PID

collimators have lines on them that can be usedto sight the entry of the x-ray beam through the

contact points. Receptors may be positioned in thehorizontal or vertical dimension and may be taken

in both the posterior and anterior segments of thedentition.

The bisecting angle technique is considered tobe a secondary or alternative periapical imaging

technique. At times it may not be possible toachieve a parallel placement of the receptor

due to anatomical factors, patient discomfort orcooperation issues. This technique is accomplished

by placing the receptor as close to the tooth aspossible in an angular position. The central rayof the x-ray beam is directed perpendicular to an

imaginary line that divides or bisects the angleformed by the long axis of the tooth and the plane

of the receptor. When the x-ray beam is notdirected perpendicular to the bisecting plane, errorsin the vertical plane will occur.

Common Intraoral Errors

Technical ErrorsElongation is a form of shape distortion in whichthe projected image is longer than the actual

4. The x-ray beam should be directed at a rightangle to both the tooth and receptor.

When these rules are followed, the image quality

will be optimal but if violated, image qualitycan be compromised. A review of the basictechniques used in intraoral digital imaging

follows.

Review of Techniques

The paralleling technique is the preferred

method for periapical imaging because it mostclosely conforms to the Rules of AccurateImage Formation. The paralleling technique

is accomplished by placing the receptorparallel to the long axis of the tooth. Once

this parallel relationship has been established,the central ray of the x-ray beam is directed

perpendicular to both the tooth and receptor.Receptor instruments with x-ray beam guides

help standardize technique and avoid errors,particularly cone cuts. The paralleling technique,when performed correctly, is superior to the

bisecting angle technique.

The bitewing technique is a parallelingtechnique used to examine the crowns andinterproximal surfaces of the teeth. When taken

correctly, bitewings are particularly useful inthe detection of dental caries and evaluation

of alveolar bone levels. The receptor must be

Figure 2. In the paralleling technique, thereceptor is placed parallel to the long axis of thetooth and the central ray is directed at a rightangle to both.

Figure 3. In the bitewing technique, the x-raysare directed through the proximal contacts of theposterior teeth and at +5º to +10º vertical angle.

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paralleling technique, foreshortening occurs when

the PID is more vertical than the long axes ofthe teeth or when the receptor is placed angular

rather than parallel to the teeth. In bisectingangle, foreshortening occurs when the PID is

more vertical than the bisecting plane that dividesthe angle formed by the teeth and the receptor.Length accuracy is critical in many dental

procedures and a retake is often indicated whenforeshortening is present. In either instance,

foreshortening is corrected by decreasing the

vertical angulation.

Proximal overlapping is yet another form ofshape distortion that occurs in the horizontal

plane. It widens structures and superimposesproximal surfaces onto each other. To open the

interproximal contacts between adjacent teeth,

objects. This is caused by incorrect x-ray beamangulation in the vertical plane. If the PID is

under angulated or too shallow relative to thelong axis of the teeth, an elongated image will

be produced. With the paralleling technique,elongation occurs when the PID is less verticalthan the long axes of the teeth. In bisecting

angle, elongation occurs when the PID is lessvertical than the bisecting plane that divides

the angle formed by the teeth and the receptor.With rigid sensors, elongation can occur with

paralleling instruments if the biteblock does notposition the sensor parallel to the teeth andexternal ring beam guide. If adhesive type

disposable biteblocks are used, the receptor canpop off the biteblock, producing image elongation.

With plate receptors, curvature of the plateduring placement and exposure can produce an

elongated appearance as well. Length accuracyis critical in many dental procedures and a retakeis usually indicated when elongation is present.

In either instance, elongation is corrected byincreasing the vertical angulation.

Foreshortening is another form of shapedistortion in which the projected image is shorterthan the actual objects. This is caused byincorrect x-ray beam angulation in the vertical

plane. If the PID is over angulated or toosteep relative to the long axis of the teeth a

foreshortened image will be produced. With the

Figure 4. In the bisecting angle technique, thereceptor is placed angular to the teeth with thecentral ray directed at a right angle to bisectingplane.

Figure 6. Foreshortening is an error in verticalangulation that produces a shorter than the normalimage of the teeth and surrounding structures.

Figure 5. Elongation is an error in vertical angulationthat produces a longer than normal image of theteeth and surrounding structures.

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can use facial landmarks or use their fingers toextend the PID and check for proper coverage.

