intraoral imaging Flashcards
Size (0) receptor
used for children
Size (1) receptor
used for children and adult anteriors
Size (2) receptor
used for adult bitewings and periapicals. Also used for children’s occlusal images
Size (3) receptor
longer version of the bitewing, only one image is taken on each side.
Size (4) receptor
used for occlusal techniques
Periapical (PA)
captures the crown, CEJ, root, and surrounding areas
Used mainly for diagnosis of periodontal disease, pathology, endodontic therapy, and implants
Bitewing (BWX)
captures the crown, contact, and height of alveolar bone of posterior teeth
- Used mainly for diagnosis of dental caries (only interproximal)
- Vertical bitewings can detect early periodontal disease if the bone level is visible
- The occlusal plane should be parallel to the floor. The x-ray tube should have a +10 degree vertical angulation
- The premolar bitewing image should include the distal half of the canines, both premolars, and the first molar
- The molar view should be centered over the second molar
Occlusal
captures remnants of roots (extracted), supernumerary teeth, impacted teeth, fractures, clefting, bone surrounding the teeth, floor of the mouth, sialolith (stone), and shape of the arch of a larger area
- Patient gently bites on the receptor with the maxillary and mandibular teeth
- Useful when patient has limited jaw opening
- # 4 receptor is used for adults while #2 receptor is used for children
Full-mouth series (FMX)
represent the entire dentition using a combination of PAs and BWs
usually 16-20 images (12 PAs and 4-6 BWX); varies by patient
Bitewings are not needed for what?
Edentulous dentition
loss of all dentition
Bisecting technique
based on the rule of isometry (two triangles are equal when they share one complete side and have two equal angles)
- The primary beam hits at a 90° angle to the bisected line
Bisecting Line
created by film and long axis of the tooth
bisecting technique
where is the receptor placed?
directly against the teeth to be exposed and this creates an angle between the receptor and long axis of the tooth
Draw an imaginary bisecting line of this angle
does the bisecting techique produce more distortion than the paralleling technique?
yes, because of the position of the palate and the difficulty of visualizing the bisecting line
the bisecting technique is an alternative to a paralleling technique for patients with a small mouth, tori, or shallow palate
Angulations
canines
+45 to +55 (maxillary), -20 to -30 (mandibular
Angulations
incisors
+40 to +50 (maxillary), -15 to -25 (mandibular)
Angulations
premolars
+30 to +40 (maxillary), -10 to -15 (mandibular)
Angulations
molars
+20 to +30 (maxillary), -5 to 0 (mandibular)
Paralleling technique
(long-cone, right-angle technique)
the receptor is parallel to the long axis of the tooth
T/F
the paralleling technique provides more accurate image with less distortion than bisecting technique
True
how is the receptor positioned when using a paralleling technique?
the receptor is positioned farther from the tooth surface, which therefore creates magnification, but this can be compensated by an increased tube-to-tooth distance
Paralleling technique
at what angle should the primary beam hit the receptor and at what axis of the tooth?
90 degree angle, long axis
Paralleling technique
where are the x-ray beams directed through?
the contact areas (between teeth)
who is the paralleling technique not feasible for?
patients with a shallow palate, tori, or small mouth
occlusal techniques
Mandibular occlusal technique
head tilted backward, negative 55° vertical angulation
Central rays are directed through the chin
occlusal techniques
Maxillary occlusal technique
occlusal plane parallel to the floor, positive 65° vertical angulation
Central rays are directed through the tip of the nose
occlusal techniques
Cross-sectional maxillary occlusal technique
occlusal plane parallel to the floor
Beams are perpendicular to the receptor & directed between the *eyebrows
occlusal techniques
Cross-sectional mandibular occlusal technique
head tilted backward until the ala-tragus (“ala” meaning side of the nose, “tragus” meaning flap of the ear) line is almost perpendicular to the floor
Beams are perpendicular to the receptor & directed *inferior to the chin
buccal object rule
slob: same lingual, opposite buccal
Shows whether an artifact is lingual or buccal. A radiograph is a two-dimensional image of a three-dimensional space. Therefore, a bitewing or PA only shows the anteroposterior location of the artifact
Two images needed, whether they are PA or BWX. The second image is taken from a different horizontal or vertical angulation
slob
why should the two images be compared?
to see if the artifact moves towards the same or opposite direction compared to the change in the tube head position
object is located lingually if?
Tube head and object moved in the same direction
object is located bucally if?
Tube head and object moved in the opposite direction
Patient Positioning
- Patient must sit upright
- Adjust the headrest to support the patient’s head
- Secure the lead apron and thyroid collar
- For bitewings, the occlusal plane should be parallel to the floor
- Maxillary arch exposure: head is upright
- Mandibular arch exposure: head is tipped back slightly
- Angulation positioning device can help align the x-ray beams to the receptor. If a bitewing tab is used, the clinician needs to determine the horizontal and vertical angulation.
Assembly
- Assemble the receptor holding kit with clean gloved hands
- Allow the patient to observe the process to demonstrate proper infection control measures
- With digital sensor, use a plastic barrier to cover the sensor
technique errors
Overlap
inappropriate horizontal angulation → direct beams through contacts
technique errors
Foreshortening
too much vertical angulation → decrease angulation
technique errors
Elongation
too little vertical angulation → increase angulation.
technique errors
Circular white border
cone cut → PID should cover the entire surface of the film
Amalgam
completely radiopaque
Gold
completely radiopaque, even in crown, inlay, and onlay
Retention Pins
radiopaque, used to stabilize the radiograph
Base material
slightly radiopaque, used to protect the pulp
Gutta-perch
slightly radiopaque, substance that fills tooth canals
Silver point
radiopaque, used to obliterate canals during endodontic therapy
Composite
radiopaque, the density of opacity varies with the composition of the material
Porcelain
slightly radiopaque
Orthodontics
radiopaque
Implants
radiopaque, resembles a screw
PFM
porcelain fused to metal
radiopaque, the underlying layer is metal
Which anatomical landmark can potentially be seen with periapicals of the maxillary central incisors?
median palatine suture
the union of the two horizontal palatal plates and appears as a thin radiolucent line between the maxillary central incisors
Panoramic imaging
useful for assessing trauma or development of the jaw, but they may not provide enough clarity for detecting signs related to periodontal diseases or carious lesions
Failing to have the x-ray beam in a position that’s perpendicular to the receptor in a paralleling technique will result in?
foreshortening and elongation
