New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Dental Radiography

by: Courtney Johnston

Dental Radiography DEA 125

Courtney Johnston

GPA 3.98


Almost Ready


These notes were just uploaded, and will be ready to view shortly.

Purchase these notes here, or revisit this page.

Either way, we'll remind you when they're ready :)

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

Class Notes
25 ?




Popular in Course

Popular in Dentistry

This 11 page Class Notes was uploaded by Courtney Johnston on Monday October 12, 2015. The Class Notes belongs to DEA 125 at Front Range Community College taught by Staff in Fall. Since its upload, it has received 45 views. For similar materials see /class/221859/dea-125-front-range-community-college in Dentistry at Front Range Community College.

Similar to DEA 125 at

Popular in Dentistry


Reviews for Dental Radiography


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 10/12/15
DEA 125 Radiology I Producing Quality Radiographs At the completion of this lesson the student will with at least 70 accuracy on a written andor oral exam Ni 9939er waopog II 139 39 Identify the basic 1 39 of an radiograph Differentiate between radiolucent and radiopaque areas on a dental radiograph and give an example of each Describe radiographic density and contrast Summarize the factors affecting the radiographic image Differentiate between subject contrast and film contrast List the geometric factors that affect image sharpness List the rules for casting a shadow image List the factors that in uence magnification and distortion Describe how mA kVp and exposure time affect film density Discuss how kVp affects contrast Differentiate between shortscale contrast and longscale contrast Explain targetsurface objectfilm and targetfilm distances Explain the Inverse Square Law and give two examples Basic Requirements All parts of the structures must be shown on the film as close to their natural shapes and sizes at the patient s oral anatomy The area examined must be shown completely with enough surrounding tissue to distinguish between the structures shown The film must be high in quality with proper density contrast and definition A diagnostic radiograph depends on these 3 factors AND the opinion of the dentist Terminology Radiolucent l The portion of the radiograph that is dark or black 2 Structures permit the passage of xrays with little or no resistance 3 Examples soft tissues and air space Radiopaque l Refers to that portion of a radiograph that appears light or white 2 Structures are dense and absorb or resist the passage of xrays 3 Examples enamel dentin and bone Radiopaque and radiolucent are relative terms Density 1 Also known as film blackening 2 The amount of light transmitted through the film 3 If a lot of light is transmitted through the film the radiograph is said to have little density 11gt U0 III m 11gt 031 C 4 The amount of density required on a radiograph is operator preference Contrast 1 How sharply dark and light areas are differentiated 2 A good lm will have black white and areas of gray on the lm a Shortscale contrastidescribes a radiograph in which the density differences between adjacent areas are large b Longscale contrastidescribes a radiograph in which the density differences between adjacent areas are small The contrast is small and gradual Sharpness l A geometric factor that refers to the detail and clarity of the outline of the structures shown on the radiograph 2 Movement of the patient film or the tube head generally causes unsharpness Factors Affecting the Image Detail and visibility of a radiograph depends on 2 independent factors radiographic contrast and sharpness Radiographic Contrast l The visible difference between densities on a radiograph 2 Depends on 2 separate factors a Subject contrastithe differences in absorption of radiation by the tissues 9 3 factors affect The patient gt KVp I Inverse relationship between kVp and contrast I Higher kVp produces lower subject contrast I Helps to create more of a longscale contrast I Lower kVp produces higher subject contrast I Helps to create more of a shortscale contrast gt Scatter radiation b Film contrastia characteristic of the film and processing 9 Inherent contrast built into the film by the manufacturer gt 3 factors affect I Film typeidetermined by the manufacture I Exposure 0 UndereXposed or overexposed film will result in poor contrast and reduced quality of the radiograph I Processing I Extremely important I Film processing is under the control of the operator I Improper time and temperature the film will not have the contrast built into it Sharpness l Refers to the clarity of the outline of the structures on an image of a radiograph 2 2 factors affect sharpness a Geometric Factors O 6 factors contribute to the radiographic image Focal spot size I The smaller the focal spot size the sharper the image I The larger the focal spot the more opportunity to have