If the receptor is positioned incorrectly in thepatient’s mouth, the resulting image will not cover

the required structures. Receptor placement can result in several types of positioning errors,

including crowns or apices cut off or improperlocation. When crowns are cut off, the periapicalregions are adequately seen but details of the

tooth crowns are missing. The operator shouldplace the bite block of the instrument on the

incisal or occlusal surface with at least 1/8 inch of

the receptor beyond the incisal or occlusal aspectof the teeth. Crowns can be cut off due to over-angulation or image foreshortening in which thecrowns are projected off the receptor. In addition,

rigid receptors have a small periphery of deadspace which needs to be considered in receptor

placement. To avoid cutting the apices off, the

the horizontal angulation of the x-ray beamneeds to be parallel to the teeth and receptor.

This directs the x-rays through the contactpoints of the teeth and at a right angle to the

teeth and receptor. If the overlaps are larger inthe posterior half of the image, the horizontalangulation was angulated too much from the

mesial toward the distal. The reverse is true foran image in which the overlaps are larger in the

anterior half of the image. Important informationabout interproximal caries and alveolar bonelevels can be obscured when contacts are

overlapped and a retake is often indicated whenoverlapping is present. This error is corrected

by directing the x-ray beam through the proximalcontacts with the open end of the PID parallel to

the buccal surfaces of the teeth.

If the PID is not centered over the receptor, the

x-ray beam will not uniformly expose it and theportion outside of the PID will be cut (missing).

The unexposed area will be completely whiteand follow a curved border if the collimator was

round and linear if rectangular. (Figures 8a and8b) Cone cuts occur frequently with tab bitewingtechniques when the clinician fails to align the

central ray to the center of the receptor. Theclinician tends to lose sight of the tab when

the patient’s mouth closes. Images with cone

cuts should be repeated if the information is notviewable on any other projection. Typically, thereis sufficient anatomic repetition in a full mouthsurvey such that one cone cut does not usually

require a retake. When taking bitewings, theclinician should ask the patient to smile in order to

view the bite tab to aid alignment. The clinician

Figure 7. Overlapping is an error in horizontalangulation that widens structures and superimposesproximal surfaces onto each other.

Figure 8a. Cone cuts are the result of impropercentering of the x-ray beam over the receptor. Awhite zone is produced in the region of the receptorwhere no x-rays were received. In this instance, arectangular cone cut occured.

Figure 8b. Round cone cut.

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Exposure Errors

Most dental x-ray machines compatible

with digital intraoral radiography have fixedkilovoltage and milliamperage controls, leaving

exposure time as the only adjustable variable.The time must be set for each periapical andbitewing to accommodate the different thickness

in structure from one location to the next andto maintain even image density throughout

the survey. Some manufacturers provide twokilovoltage settings, 60 kVp or 70 kVp, which

allows the clinician to adjust contrast or thedifferences in darkness. Exposure time is themost common variable. It allows the clinician

to change or adjust density or overall darknesson a radiographic image, but does not affect

contrast. Digital systems with automaticexposure correction minimize exposure

variations that result in overly light or darkimages.

An underexposed image will be light or low indensity and have less detail than a correctly

exposed radiographic image. Underexposureoccurs when the operator selects mA, kVp or

exposure time too low or when the patient’soverall size and structural thickness are notconsidered. An underexposed image cannot be

effectively improved by enhancement becauseall of the x-rays did not reach the receptor

to form the image. As a result, a retake willbe necessary to achieve a diagnostic level

of density and contrast. It is the clinician’sresponsibility to accurately evaluate patient sizeand select proper exposure factor settings for

each area to produce an optimal image andavoid retakes.

An overexposed radiographic image will be too

dark or high in density and difficult to discerndetail because the structures are “burned out.”Overexposure occurs when the operator selects

mA, kVp or exposure time that are too high orwhen the patient’s overall size and structural

thickness are not considered. An overexposed

image can be effectively improved by subtractingdensity from each pixel, except when thereceptors are oversaturated by extremelyhigh levels of radiation. It is the clinician’s

responsibility to accurately evaluate patientsize and select proper exposure factor settings

clinician must place the instrument bite block incontact with the teeth being imaged. (Figure 9a)The patient must be instructed to bite with

enough pressure to hold the biteblock in place.If the patient finds the biteblock and the receptor

uncomfortable, the clinician must either repositionthe receptor more lingual to the structures or use

a tissue cushion to reduce discomfort. At thesame time, the clinician must maintain the correctplacement to cover the desired structures. The

clinician must remember that each periapicaland bitewing in a survey has a particular location

with specific teeth and area requirements. In

complete or full mouth surveys, all apices, crownsand interproximal surfaces should be displayedwhen the composite views are assembledtogether. Close attention to placement and

location details are necessary to produce acomprehensive, diagnostic survey. (Figure 9b)

Figure 9a. A variety of placement errors can occurin intraoral imaging. In this instance, the apices werecut off.

