Dentals - Intra-Oral Flashcards
what are the radiographic views for intra-oral ? - 3 points
peri-apicals
bitewings
occlusals
what are the radiographic views for extra-oral? - 4 points
dental panormaic tomographic (OPGs)
cephalometry
lateral oblique jaw
CBCT
how many teeth do most people have when fully developed?
32
when do teeth begin to erupt
6 years old
when have most permanent teeth erupted by?
12 years old
wisdom teeth are the exception, when do these appear?
late teens / early twenties
what are the order of teeth and how are they classified?
incisors - central and lateral
canines - cuspids
pre-molars - bicuspids
molars
what is hypodontia?
where teeth are missing as they never erupted
describe the dental pulp - 6 points
innermost part of the tooth
soft tissue rich with blood vessels and nerves
responsible for nourishing the tooth
pulp in the crown of the tooth is known as the pulp chamber
pulp canals transverse the root of the tooth
typically sensitive
why are peri-apicals taken? - 2 points
to image the whole of the tooth including the bone around the apex of the root
to get detailed information about a selected tooth - e.g. in cases of tooth ache
what is used in a peri-apical?
what else can be used?
intra-oral plates, a plate folder, a digital processor
intra oral sensor
what are the two techniques that can be used to acquire a peri-apical image?
parallelling technique
bisecting angle technique
why is a paralleling technique required?
the plate and tooth should be parallel to each other and close together - difficult because of shape of mouth
what is the paralleling technique?
using anterior/posterior/bitewing holders to make the plate parallel to the tooth inside the mouth, bite down on it to hold in position, align tube to the outer circle and then the plate and the tube will be parallel
what is the bisecting angle technique?
no film holder is used, the beam is positioned at 90 degrees to bisect the line halfway between the tooth and the film, film held in mouth by patient - difficult to judge, only used where there are difficulties with the paralleling technique
what are the advantages of the bisecting angle technique? - 4 points
can be used in all parts of the mouth
gives a reasonable result
patient comfort
oral anatomy
what are the disadvantages of the bisecting angle technique? - 6 points
prone to inaccuracy incorrect angulation coning off magnification higher skin dose superimposition of zygoma
what 5 things could go wrong with a peri-apical exam?
image elongated - angle too low image foreshortened - angle too high image coned off - not centrally positioned film bending errors with bisecting angle technique
what are the advantages of the paralleling technique? - 4 points
accurate
minimal distortion
sharper image definition
reduces surface dose
what are the disadvantages of the paralleling technique ? - 4 points
holder may be uncomfortable or difficult to position
shallow palate
strong gag reflex
oral anatomy
what does a peri-apical image show? - 4 points
infection around the root
severe periodontal disease
caries (decay)
pathology - e.g. cysts
image evaluation for peri-apicals - 6 points
no evidence of bending of the teeth in peri-apical region
no foreshortening or elongation of the tooth
no horizontal overlap - or if present, not overlap pulp/root canals
image should demo all tooth/teeth of interest (crown and root)
3mm of peri-apical bone visible to allow assessment of apical anatomy
good density and adequate contrast between the enamel and the dentine
why are bite-wings taken? - 2 points
usually on a regular basis (6 months-2 years) to image crowns of teeth to look for caries
show the top of the alveolar bone to allow some assessment of periodontal disease
how are bite-wings taken?
usually uses a tab attached to the plate (bitewing), film holders should now be used - care should be taken to position accurately