penumbra or a partial shadow gt Target film distance I The distance between the source of xray production and the film I PID establishes the target film distance I The longer the target film distance the less divergent the xray beam I A long target film distance had the xrays in the center of the beam and they are nearly parallel I A longer target film distance will have less image magnification gt Objectfilm distance I The distance between the object being radiographed and the film I Ideally the film is placed as close to the object as possible I The closer the film is to the object the sharper the image and less magnification I The farther away the film the image will become fuzzy an increase in penumbra gt Movement I May involve the patient the film or the tube head I Any of these things will cause a loss of sharpness gt Screen thickness I Intensity screens used with extraoral radiographs are made of crystals that emit light when struck by xrays I Intensifying screens require less radiation to expose a film therefore exposing a pt to less radiation I The thicker the screen the less radiation needed to expose the film but the image is less sharp gt Screenfilm contrast I The film should be in close physical contact with the intensifying screen I Poor screenfilm contact results in wide spread of light and penumbra b Crystal Size 9 In uenced by the size of the crystal on the film emulsion O The smaller the size of the crystal the sharper the radiographic image 9 The larger the crystal the less sharpness on the film IV Rules for Casting a Shadow Image A Rules are needed because we are taking a radiograph of a 3 dimensional image on a 2 dimensional film B 5 rules to consider when exposing a radiograph 0 U 11gt DJ 0 U m 11 Small focalireduces the size of the penumbra Long targetobject distanceireduces penumbra and magni cation Short object lm distancereduce penumbra and magni cation Object and lmimust be parallel to prevent distortion Central ray of the xray beam must be perpendicular to the object and the lm to prevent distortion Magni cation l The increase in size of the image on the radiograph compared to the actual srze 2 Mostly in uenced by the target object distance and object lm distance 3 Determined by the PID 4 With a long PID the object lm distance should be kept to a minimum 5 Increasing the targetobj ect distance and decreasing the object lm distance will minimize image magni cation and increase image sharpness Distortion l The result of unequal magni cation of different parts of the same object 2 Refers to the true size and shape of the object being radiographed 3 Results when the lm is not parallel to the object And when the central ray is not perpendicular to the object and lm 4 To minimize image distortion position the lm parallel to the tooth and align the central ray perpendicular to the tooth and lm Effects Varying the Control Factors 3 control factors to consider 1 milliamperage 2 exposure time 3 kilovoltage Whenever one is altered a combination of factors must be proportionally altered to maintain radiographic density Variations in Milliamperage 1 Density of radiograph determined by dentist 2 Increasing the mA s increase the darkness of the radiograph 3 Decreasing the mA lightens the density of the radiograph Variations in Exposure Time 1 The main effect is on the density of the radiograph 2 Increasing the exposure time darkens the radiograph 3 Decreasing the exposure time lightens the radiograph 4 Easiest factor to control 5 If machine is xed exposure time is the only factor that can be controlled Since both millamperage and exposure time control the density only one of them is changed at a time Variations in kilovoltage 1 Quality of radiation is determined by the kVp 2 When increased the number of xrays is also increased Therefore the number of xrays hitting the lm is increase This then increases the density of the lm UIbUJNt I VI VII 11gt DJ 0 U 003 gt U 3 Too dense of a lm black is not acceptable therefore if kVp s are increased then either the mA or exposure time must be decreased Effects of variations in Distances 3 distances the operator must take into consideration 1 distance between the xray source and the surface of the pt s skin 2 Distance between the tooth and the lm 3 Distance between the source and the film Targetsurface skin distance 1 Determined by the length of the PID 2 All techniques require that the PID be as close to the skin as possible 3 Standards have been set for the PID a 7 for machines at 50 kVp or above b 4 for machines at 50 kVp or below c Extraorally the distance is 72 Objectfilm distance 1 Depends on method being used by the operator 2 Bisecting a Requires that the film be next to the tooth b Results in the object film distance being shorter in the area of the crown c Least divergence occurs in the mandibular molars d Greatest divergence is in the maxillary anteriors 3 Paralleling a Most attachments are made to hold the film