Figure 9b. The molar periapical was placed too farforward and cut off the distal apex of the secondmolar.

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As a result, no x-rays were able to penetrate thestructures and produce an image on the receptor.

Backwards placement causes a blank or white

image as the result of exposing the wrong sideof the digital receptor. X-ray interaction with theexposure side is necessary for image production.

For plate receptors, the emulsion side must bedirected toward the source of radiation and for

rigid digital receptors the plain non-wired or non-battery side of the receptor must be directed

toward the x-ray source. (Figures 10a and 10b)

Miscellaneous ErrorsMotion unsharpness can occur if the patient,tube head or receptor moves during the exposure

producing a blurred image. Motion unsharpnessis most typically caused by patient movement.

The patient must understand and be able to holdcompletely still until the exposure is complete.

These images should be retaken unless thepatient is not able to cooperate or unless thetubehead is unstable and needs to be serviced.

Creasing, crimping or bending of plate receptors

prior to exposure and scanning will producepermanent scars on the plate and artifacts on

for each area to produce an optimal image andreduce unnecessary patient exposure.

Double exposures occur when the same plate

receptor is used twice during the survey. Thiscan occur if the clinician confuses an exposedplate with an unexposed plate and places it back

into the patient’s mouth. The scanned image willdemonstrate a dark image with superimposed

structures and an unexposed plate with no image.Retakes are almost always necessary because

of the structural superimpositions and overly darkimage. This error can be avoided if the clinician isorganized and keeps exposed plates separated

from unexposed plates. In addition, platereceptors must be erased with white light before

re-use to avoid a remnant image left on the plate.Double exposures cannot be produced with rigid

digital receptors.

Non-exposure is when a blank or white imageis produced as a result of not exposing thedigital receptor or failure to align the PID over

the receptor. Some direct digital systems have afixed time interval during which the receptor must

be exposed. Failure to execute the exposure in atimely manner may also produce a non-exposure.

Figure 10a. The exposure side of thereceptor must be directed toward the x-raysource to record a digital image. Rigidreceptor: exposure side on top; non-exposureside on bottom.

Figure 10b. Plate receptor: exposure side ontop; non-exposure side on bottom.

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degree to which an oral prosthesis interferes withdiagnostic quality depends on its type, location,

composition and how much it attenuates the x-raybeam. An intraoral prosthesis with a metallic

baseplate will completely obscure structuresof interest and render the image useless. Aprosthesis that covers the area of interest should

be removed, but it can be used in oppositionwhen taking images of the opposing arch. This

facilitates proper biting and receptor stabilization.In addition, eyeglasses, large earrings and

some facial piercings can produce foreign objectartifacts if they are between the x-ray source andimage receptor. These should be removed prior

to receptor exposure.

the resultant image. These scars appear as whitelines or scratches across the image. In addition,

plate scratches can occur from rough or improperplate handling or scanning techniques. Plate

bends or scratches produce permanent artifactsand require plate replacement. Therefore, donot bend the corners of the plate and handle the

plate surface carefully. There are commercialproducts available to cover or cushion the corners

of the receptor to soften the edges and to avoidbending.

If the patient has oral prostheses or other typesof foreign objects, they should be removed

prior to taking any radiographic images. The

Table 1. Summary of Intraoral Image Errors.

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beam is penetrating through both sides to imageone. The clinician must consider the overall

patient size and the head in particular. When thesettings are off significantly in either direction, the

result will be substandard and a retake is likely.Some systems have automated exposure controlsthat modulate exposure via radiation sampling

or head measuring techniques to help avoidexposure errors.

