Date post: | 06-Apr-2015 |
Category: |
Documents |
Upload: | amany-suliman |
View: | 128 times |
Download: | 1 times |
Caries
Bitewing Film primarily
Periapical film also used
Low kVp, high contrast
(short scale)
Approximately 50 % demineralization is required for radiographic detection of a lesion. As seen in the occlusal view, above right, the thickness of the tooth buccolingually masks the carious lesion when it is small.
The actual depth of penetration of a carious lesion is deeper clinically than radiographically.
Proximal caries susceptible zone (between contact and free gingival margin)
caries
Factors affecting caries diagnosis:
Buccolingual thickness of tooth
Two-dimensional film
X-ray beam angle
Exposure factors
Radiographic Caries
I
M = Moderate I = Incipient
A = AdvancedS = Severe
S
AMA
Usually not restored unless patient has high caries activity
IncipientInterproximalCaries I
Up to half the thickness of enamel
Incipient
ModerateInterproximalCaries M
More than half-way through the enamel (up to DEJ)
Moderate
AdvancedInterproximalCaries AA
From DEJ to half-way through the dentin
Advanced
Advanced
Advanced
Advanced
IncipientModerateAdvanced
SevereInterproximalCaries
More than halfway through the dentin
S
Green arrows identify restorative problems: fx (1), overhang (2), open margin (3)
3
21
Severe
Severe
Anterior interproximal caries can usually be diagnosed by directing bright light through the contact areas.
Transillumination
Must have penetrated into dentin
Diagnosed from clinical exam
Sharp explorer may contribute to spread of caries
Occlusal Caries
Occlusal
Occlusal
Use clinical exam
Can’t determine depth
Buccal/Lingual Caries
Buccal/lingual
Older patients with recession or periodontitis
Xerostomia may be present
Root Caries
Root caries
Root caries
Cervical Burnout
Root caries may be confused with cervical burnout (see below).
Cross-section(red line at right)
Radiolucency seen above left (arrow) disappears on periapical film of same tooth (above right).
Cervical burnout
Anterior Cervical Burnout
bone level
cervical burnout area
Cervical burnout in the anterior region due to gap between enamel (red arrows) and alveolar bone over root (blue arrows).
May be due to high caries rate, poor oral hygiene, failure to remove all the caries, defective restoration or a combination.
Recurrent Caries
Recurrent caries(red arrows)
Recurrent caries
Recurrent caries
Rampant Caries
Rapidly progressing caries usually found in children and teens with poor diet and inadequate oral hygiene
Found in head/neck radiation therapy patients with xerostomia
Fluoride used for control
Radiation Caries
Before radiation
1 year after radiation
Mach BandOptical illusion giving appearance of increased radiolucency at junction of differing tissue densities
Bitewings best for diagnosis. Some feel that paralleling PA’s are best.
Higher kVp recommended (long scale, low contrast).
Compare images from differentvisits (using same technique).
Periodontal Disease
Two-dimensional film with overlapping bony walls, superimposed roots
Clinical picture more advanced
Relationship of hard to soft tissues not evident
Limitation of Radiographs
Involvement:
LocalizedGeneralized
Periodontitis
Periodontitis
Normal Anatomy:
Alveolar crest corticated
1-1.5 mm from crest to CEJ
Parallel to line between CEJ’s
Crest is pointed anteriorly
Corticated alveolar crests
1-1.5 mm
CEJ
Alveolar crests morepointed anteriorly
Contributing Factors• Occlusal trauma• Open contacts• Overhangs, poor contours• Calculus• Post-extraction defects (interdental
col)• Systemic involvement (diabetes, blood disorders, hormonal changes, stress, AIDS)
Horizontal bone loss: Parallel to line drawn between adjacent CEJ’s
Vertical (Angular) bone loss: More bone destruction on interproximal aspect of one tooth than on the adjacent tooth
Gingivitis
No bone loss
No radiographic signs
Mild Adult Periodontitis
Loss of cortical density
Rounding off of junction between alveolar crest and lamina dura
Blunting of crest anteriorly
Mild adult periodontitis
Horizontal bone loss or vertical osseous defects
Total extent of bone loss not evident
May have slight mobility
Moderate Adult Periodontitis
Moderate adult periodontitis(red arrows point to calculus)
Moderate adult periodontitis
Severe Adult Periodontitis
Tooth mobility
Extensive horizontal bone loss or vertical osseousdefects
Furcation involvement
Severe adult periodontitis
Severe adult periodontitis
Severe adult periodontitis
Restorative Materials• According to radiographic density beginning
with most radiopaque• Group I. Gold alloys, amalgam,silver• Group II. Gutta percha, zinc oxyphosphate or
other base materials, composite with opacifier, rubber base impression material, calcium hydroxide with opacifier
Group III. Porcelain Group IV. Radiolucent. Calcium hydroxide,
composite, resin
Gold crowns, amalgams
Retention pins
porcelain crowns
crownamalgam
crown
silver pointsgutta percha
cast post
Red arrows point to basesGreen arrow indicates recurrent caries with fractured restoration
Compositesold new
Clinic
Procedures
When you report to the Radiology Clinic, take the signed chart to the reception desk. The desk person (usually Kisha, seen at left) will dispense the necessary films, a film bag and paralleling periapical instruments.