parallel to the long axes of the tooth Film must be positioned sufficiently to the li of the teeth to avoid impinging on the supporting structure c Results in objectfilm distances that are often more than 1 Targetfilm Distance 1 The sum of the targetobj ect and objectfilm distance 2 The quality of the xray improves whenever the targetfilm distance is increases 3 Sharpness increase while penumbra decreases 4 The location tube within the tube housing makes a difference in the target film distance 5 When the tube is recessed enough space is gained within the tube head so that a long targetfilm distance is achieved with a short PID see the dental clinic Inverse Square Law Definitionithe intensity of radiation varies inversely as the square of the distance from its source May be written as see board Is used when we consider distance as a means of protection and the length of the PID mAsdistance relationship 1 The intensity of the beam is reduced unless a corresponding increase is made in one or a combination of the exposure factors 2 Necessary to make theses changes to maintain diagnostic radiographs U 3 MA s distance relationship must be changed also see board E Exposure charts VIII Application IX Evaluation at a later date DEA 125 Radiology I Effects of Radiation Exposure At the completion of this lesson the student will with at least 70 accuracy on a written andor oral exam and 100 accuracy on a performance evaluation 1 De ne key words 2 Compare the theories of biological damage and the possible effect of radiation on somatic and genetic cells Identify the body of cells in the order of their radiosensitivity Identify the factors that determine radiation injuries List the sequence of events that may follow exposure to radiation Identify the three areas in the head and neck that are most affected by radiation List the possible short and long term effects of irradiation 8 Discuss the risk versus benefits of dental radiation therapy 05 er gt1 I Introduction A Radiation has the ability to detach and remove electric charges from the complex atoms that make up the molecules ofbody tissues B This process creates an electrical imbalance within the normally stable cells This process is known as ionization C During ionization the balance of cell structure is altered and the cell may be damaged or destroyed II Concerns with Potential Radiation Effects Patients are concerned with safety as well as the federal government 1 19817passage of the ConsumerPatient Radiation Health and Safety Act due to the Three Mile Island accident Some concern is warranted but a lot is unsubstantiated Radiation can occur either naturally or be manmade Most somatic body cells have a recovery rate of 75 win the lSt 24 hrs D The most important thing the operator must consider when exposing radiation is the quantity and the duration of the exposure and the body area to be exposed 003 N E Radiation exposure is accumulative w ea Exposure increasing the negative effects F Radiation may also alter the genetic material in the reproductive cells so that mutations may occur G There have been no reports of radiation injuries caused by normal dental radiagraphs JD DEA 125 RADIATION EXPOSURE III Theories of Biological Effects Mechanisms A Two Theories l Directhit or target theory 2 Indirect action or poison water theory 3 Regardless of which theory you believe in the nal outcome is that radiation damages tissue B Direct Hit Theoryixrays photons collide w important cell chemicals and break them apart by ionization and causes damage to lg molecules C Indirectactionibased on the assumption that radiation causes damage to the cell by ionizing the water within the cell IV Cell Sensitivity to Radiation Exposure Cells are most sensitive during mitosis B Not all cells are equally sensitive to radiation C The Law ofB and T 1 States the radiosensitivity of cells and tissues is directly proportional to their reproductive capacity and inversely proportional to their degree of differentiation 2 lSt half of law states that actively dividing cells such as white blood cells are more sensitive than slowing dividing cells 3 2quotd half oflaw states the more specialized a cell is the more radioresistant the cell 4 Based on this law we can rank cells in descending order of radiosensitivity 5 Lymphocytes erythrocytes and immature reproductive cells are highly sensitive while nerve cells brain cells and muscle cells are low sensitivity D Doseresponse curve 1 Plotting the dosage administered with the response or damage produced 2 This plot is called the doeresponse curve 3 Difficult to determine the radiation effects at low levels of exposure 4 Therefore it is based to take the conservative approach and consider all radiation is damaging 5 ALARAithe concept that guides all safety guidelines in dentistry V Determining Radiation Injury 8 factors determine the amount of radiation injury total dose dose rate area exposed variation in species individual JD