Focal Trough

The focal trough, or image layer, is locatedbetween the x-ray source and the receptor. It hasa horseshoe-shaped configuration theoretically

designed to conform to the “average jaw”size. Accurate patient positioning is critical to

obtaining an optimal result. Occasionally, thereis a mismatch between a patient’s jaw and the

predetermined form of the image layer. Imagedistortion occurs when structures are positioned

anterior or labial (narrows and blurs), posterior orlingual (widens and blurs) or a combination of thetwo relative to the focal trough. (Figure 11a) If

structures are positioned anterior or labial to thefocal trough, they will be closer to the receptor

while structures posterior or lingual to the focaltrough will be closer to the x-ray source. Thesemisalignments produce characteristic image

distortion patterns that, once recognized, assistthe clinician in the identification and correction of

errors. (Figure 11b)

Patient Preparation and Positioning

The first step in patient preparation is to explainthe procedure and elicit patient cooperation. The

clinician must direct the patient to remove oralprostheses, earrings, hearing aids, eyewear,

facial and oral piercing jewelry, napkin chains andnecklaces before making a panoramic exposure.

The clinician should follow the established safetyprotocols of the dental office which may includethe placement of a panoramic protective apron

(without a thyroid collar). The apron must fullyclear the back of the neck region; be high in

front, low in back. Placement of the protective

apron too high on the back of the patient’s neckor bunching it at the shoulders will produce aprotective apron artifact on the image. Whenpositioning patients for panoramic imaging,

manufacturer’s directions should be followedclosely, as each panoramic machine is slightly

different. In general, patients should be seated or

Digital Panoramic ImagingAs with digital intraoral radiography, panoramic

images can be acquired using direct or indirectdigital imaging systems. Digital panoramic

imaging utilizes either linear array CCD or CMOSdetectors or PSP receptors. With CCD or CMOSextraoral imaging, conventional film is replaced

by a long, vertical, rigid digital receptor a fewpixels wide. With PSP receptors, the plate is

configured in the same dimensions as panoramicfilm and can be placed directly into the cassette

without the intensifying screens. As with intraoraldigital imaging, a patient file must be created,the appropriate template or projection selected,

patient positioned, exposure made and imageviewed on the monitor. With PSP receptors, the

plate needs to be scanned before the image canbe viewed. The technique for preparing and

positioning the patient is the same as film-basedpanoramic radiography. Errors can be produced

when the patient is improperly prepared, the headalignment is incorrect and the exposure factorsare not properly selected. The quality of the

resulting image is ultimately the responsibility ofthe clinician and effective application of panoramic

imaging techniques. In panoramic imaging, the filesize is considerably larger than intraoral imagingand must be reduced by compression techniques

that facilitate storage without compromising thediagnostic quality of the image.

Basic Principles of Panoramic Imaging

Panoramic imaging is based on a combination oftomography and slit beam radiography which blursout some structures so others can be recorded.

This involves simultaneous rotation of a slit beamx-ray source and the image receptor in opposite

directions. The side closest to the receptor isrecorded while structures on the opposite side are

blurred out of focus. The x-ray source is fixed ata -10º angle and has a vertical slit aperture thatrotates behind the patient’s head in a lingual to

labial direction. The same exposure factors areused as in intraoral radiography, but in panoramic

imaging the time is fixed and the kVp and mA are

variable. Each manufacturer provides guidelinesfor patient exposure parameters. Generally, thelarger the individual is, the higher the kVp andmA settings and vice versa. Kilovoltage controls

the penetrating power of the x-ray beam and themilliamperage controls the number of x-rays that

are generated. One must remember that the x-ray

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with the nasolabial fold for edentulous patients.

(Figure 12c)

Criteria for a Diagnostic PanoramicImageHow do you know when you have a quality

image? You can compare your result with thefollowing criteria. A diagnostic panoramic image

should display the following features:

stand erect with the cervical spine as straight andas centered as possible. The patient’s midsagittal

plane should be aligned perpendicular to the

floor and the Frankfort plane aligned parallel tothe floor. (Figures 12a and 12b) The patient’steeth should be biting end-to-end in the biteblockgroove with the anteroposterior (AP) light aligned

with a specific anatomic landmark. Typically, theAP landmark is in the canine tooth or contact

on either the maxilla or mandible, or aligned

Figure 11a. In panoramic imaging, improperpatient alignment produces characteristicimage distortion patterns. Misalignment inthe AP plane either narrows or widens thestructures when positioned outside the focaltrough.

Figure 11b. Misalignment in the midsagittalplane produces narrow structures on one sideand wide structures on the other.

Figure 12a. Proper head alignment.Midsagittal plane is centered and alignedperpendicular to the floor.

Figure 12b. Frankfort plane is alignedparallel to the floor.