After being assigned to a cubicle by an instructor, check to make sure it has been properly prepared. This will usually be taken care of before you get to the cubicle. If not, trays with the necessary barrier materials are available.
tubehead cover
headrest cover exposure switch cover
rubber bandpaper towel
Cubicle Preparation
Cover the appropriate equipment as indicated by the labels above. The rubber band is used to tighten the plastic around the PID on the tubehead. The paper towel is used to dry films as you take them.
Seat the patient. Adjust the headrest so that it supports the head properly. Raise or lower the chair as needed.
If you have not reviewed the patient’s medical and dental history, identify the following:
1. Is the patient pregnant
2. Does the patient have any symptomatic teeth
3. Have dental x-ray films been taken recently.
Films will normally have been ordered before coming to the Radiology Clinic. After seating the patient, if you have not already done so, check the patient’s mouth before starting to take films. A patient may have missing teeth (spaces open or closed), very small teeth, etc., and you may be able to eliminate some of the films. Consult with the instructor.
BEFORE PATIENT
1
2
3
PAPERWORK
PAPER FILM BAG
FILM & RINNS
PLACE ON LOWER COUNTER
OPEN & PLACE ON TOP COUNTER BEHIND TRAY
EMPTY FILMS FROM PLASTIC BAG ONTO TRAY; EMPTY RINN
INSTRUMENTS (BW &/OR PA) FROM POUCH ONTO TRAY
SEAT PATIENT
4
5
6
LEAD APRON
HEAD REST
HAND GEL/GLOVES
PLACE WITHOUT GLOVES
ADJUST TO SUPPORT HEAD
CLEAN HANDS AND PUT ON GLOVES
7
8
9
10
WITH GLOVES ON...
RINNS
FILMS
UNWRAPPED AREAS
CLINASEPT
ASSEMBLE INSTRUMENTS (SEE PICTURES AT LEFT)
DOT-IN-SLOT AND WHITE SIDE FACING RING (SEE PICTURES)
DO NOT TOUCH (SEE # 18)
TEAR OPEN CLINASEPT BARRIER AND DROP FILM INTO BAG
WITHOUT TOUCHING EITHER FILM OR BAG
AFTER LAST FILM PATIENT SEATED WITH APRON ON; GLOVES STILL ON
11
12
13
14
15
16
17
BARRIERS
RINNS
PAPER TOWEL &
COTTON ROLLS
GLOVES
HAND GEL
LEAD APRON
DISMISS PATIENT
REMOVE; DISCARD PLASTIC BAGS AND RUBBER BAND
TAKE APART; LEAVE ON TRAY
DISCARD
REMOVE AND DISCARD
CLEAN HANDS
REMOVE (WITHOUT GLOVES)
SEAT IN RECEPTION AREA; HAVE PATIENT REMOVE
EARRINGS, NECKLACE, ETC., IF PAN NEEDED
CUBICLE CLEANUP
18
19
20
21
22
DISINFECT
CUBICLE
TRAY & RINNS
GRADE SHEET
PAPER FILM BAG
DISINFECT AREAS TOUCHED WITHOUT BARRIERS
INSPECT FOR TRASH ON FLOOR, ETC.
TO CUBICLE F; RINNS IN SINK, TRAY ON LOWER COUNTER
PLACE BY VIEWBOXES IN BACK ROOM
TAKE FILM BAG TO DARKROOM
Place the instrument(s) and films on the tray. You can dump the films and instruments out of their bags onto the tray, but don’t touch them. Set up the film bag off of the tray so that it is ready to receive the films as you take them.
The next step is to place the lead apron/thyroid collar on the patient. The velcro pad (green arrow) should face you as you place the apron on the patient. Secure the apron by taking the strap behind the patient’s neck and securing it to the pad. Then position the thyroid collar (yellow arrow) using the velcro attachments.
Wash your hands and put on gloves. We use vinyl gloves, with extra small, small, medium, large and extra large sizes available. Gloves must be worn when handling films or assembling instruments.
The “instant hand antiseptic” seen at right may be used in place of washing the hands, assuming your hands are not visibly soiled. This is available in each cubicle.
You are now ready to assemble the instruments and take the films on the patient. Always start with the more anterior films. If you are doing a full series, start with the anterior periapicals, then do the posterior periapicals (premolar then molar in each quadrant) and finish with the bitewing films. When taking bitewings, always do the premolar film before doing the molar film. (Review technique lectures so that you will be prepared).
Criteria for Radiographic Exposure:
Only those films considered necessary for a proper diagnosis will be ordered.
Recent films (within six months) taken by an outside dentist should be requested for evaluation prior to ordering new films. Potential inferior quality of duplicates should be mentioned to patient.
The pregnant patient should be exposed to x-rays only for the information that is diagnostically required for planned treatment during pregnancy.
Criteria for Radiographic Exposure:
The lead apron and thyroid collar will be used on all patients for intraoral films. The lead apron only (no thyroid collar) is used for panoramic films.