DEA 125 RADIATION EXPOSURE sensitivity variation in cell sensitivity variation in tissue sensitivity and age B Total doseitotal dose depends on the type energy and duration of radiation The grater the dose the more sever the probable biological effect C Dose rateithe rate of administration or absorption is important in determining what effects will occur Less damage will occur if the total amt of radiation is spread out over a longer period of time instead of giving a lg amt all at one time This principle is used to determine the amt to be given during radiation treatment D Area exposedithe larger the area exposed the greater the damage E Variation in speciesivariation in radiosensitivity between different species F Individual sensitivityiEach species has their own lethal dose Lethal dose LD is expressed as 5030 or the dose required to kill 50 of the individuals in a lg population in 30 days For humans it is est to be 45 Grays or 450 rads G Variation in cell sensitivityirapidly dividing cells are more sensitive to radiation than those that do not divide H Variations in tissue sensitivityisome tissues are more radiosensitive than others In dentistry the critical areas are the lens of the eye and the thyroid gland I Ageiyounger more rapidly dividing cells are more radiosensitive than older mature cells Therefore children and pregnant women will be more sensitive VI Events Following Radiation Exposure A Sequence of events Latentifollowing the initial radiation exposure and before the first detectable effects occurs Can be a very short or extremely long period 2 Period of injuryifollows the latent period at this time certain effects can be of served The most common effect seen is the stoppage of mitosis This can be either temporary or permanent Another effect that can be seen is the breaking of chromosomes abnormal mitosis and formation of giant cells 3 Recovery periodisome recovery does happen This is considered shortterm effect If no recovery occurs then is it irreparable injury or longterm effect B Short Term Effects 1 Those effects that are seen minutes days or months after exposure 2 In dentistry shortterm effects are usually not seen JD DEA 125 RADIATION EXPOSURE 3 If a pt receives over 10 grays wholebody in a short period of time the effects collectively are known as the acute radiation syndrome ARS 4 Symptoms include nausea vomiting diarrhea hemorrhage and hair loss C Longterm Effect Those effects seen yrs after the original exposure 2 From the public health point of view this is what we should be concern with in dentistry 3 Most longterm effects have mostly been somatic damage 4 Longterm effects may also include increased incidence of cancer embryological defects cataracts lifespan shortening and genetic mutations 5 The first 4 are somatic and only involve the individual being exposed D Risk Estimates 1 Defined as the likelihood of injury or death from some hazard 2 For dental radiography the risk is radiationinduced cancer 3 The questions that must be asked every time is Is the risk greater than the bene t VII Effects of Oral Radiation Therapy A The exposure used in dentistry is so minimal that unless repeated hundreds of time in rapid succession it will be virtually impossible to create the conditions mentioned B During radiation therapy of 6 wks or greater the pt may receive doses of 2 grays daily for 5 dayswk at eh site of the malignancy for a localized dose of 60 grays Most radiation treatment is local dose NOT whole body dose Oral radiation is being used more frequently in the treatment of oral cancer E The dental team should be aware of complications that can happen with oral radiation for cancer F Complication can be seen any time after the initiation of radiation therapy up to 5 yrs post treatment G Complications are in three stages acuteiduring the first 6 mos of treatment subacuteiduring the second 6 mos 3 chronic clinical periodifrom the end of the second 6 mos through the fifth yr H An increase of discomfort and emotional stress is experienced by the pt during the acute stage UO Ni JD DEA 125 RADIATION EXPOSURE I Complications include sensitivity and discomfort to the touch in and around the mouth lost of appetite and sense of taste saliva is thick and ropy xerostomia dysphagia the tongue maybe swollen along with the throat feeling congested J The major concern is what to do when the need arises to expose the pt is dental radiographs during those rst 5 years VIII Evaluation Written test at a later date JD DEA 125 RADIATION EXPOSURE


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Anthony Lee UC Santa Barbara

"I bought an awesome study guide, which helped me get an A in my Math 34B class this quarter!"

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"


"Their 'Elite Notetakers' are making over $1,200/month in sales by creating high quality content that helps their classmates in a time of need."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.