main points Flashcards
types of intraoral views
- bitewings
- periapicals
- occlusals
types of extra oral views
- panoramics
- Cone Beam CT
what is radiolucent and radiopaque
radiolucent: beam is less attenuated - appear darker
radiopaque: beam is more attenuated - appear lighter
what bitewings are for
- interproximal caries of posterior
- alveolar bone level
triangular radiolucency at CEJ
Cervical Burnout
explain phenonmenon of cervical burnout
- radiolucent at CEJ
- increased X-ray penetration in the neck of the tooth due to its anatomical shape and decreased density
radiopauqe zone under amalgam
due to Sn & Zn ions releasing into demineralised dentine
whats Mach Band Effect
- optical illusion by retina
- bright areas look brighter, dark looks darker
- misleading
caries appearance in dentine and enamel
enamel: triangular
dentine: fuzzy, ill-defined margin
usage of PAs
- periapical pathology
- bone leves of single tooth
types of upper and lower occlusal views
upper
- anterior oblique maxillary
- lateral oblique maxillary
lower
- true mandibular occlusal
- anterior oblique mandibular
what type of view
anterior oblique maxillary
what type of view
lateral oblique maxillary
what type of view
true mandibular occlusal
description of lesion
- site
- estimated size/ extent
- shape
- margins/ outine (corticated)
- surrounding structure and affect
- unilocular/ multilocular
- radiodensity
curve of spee/ wilson
spee: occlusal curvature
wilson: curvature across arch curvature
What does ALARP stand for
as low as reasonably practicable
guidance on using x-ray safely
Faculty of General Dental Practice
OPT full name
orthopantomogram
whats tomography
slices of image - no overlapping
OPT receptor and x-ray beam position
receptor in front
x-ray beam behind
focal trough
- structure on it will appear clearly
- tomographic slice of interest
- thinner at the incisor region
- anything out of “normal” dental arch will be blurry
OPT limitation/ contraindication/ disadvantages
- longer expoure time (Mobility eg parkinsons )
- ectopic tooth out of focal trough
- more superimposition/ artefacts
- worse clarity
- higher radioation dose (5x more than PA)
- anterior superimposed by cervical spine
OPT advnatages
- capture full dentition
- capture non-dental areas (condyles /max sinus/ rami)
- no need of intra-oral holders (gaggers/ children/ trauma)
how to adjust OPT for better view for interdental bone loss and IP caries?
Orthogonal program
OPT - structure lingual/ buccal to focal trough magnified more?
Lingual
- as x-ray beam is from behind ot (lingual)
- more time under x-ray
OPT - whats the verticl angulation of beam
- 8 degree above horizontal
- angled upwards
-to reduce superimposition of hard palate
estimation of effective dose of each radiographic view
unit: Micro Sieverts
OPT - how to reduce radiation dose
field limitatio eg half / mid face OPT
OPT- what happen if pt chin down/ up
down: smiling occlusal plane
up: flat occlusal plane
OPT - what happen if mid-sagittal plane not centred
distortion of one / both side
OPT what happen if pt slumped
excessive cervial spine shadow
OPT- what happem if pt stand too back/forward
Blurry (out of focal trough)
front : incisors appear narrower
back: incisors appear wider
Ghost shadow appearance
- magnified
- blurry
- higher
- opposite side
selection criteria is based on
selection criteria for dental radiography by the FGDP (Faculty of General Dental Practice UK)
OPT selection criteria FGDP
only when presence of specific clinicla signs and symptoms - not routine screening
some OPT indication
- generalised caries
- perio bone assess (not ideal anteriors)
- bony lesion (cyst )
- 3rd molar
- ortho assessment
- mandibular #
- max sinus pathology
- TMD
- pre-implant planning
PA vs OPT
adv of each
Pa
- higher resolution
- greater for anterior
- capture in split second (less movement artefact)
OPT:
- more anatomical structure shown
- lower dose than full mouth PA
- no intra oral receptors (gagging)
- less time consuming
bitewing vs OPT
adv of each
bw:
- higher resolution
- Good for IP caries (less overlapping)
- lower dose (if L+R)
OPT
- show periapical region
what lateral ceph good for?
- relationship of jaws
- angulation of ant teeth
- ortho assessment
CBCT advantages
- 3 D images
- looking at diff angles
- multiple slices
possible pathology of pa radiolucency
- Periapical Abscess
- Periapical Granuloma
- Radicular (Periapical) Cyst
- Osteomyelitis
- Traumatic Bone Cyst
- Pulpal Necrosis
possible causes of widening of PDL (w/o PA radiolucency)
- Occlusal Trauma
- Early Stage of Infection or Inflammation
- Orthodontic Movement treatment.
- Traumatic Injury
- Systemic Diseases
