1periapical radiography
emphasis on apex and area around
looks at anatomy, lesions, or abcess at PA area
crown, root, 2-3mm PA area
2bitewing radiography
interproximal caries
2ndary caries under resto
alv crest height, bone loss, calculus
3full mouth series
16 PA
4 BW (only PMs and M), all interprox contact should be OPEN
4in FMS, for periodontal eval, which BW is preferred
vertical-if bone loss is significant
5types of image receptors in xray
films
PSP
sensors (require least modification/additions)
6sensor holding device: color coded
yellow - posterior PA
blue - anterior PA
red - BW
7what sensor system do we use at VCU?
XCP-ORA, one ring one arm
one white ring has all 3 colors, just change arm and bar positioning
8bite blocks (snap-a-ray) are for
pts with gag or big torii
9what shape is PID and why
rectangular, reduces radiation by 75%
10what should the pt position be during xray
occlusal plane is parallel to the floor
11exposure time ant vs post
posterior exposure time HIGHER, xray needs to travel through more tissue or bone
12sensor sizes
size 1: smaller, for anterior PA
size 2: bigger, for posterior PA/BW
13projection geometry
effects of focal spot size, position of obj, and film/sensor on image clarity, magnification, and distortion
14image sharpness
how well a boundary b/t two areas of diff radiodensity is shown
need good img sharpness for incipient caries, picking up subtle differences
15spatial resolution
how well an xray can reveal small objects that are close together
if you can tell apart enamel, dentin, lamina etc there is good spacial res
16factors affecting img sharpness and resolution
focal spot size
dist b/t image receptor and object
dist b/t focal spot and object
17if focal spot is smaller
higher resolution
18for a sharper image, the distance between focal spot and object must be
LONGER (why we use PID)
19for a sharper image, the dist bt image receptor and object is
smaller dist
mnemo: receptors are small so small dit b/t receptor-tooth
20image shape distortion
when an object looks shorter(foreshortened) or elongated
21techniques for PA
paralleling (most common)
bisecting
22parallel tech for PA
long axis of tooth and sensor are PARALLEL
xray beams are PERPENDICULAR to them
23bisecting angle tech for PA
sensor right against tooth
imaginary line bisecting the sensor and long axis
xray beam PERP to imaginary
24how should sensor be placed when taking xrays
parallel to buccal surfaces of capture area
25paralleling technique advantages
Simplicity
Accuracy
Duplication
26|| tech disadv
film placement
discomfort
27tip for placing sensor w maxillary centrals
push sensor to middle of hard palate (@lvl of 2PM); more height, avoids missing PA lesion
28max central PA should incl
both central incisors, their PA areas, open ipc, and 3mm PA bone
29why do we need to include distal 3rd of canines in BW
in canine PA, there will always be overlap bt k9 and PM
30what error happens if sensor is not in the center of the ring
cone cut
31where to center sensor for max PM PA
center over 2PM or as anterior as possible
(this is to include the distal half of canine)
32max premolar PA shoiuld include
both PM, distal 3rd canine, first molar
33where to center sensor for max molar
2M, or distally as possible without gag reflex
close to midline of palate to capture complete tooth from crown to root
34max molar PA should include
all 3 molars and part of tuberosity
35where to center sensor for mandibular incs and what size
size 1
lingual sulcus, move pt tongue
36mand PM PA should include
distal 3rd of canine, PMs, 1M
37accentable vertical angulation for bw
positive ang of +7 to +10
38most common xray errors
interprox overlap
cone cut