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• The image is free of technical, patientpreparation and exposure errors. (Figure 13)

Common Panoramic Errors

Alignment ErrorsThe diagnostic quality of a panoramic image

is largely determined by the same geometricconsiderations that apply to intraoral radiographic

images: the relative position of the patient’s jaws, teeth, x-ray beam and receptor. The

consequences of malpositioning andmisalignment are as equally problematic withpanoramic images as they are with intraoral

images.

Midsagittal Plane Errors – If the patient’s headis tilted, the image will appear crooked or skewed

diagonally across the image. One condyle willbe higher than the other, the occlusal plane will

appear crooked and distortion of teeth will beobserved right to left. (Figure 14) If the headis rotated or turned to one side, the result will

be under magnification of the side toward thereceptor and over magnification of the side

toward the x-ray source. One side appearsnarrowed and the other side appears widened.These errors present unequal right to left

distortion. None of the recorded structures arethe correct dimension particularly in the horizontal

plane. (Figure 15)

Vertical Head Errors – If the patient’s head istilted too far downward, not aligning the Frankfortplane, the arches will appear constricted. The

condyles will appear closer together and maybe cut off the top of the image. The overall

appearance will be that of a “Jack-O-Lantern

• The entire maxilla and mandible are recorded,

including the temporomandibular joints.• As patient anatomy allows, structures are

displaced symmetrically on both the right and

the left sides of the image.• A slight smile or downward curve of the

occlusal plane is evident.• The image demonstrates good representations

of the teeth with minimal under or over

magnification.• The patient’s tongue was in place against the

hard palate during exposure, eliminating thepalatoglossal airspace.

• The patient’s lips were closed during exposureavoiding burn-out of the anterior teeth crowns.

• Minimal or no cervical spine shadow is visible

and the anterior teeth are clearly seen.• The image displays acceptable levels of

contrast and density.

Figure 12c. AP plane is aligned with specificanatomic landmark.

Figure 13. This is an example of a radiographic image that meets the criteria fora diagnostic panoramic.

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trough. The image of the arches will be one ofoverall occlusal flattening and elongation of the

maxillary teeth. The general appearance is thatof a frown configuration of the Curve of Spee.

The condyles will be farther apart and may becut off the sides of the image. The orbital and

grin” due to the accentuated Curve of Spee. Inaddition, the lower anterior teeth are positioned

lingual to the focal trough and appear blurred,widened and foreshortened. (Figure 16) If the

patient’s head is tilted too far upward, superiorstructures will be placed lingual to the focal

Figure 14. Panoramic image demonstrating a midsagittal head tilt. Note thecrooked display of the occlusal plane and widened structures on one side andnarrow structures on the other.

Figure 15. Panoramic image with a midsagittal head turn or rotation. Note thestructures are distorted right to left with one side narrowed and the other sidewidened.

Figure 16. The head is tilted downward on this panoramic image which

demonstrates an exaggerated grin with blurred, foreshortened lower anterior teeth.

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Cervical Spine Slump – When the patient’scervical spine is slumped forward, instead ofremaining perpendicular to the floor, it is then

positioned too far anteriorly. The vertebrae areprojected more visibly on the lateral borders of

the image and obscure the anatomic structuresof the ramus. The cervical vertebrae become

compressed, block passage of the x-ray beamand produce a column or triangular-shapedmidline radiopacity that obscures the anterior

teeth and adjacent structures. (Figure 20)

Motion Unsharpness – Vertical, horizontal or

compound patient movements can produceartifacts on panoramic images. With intraoralprojections, motion produces generalizedunsharpness; with panoramic projections, motion

unsharpness only affects the portion of theimage being exposed at the time the movement

occurred. Therefore, depending on the extentand duration of movement, only a portion of

nasal structures will be out of focus and the hardpalate superimposed over the maxillary teeth.(Figure 17) These errors present alterations

particularly in the configuration of the occlusalplane and involve one arch or the other.

Anteroposterior Errors – If the patient’s head

is positioned too far forward, the anterior teethwill be labial to the focal trough and will appearblurred and narrower than the actual objects.

Overlapping of the contacts will be evident andoften superimposition of the spine onto the rami.

(Figure 18) Conversely, if the patient’s head is

too far back, the anterior teeth will be lingual tothe focal trough and appear blurred and widerthan the actual objects. Excessive ghostingof the opposite mandible and condyles cut off

the sides accompany distortion of the teeth.(Figures 19a and 19b) These errors present

width alteration involving both the maxillary andmandibular anterior teeth.