The operator must stand behind the barrier provided for each cubicle. The operator must observe the patient through the leaded glass window during the exposure of each film.
• Universal precautions: Protect patient and operator from cross- contamination
• Cover x-ray tubehead, exposure switch and headrest with plastic
• Place lead apron (no gloves)
• Empty instruments/films onto tray
• Clean hands before gloving
Infection Control
• Do not touch anything but films, instrument, patient, and covered x-ray equipment with gloves on
• Don’t wear gloves outside cubicle
• Dry film packet, remove film from Clinasept. DON’T TOUCH FILM
Infection Control
• After completing films, remove plastic and disassemble instruments
• Remove gloves and clean hands with alcohol gel or soap/water
• Remove apron
• Disinfect if needed (Wipe those areas that were touched and not covered with plastic)
Infection Control
Panoramic machine:
• Use gloves when placing and removing bitestick cover
• Wipe down bitestick, chin rest, forehead positioner and lateral head positioners with Birex
Infection Control
Object Localization
Radiographic Definition Closer to film = sharper
Right-Angle Technique (Occlusal) Buccolingual location
Buccal Object Rule (SLOB) Two films; different horizontal or vertical angulations
Radiographic definition
Right Angle (Occlusal) technique
Two films are needed. There must be a change in the horizontal or vertical angulation of the x-ray beam to get movement of the image of the object on the film.
Buccal Object Rule
Same Lingual Opposite Buccal(Compares object movement with tubehead movement)
When using the SLOB rule, the direction of the beam must be opposite to the way the tubehead is moved.
Horizontal Tube Shift: When the tubehead is moved mesially, the beam must be directed more distally (from the mesial). If the tubehead is moved distally, the direction of the beam must be more towards the mesial (from the distal).
Vertical Tube Shift: The SLOB rule also works for movement of the tubehead in a vertical direction. When the tubehead is raised, the beam is directed down and when the tubehead is lowered, the beam is directed upward.
Buccal Object Rule
Same Lingual Opposite Buccal(requires two films)
incisors
canine
premolar
molar
Horizontal movement of the x-ray beam
Maxillary PA
BW
Mandibular PA
Vertical movement of the x-ray beam
tubehead
canine premolar
restoration
Tubehead movement
premolar molar
Lingual object
Buccal object
molar premolar
tubehead
canine
tubehead
premolarcanineincisor
tubehead
tub
ehead
BW
PA
tub
ehead
BW
PA
X-ray machine
Sensor
Computer
Monitor
Printer
Digital Radiography
X-ray Machine
Low kVp (70), mA (5)
Accurate timer
Small focal spot
DC circuit
Underexposure Graininess
Sensors CCD: Charged Coupled Device CMOS: Complimentary Metal Oxide Semiconductor
Real Time Imaging (Direct)
Wired (most common) or wireless
Image Receptors
Pros “Instant” image Better resolution More durable Cons Rigid and thick (3 to 8 mm) Expensive ($5,000 to $14,000) Most have wire connecting sensor to computer
to computer
CCD, CMOS
Plates PSP: Photo-stimulable Phosphor Laser scan (Indirect)
Requires reduced lighting when scanning sensor plates
Images erased by exposure to light before reusing plate
Image Receptors
Sensor Plastic sleeve
PSP
PSP: Photostimulable Phosphor
Pros Patient friendly; no change in technique More film sizes to choose from Plates relatively inexpensive ($35+) Wider exposure latitude
Cons Easily damaged More time consuming (laser scan) Less resolution
Use paralleling, bisecting angle or bitewing technique. Biteblocks are different for the direct sensors, but rest of instrument is the same.
Biteblocks for CCD, CMOS
Regular Rinn instruments for PSP
Both Direct and Indirect digital systems have panoramic and cephalometric applications. The direct is much more expensive.
Computer
2+ GHz Pentium 4 with 256 MB RAM
Large storage capacity hard drive Periapical = 300-400 KB Pan/ceph = 4-7 MB
CD/DVD writer
Laptop optional
Monitor
CRT for radiographic interpretation
LCD flat panel for patient presentation
Best for color, such as photos
Contrast ratio of 400:1
Dpi less than 0.27 mm
Printer
Diagnosis made on monitor
Good quality ink jet or dye sublimation
Photo quality paper
Digital Radiography Advantages
• Reduced patient exposure (60-90%)
• Ability to enhance image
• Improved patient education
• “Instant” image (CCD, CMOS)
• Better workflow (CCD, CMOS)
Digital Radiography Advantages
• Environmentally friendly (no lead, silver)
• No darkroom errors
• Improved archival quality of images
• Easier transfer of information
(continued)
Cost comparison
New practice: digital cheaper
Ongoing costs: digital cheaper
CCD/CMOS system cheaper than PSP when buying only one sensor
Check warranty costs
Practice Management Software
Most systems compatible but check to make sure DICOM compliant digital software; better digital image management and sharing of information
Application Service Provider
Store images on Internet site
Small monthly service fee
“Chat” rooms (password protected)
Scanners
Archive current films
Manipulate digital image of films to “recover” information
Send information to insurance carrier
Case presentations
Probably not worth time/cost