Module 5 Flashcards
Intra Oral techniques - Bitewing:
Modern:
- holder with aiming ring
Original:
- Wing or tab
Taking a bitewing radiograph:
1) is it an adult or child?
The normal size is 31x41mm - small is 22 x 35mm
- film
- solid state sensor
- photostimulable phosphor plate
2) position patient
head supported with the occlusal plane horizontal
3) position film/holder
lingual sulcus
distal of lower canine to the mesial aspect of lower third molar
receptor and teeth as close as possible
4) patient to close teeth on bite platform
Beam angulation (BW):
- beam indicating device should be used
- centre this on receptor
- beam meets teeth and receptor at right angles (90 degrees)
- beam passes through all contact points
- beam aimed downward approximately 5-8 degrees
Choose settings (BW):
- think about cross infection
- patient preparation:
- Explain procedure
- Check ID
- Check radiographic views required
- Remove dentures, appliances etc
- expose:
- Patient in full view, ensuring they don’t move throughout the exposure
Advantages and Disadvantages for BW:
Advantages:
- Simple and straightforward
- Difficult for tongue to displace the receptor
- Beam aiming device determines angulation
- Cone cutting avoided
- Autoclavable/disposable holders
Disadvantages:
- Not 100% reproducible
- Uncomfortable for patients
- Expensive holders
Radiographic Features (Bw):
- Crowns
- Enamel
- Dentine
- Pulp chamber
- Coronal part of root
- Alveolar crests
- Lamina dura
- Periodontal ligament space
Additional features (Bw):
- Floor of antrum
- Carious cavity
- Calculus
- Unerupted/developing teeth
- Restorations
- Pulp stones
- Airspaces
Ideal Quality criteria (BW)
- no distortion or blurring
- no coning
- no overlap of approximal surfaces
- include mesial surface of first premolar to distal surface of second molar
- geometrically comparable to previous bitewing
- occlusal plane in the middle of the image
- buccal and lingual cusps superimposed
Ideal quality criteria - density and contrast (Bw)
Caries and restoration assessment:
- well exposed
- good contrast
- differentiation between enamel and dentine
- ADJ will be seen
Periodontal status
- under exposed
- avoid burn out
- vertical bitewing
Technique errors (Bw)
- Receptor positioned too far posterior =
no premolars - Receptor incorrectly placed =
displacement of receptor by tongue, distortion - Incorrect beam alignment in horizontal plane =
too far posterior or anterior - coned off
not aimed through contact areas - overlapping - Incorrect beam alignment in vertical plane =
no superimposition of buccal and lingual cusps - incorrect exposure settings =
overexposed - burn out - poor contrast - dark image
underexposed - poor contrast - pale image - movement of patient or BID
blurring
Quality assessment - technique (Bw)
assess the following:
- Are all required teeth shown?
- Are the crowns of upper and lower teeth shown?
- Are the contact areas overlapped?
- Are the buccal and lingual cusps superimposed?
- Has there been any cone cutting?
- Is the occlusal plane horizontal?
- Is it geometrically comparable to previous films?
Quality - exposure factors (Bw)
- Is the image too dark?
- Is the image too pale?
- is the amelodentinal junction apparent?
- what effect has exposure had on the structures shown?
- is any cervical burn-out noticeable?