Figure 17. The head is tilted upward on this panoramic image which displaysfrown configuration with blurred, elongated upper anterior teeth. Note hard palatesuperimposition over maxillary teeth apices and distorted nasal cavity structures.

Figure 18. On this panoramic image, the head was positioned too far forwardwhich most noticeably narrows both the maxillary and mandibular anterior teeth.Also note evidence of a slight head tilt.

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Figure 19a. On these panoramic images, the head was positioned too far back orlingual to the focal trough. This image demonstrates some anterior widening andghosting of the opposite mandible.

Figure 19b. Extreme example of AP malpositioning with excessive ghosting of theopposite ramus and spine and cut-off condyles. Note head is tilted upward as well.

Figure 20. When the cervical spine is slumped, a triangular radiopacity is createdin the midline which can obscure the anterior structures. Also, note a midsagittalpositioning error as well.

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clinician should plan ahead and have strategiesfor handling these problems. If the patient is

able, instructing them to lower their right shoulderdown during machine rotation may solve the

problem. Other strategies include having thepatient bend the right knee to lower the entire

right side, instructing the patient to hold thehandlebars underhanded or cross-handed ratherthan over-handed or seat the patient so their

hands and arms can hang down on the sideto bring their shoulders down. Sometimes a

combination of these strategies is effective as

well. Other obstacles may include fixed, slumpedspines and Dowager’s hump anatomy. If thesource and receptor fail to rotate, only a portionof the jaw will be imaged instead of the entire jaw.

Occasionally, motion unsharpness occurs in thehorizontal plane if the shoulder is bumped without

prior warning. Unfortunately, some patients

the exposure may be blurred while the restof the image is within acceptable limits. Very

short-duration movement may be difficult todetect because the resulting artifact can look

suspiciously like a pathological condition suchas a healed fracture. Generally speaking, the

artifact reflects the plane in which the movementoccurred.)

Shoulder Interference – Panoramic imaginginvolves a complex series of coordinated,

simultaneous movements. Because of this,

mechanical errors can affect the acquisition andquality of the image. One of the most commonobstacles to smooth rotation is contact with thepatient’s shoulders. The clinician must take into

consideration the neck and shoulder anatomyof the patient. If the patient’s neck is short and

thick with heavy shoulders, contact is likely. The

Figure 21a. Movement produces motion unsharpness in the plane of the headmovement. Vertical head movement up and down produces spikes and blurredstructures in the areas of movement.

Figure 21b. Horizontal movement of the head to one side blurs the structures inthe area of movement. This may occur concomitantly with shoulder contact.

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1. They are projected onto the side opposite tothe original object.

2. The image is reversed compared to the

original object.3. The ghost appears higher in position than the

original object.4. The ghost image appears magnified and

unsharp in the horizontal plane.

Other avoidable artifacts include the palatoglossal

airspace and open lips, both of which produceradiolucent areas that interfere with interpretation.

To avoid the palatoglossal airspace artifact, the

patient’s tongue must be held against the palateduring exposure. If the clinician fails to give thisinstruction, the air space between the tongue andthe hard palate will produce a radiolucency above

the apices of the maxillary teeth. (Figure 23)Similarly, the patient’s lips should remain closed

to avoid burnout of the anterior teeth crowns.

just don’t fit into the machine properly so analternative imaging technique such as the lateral

jaw technique may be employed to accommodate

those patients.

Imaging Errors

The degree to which a panoramic image blurs

out objects outside the focal trough is dependenton how dense those objects are. Ghost imagesare remnant images from the opposite side of

structures or objects that cannot be completelyblurred out of focus. Some ghost images are

inherent in panoramic imaging, but others can

be completely avoided. Although a number ofobjects can produce ghost images, the mostcommon ghost images are the angle and ramusof the mandible and earrings, or the like, not

removed prior to exposure. (Figures 22a and 22b)Ghost images have particular characteristics and

can be recognized by the following features.

Figure 22a. Ghost images of the opposite ramus appear bilaterally on thisedentulous panoramic image. Note evidence of a slumped cervical spine in themidline.

Figure 22b. Ghost images of hoop earrings are displayed on this panoramicimage. Note presence of head tilt and head up alignment errors.

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increase radiation exposure to the patient. Withproper patient preparation, optimal techniques

and attention to detail, the clinician can providethe dental team with diagnostic intraoral and

panoramic images that permit proper diagnosisand treatment of patients.