Periapical Radiography (PA)
Includes:
Paralleling or bisecting angle techniques
Coverage 2-4 teeth
Individual teeth:
- apical areas
- detailed view of tooth and alveolar bones
Clinical indication (PA)
- Apical infection/inflammation
- Assess periodontal status
- After trauma - check teeth and bone
- Presence and position of unerupted teeth
- Root morphology prior to extraction
- Endodontic progression
- Evaluate apical cysts or other alveolar bone lesions
- Post operative evaluation of implants
Geometric requirements (PA)
- Tooth and film in contact or as close as possible
- Tooth and film packet parallel
- Beam meets tooth film at right angles, beam should be at right angles in both planes (horizontal and vertical)
Paralleling technique (PA) practical technique
- Receptor positioned in holder, placed with the long axis
- vertical for incisors and canines
- horizontal for molars and premolars - Ensure enough film beyond the apex to record the tissue in this area
- Holder needs to be positioned so that the tooth to be x-rayed is touch bite block, may need to use a cotton wool roll
- Patient to bite together
- Locate ring should be just touching the patients face
- Align the spacer cone with the ring
- Ensure patient is still and make the exposure
- This should be a reproducible position
Image positioning variations (PA)
Maxillary incisors and canines = -Accommodate height of palate -Posterior position Mandibular incisors and canines = -In floor of mouth -In line with lower canines or premolars Maxillary premolars and molars = -In midline -Accommodate height Mandibular premolars and molars -Lingual sulcus -Next to appropriate teeth
Patient care(PA)
- Justification
- Patient identification
- Explain procedure
- Remove appliance/dentures
- Set exposure parameters
- Patient positioning
- Head support
- Occlusal plane horizontal
- Check required view
- Position receptor
- Align beam
- Make exposure
Cross infection control =
- PPE
- Barriers
- surfaces
- receptors
- Disinfection
- Hand washing
- Clinical waste
Radiographic features of the MAXILLA
CENTRAL INCISORS:
- shadow of top of nose
- trabecular bone pattern
- lamina dura
- median suture
- gingival soft tissue
- periodontal ligament space
- pulp canal
- restorations if present
CANINES:
- trabecular bone pattern
- lamina dura
- periodontal ligament space
- pulp canal
- overlapping crowns
- superimposed roots of first premolars
- restorations if present
PREMOLARS:
- trabecular bone pattern
- lamina dura
- periodontal ligament space
- intercrestal bone
- pulp canal
- restorations if present
- floor of antrum
- maxillary antrum
MOLARS:
- trabecular bone pattern
- lamina dura
- periodontal ligament space
- intercrestal bone
- pulp canal
- restorations if present
- floor of antrum
- maxillary antrum
- zygoma
- unerupted 3rd molar
Radiographic features of the MANDIBLE
INCISORS:
- enamel
- periodontal ligament space
- upper margin of the lower lip
- lamina dura
- trabecular bone pattern
CANINES:
- enamel
- pulp canals
- periodontal ligament space
- orientation dot
- lamina dura
- bone pattern
- burn out
PREMOLARS:
- lamina dura
- bone pattern
- pulp canals
- mental foramen
MOLARS:
- interdental bone
- varying bone patterns
- inferior dental canal
- developing third molar
Ideal quality criteria(PA):
- no distortion or blurring
- include correct anatomical area with apices and 3-4mm of surrounding bone
- no overlap of approximal surfaces
- no coning off
- geometrically comparable with previous periapical images
DENSITY AND CONTRAST:
caries, restorations, periapical assessment:
- well exposed
- good contrast
- differentiation between enamel and dentine
- differentiation between periodontal ligament space
periodontal status:
- under exposed
- avoid burn out
Preparation, positioning and technique errors: (PA)
Dentures and appliances not removed - superimpositions Incorrect position of receptor - not over the area of interest - no apicies or periapical tissues - bending - distortion Incorrect orientation - no image (back to front) Poor alignment of BID - horizontal - cone cutting, overlapping contact areas - vertical - cone cut, foreshortening, elongation Poor communication - movement, blurring Incorrect settings - poor contrast Double exposure - receptor used twice
Considerations for PA:
- children and disabled
- anatomical difficulties
- neurological difficulties
- radiographic investigations appropriate to the limitations
- appropriate film size
- modify technique
- assistance
- under GA
- avoid OPG
- paralleling technique preferred
Positioning when doing Bisected angle technique:
PATIENT:
- seated
- head supported
- occlusal plane parallel to floor
- bite gently or slight support with thumb or index finger
IMAGE RECEPTOR:
- orientate
- as close to tooth as possible
- do not bend
- tube head placed dependent on tooth for investigation
- assess vertical angle
- beam 90° to bisected angle
- horizontal angle through interproximal areas
Vertical angulation (PA):
Maxilla - downwards angulation: INCISORS - 45° to bridge of nose CANINES - 50° PREMOLARS - 40° MOLARS - 30°
Mandible - upwards angulation: INCISORS - 25° CANINES - 20° PREMOLARS - 15° MOLARS - 5°