SummaryThe goal of the clinician should be to produce

a quality radiographic image the first time. Asubstandard radiographic image is worse than

no image at all because it does not provide thenecessary diagnostic information and retakes

Figure 23. The “bat-shaped” radiolucency above the maxillary teeth crowns isthe palatoglossal airspace. To avoid this artifact, direct the patient to press thetongue against the roof of the mouth during exposure. Note error in forward APalignment as well.

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Table 2. Summary of Panoramic Image Errors.

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Course Test PreviewTo receive Continuing Education credit for this course, you must complete the online test. Please go to:

www.dentalcare.com/en-US/dental-education/continuing-education/ce462/ce462-test.aspx

1. When retaking this bitewing, the clinician would to correct the error

displayed on this image.

a. center x-ray beam over the receptor

b. change the horizontal angulation

c. place the receptor more apically

d. increase the vertical angulation

2. The clinician failed to and that resulted in this periapical image error.

a. ask the patient to remove the maxillary partial denture

b. direct the horizontal angle through the teeth contact points

c. selected an exposure time setting too low for posterior teeth

d. use the correct vertical angulation to control shape distortion

3. is most likely eliminated by use of a receptor instrument with an x-raybeam guide ring.

a. Cone cutting

b. Overexposure

c. Proximal overlap

d. Placement error

http://www.dentalcare.com/en-US/dental-education/continuing-education/ce462/ce462-test.aspxhttp://www.dentalcare.com/en-US/dental-education/continuing-education/ce462/ce462-test.aspx

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4. When retaking this periapical radiograph, the clinician would have to

to avoid the same mistake.

a. center the x-ray beam over the receptor

b. placement the receptor in the correct location

c. instruct the patient to hold still during exposure

d. increase the exposure time setting on the machine

5. best describes the image error recorded on this periapical view.

a. Image foreshortening

b. Horizontal overlapping

c. Underexposure to x-rays

d. X-ray beam not centered

6. The vertical angulation controls the .

a. length of the structures

b. centering the x-ray beam

c. placement of the receptor

d. proximal entry of the x-rays

7. most effectively controls shape distortion.a. Size of the focal spot

b. Source to object distance

c. Object to receptor distance

d. Object-receptor parallelism

8. When the clinician is using the bisecting angle technique, the central ray is directed at a rightangle to the .a. long axis plane

b. image receptorc. dividing plane

d. teeth crowns

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9. Each of the following items would produce image elongation except

a. under angulation in the vertical plane

b. curvature of a phosphor plate receptor

c. diagonal alignment in the horizontal plane

d. alignment with the tooth in bisecting technique

10. When determining the exposure time for intraoral imaging, the clinician should take into

consideration whether it is .a. posterior or anterior area

b. dentate or edentulous

c. child or adult patient

d. all the above

11. would correct the image error recorded on this dental image.

a. Decrease the positive vertical angle of the PID

b. Direct the central ray toward the middle of the receptor

c. Position the receptor in the mouth to cover the required teeth

d. Direct the horizontal angulation through the contacts of the teeth

12. If the apices are cut off on a periapical image, was the most likely cause.a. foreshortening

b. receptor placement

c. horizontal overlapping

d. improper beam centering

13. If the patient’s head was aligned as shown in this picture, would be

evident on the resultant panoramic image.

a. frown appearance of the occlusal plane

b. one side wider, the other side narrowed

c. anterior teeth appear blurred and widened

d. condyles would be cut off the top of the image

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20. Each of following is a criterion for a diagnostic panoramic image except .

a. a slight smile or downward curve of the occlusal plane

b. the maxilla, mandible, temporomandibular joints recorded

c. a clear view of the interproximal surfaces of all of the teeth

d. a symmetrical display of the anatomic structures right to left

21. Each of the following errors is present on this panoramic image except a .

a. protective apron too high on neck

b. slumped cervical spine

c. head is tilted upward

d. midline is off-center

22. When the patient’s head is positioned too far backward in panoramic imaging, the clinicianmay observe all of the following manifestations except .

a. excessive ghosting of the spine and mandible occurs

b. the image is enlarged and the condyles are not recorded

c. the occlusal plane has a diagonal or crooked appearance

d. the structures appear wide and blurred compared to normal

23. The was improperly aligned such that it caused the problem evident on

this panoramic image.

a. Frankfort plane

b. midsagittal plane

c. anteroposterior plane

d.cervical spinal column

24. causes superimposition of the hard palate over the apices of the maxillaryteeth on a panoramic image.a. Patient’s head forward

b. Cassette placed too lowc. Patient’s head is too high

d. Head rotated to one side

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25. caused the distortion apparent on this panoramic image.

a. Patient’s head tilted too high up

b. Patient’s head tilted too far down

c. Patient’s head is positioned too far back

d. Patient’s head is turned toward one side

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References1. American Dental Association Council on Scientific Affairs. The use of dental radiographs: update

and recommendations. J Am Dent Assoc. 2006 Sep;137(9):1304-12.2. Bedard A, Davis TD, Angelopoulos C. Storage phosphor plates: How durable are they as a digital

dental radiographic system? J Contemp Dent Pract. 2004 May 15;5(2):57-69.3. Kohn WG1, Collins AS, Cleveland JL, et al. Guidelines for infection control in dental health-care

settings--2003. MMWR Recomm Rep. 2003 Dec 19;52(RR-17):1-61.

4. Danforth R (Ed). Successful panoramic radiography. Academy of Dental Therapeutics andStomatology. PennWell Corporation, Tulsa, 2008.

5. Ergün S, Güneri P, Ilgüy D, et al. How many times can we use a phosphor plate? A preliminarystudy. Dentomaxillofac Radiol. 2009 Jan;38(1):42-7.

6. Hildebolt CF, Couture RA, Whiting BR. Dental photostimulable phosphor radiography. Dent ClinNorth Am. 2000 Apr;44(2):273-97, vi.

7. Hocket SD, Honey JR, Ruiz F, et al. Assessing the effectiveness of direct digital radiography

barrier sheaths and finger cots. J Am Dent Assoc. 2000 Apr;131(4):463-7.8. Hubars JS, Gardiner DM. Infection control procedures used in conjunction with computed dental

radiography. Int J Comput Dent. 2000 Oct;3(4):259-67.9. Iannucci JM, Jansen-Howerton L. Dental radiography: Principles and techniques. 4e. St. Louis,

Mo. Elsevier, Saunders. 2012.10. Kalathingal SM, Moore S, Kwon S, et al. An evaluation of microbiologic contamination on

phosphor plates in a dental school. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009Feb;107(2):279-82.

11. Matzen LH, Christensen J, Wenzel A. Patient discomfort and retakes in periapical examination of

mandibular third molars using digital receptors. Oral Surg Oral Med Oral Pathol Oral Radiol Endod.2009 Apr;107(4):566-72.

12. Miles DA, Langlais RP. NCRP report no. 145; New dental x-ray guidelines: Their potential impacton your dental practice. Dentistry Today. September 2004. Accessed April 10, 2013.

13. Parks ET, Williamson GF. Digital radiography: An overview. J Contemp Dent Pract. 2002 Nov

15;3(4):23-39.14. ScanX® Digital imaging system in-line erase. Instruction manual. Air Techniques, Inc. Melville, NY,

2012. Accessed March 18, 2013.15. Scarfe WC, Williamson GF. Practical panoramic radiography. Online Continuing Education Course.

Dental ResourceNet. Procter & Gamble Company, Cincinnati, Revised, 2011.16. Versteeg CH, Sanderick GC, van Ginkel FC, van der Stelt PF. An evaluation of periapical

radiography with a charge-coupled device. Dentomaxillofac Radiol. 1998 Mar;27(2):97-101.

17. Williamson GF, Parks ET. Digital radiography: A new technology for dental imaging. Access2006;20:15-19.

18. Williamson GF. Better techniques, better radiographs. J Prac Hyg 2003;12:10-15.19. Williamson GF. Digital radiography in dentistry: Moving from film-based to digital imaging.

American Dental Assistants Association, Chicago, 2004.20. Yoshiura K, Nakayama F, Chikui T, et al. Effects of the automatic exposure compensation on the

proximal caries diagnosis. Dentomaxillofac Radiol. 2005 May;34(3):140-4.

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About the Author

Gail F. Williamson, RDH, MS

ProfessorDepartment of Oral Pathology, Medicine & Radiology

Indiana University School of Dentistry

Gail Williamson received an AS in Dental Hygiene, a BS in Allied Health and aMS in Education from Indiana University. A veteran teacher, Prof. Williamson has

received numerous awards for teaching excellence during her academic career. Sheis a published author and presents continuing education courses on topics in Oral and Maxillofacial

Radiology nationally.

Email: [email protected]

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