LECTURE 4: INTRAORAL RADIOGRAPHY Flashcards
radiographic procedures where the film is placed inside the mouth to make exposure or a radiograph
INTRAORAL RADIOGRAPHY
types of INTRAORAL RADIOGRAPHY
o periapical technique
o bitewing technique
o occlusal technique
PERIAPICAL TECHNIQUE
can be either?
o paralleling technique
o bisecting technique
PARALLELING TECHNIQUE
also known as?
o extension cone technique
o right angle technique
o long cone technique
True or false
film position in the mouth is parallel to the long axis of the tooth to be radiographed
True
True or false
central ray of x-ray beam is directed parallel to film and long axis of the tooth
False
central ray of x-ray beam is directed perpendicular to film and long axis of the tooth
True or false
keep the film parallel with the long axis of the tooth
True
True or false
central beam is perpendicular to the tooth and film; film parallel to the tooth
True
True or false
Paralleling instruments with an aiming ring is doesnt needed to achieve the parallel relationship.
False
Paralleling instruments with an aiming ring is needed to achieve the parallel relationship.
LONG TARGET FILM DISTANCE
INCHES?
16 INCHES
used with paralleling technique to compensate for the image magnification
LONG TARGET FILM DISTANCE
reason why this technique is also referred to as long cone technique
LONG TARGET FILM DISTANCE
long target-film distance produces image with less image magnification and increased definition
LONG TARGET FILM DISTANCE
reason why cone is 16 inches long
LONG TARGET FILM DISTANCE
PARALLELING TECHNIQUE
LONG TARGET FILM DISTANCE
ADVANTAGES:
→ produces images with dimensional accuracy
→ simple and easy to learn and use
→ can be accurately repeated (easier to standardize films)
→ head position is not critical
PARALLELING TECHNIQUE
LONG TARGET FILM DISTANCE
DISADVANTAGES:
→ film placements may be difficult
→ film holding device may cause patient discomfort
FIVE BASIC RULES of PARALLELING TECHNIQUE
(1) Film must cover the prescribed area of interest
(2) Film positioned parallel to the long axis of the tooth
(3) Central ray directed through the contact areas between the teeth
(4) X-ray beam centered over the film to ensure all areas of the film are exposed
MODIFICATIONS THAT CAN CAUSE CHALLENGES in using PARALLELING TECHNIQUE
→ low palatal vaults
→ maxillary torus
→ mandibular torus
based on a simple geometric principle known as rule of isometry
BISECTING ANGLE TECHNIQUE
two triangles are equal if they have two equal angles and share a common side
BISECTING ANGLE TECHNIQUE
Cieszynski’s rule of isometry
BISECTING ANGLE TECHNIQUE
in this technique:
o film is placed along the lingual surface of the tooth
BISECTING ANGLE TECHNIQUE
at point where film contacts tooth, plane of film and long
axis of tooth form an angle
BISECTING ANGLE TECHNIQUE
o an imaginary bisector divides the angle in half or bisects it
BISECTING ANGLE TECHNIQUE
central ray of x-ray beam is directed perpendicular to the
imaginary bisector
BISECTING ANGLE TECHNIQUE
the radiographer must visualize an imaginary plane that bisects
or divides in half that angle formed by the tooth and the film
BISECTING ANGLE TECHNIQUE
opposite hands for each side (both maxillary and mandibular)
FINGER STABILIZATION TECHNIQUE
thumb for the upper teeth
FINGER STABILIZATION TECHNIQUE
pointer finger for lower teeth
FINGER STABILIZATION TECHNIQUE
True or false
In FINGER STABILIZATION TECHNIQUE,
to prevent excess bending of the film at the root apex you should apply heavy pressure at the junction of the tooth crown and gum line
False
to prevent excess bending of the film at the root apex you should apply light pressure at the junction of the tooth crown and gum line
RECOMMENDED VERTICAL ANGULATION in Maxillary:
Incisors
Canines
Premolars
Molars
Incisors +60
Canines+50
Premolars+40
Molars+30
RECOMMENDED VERTICAL ANGULATION in Mandibular
Incisors
Incisors
-15 to -25
RECOMMENDED VERTICAL ANGULATION in Mandibular
Canine
-20 to -30
RECOMMENDED VERTICAL ANGULATION in Mandibular
Premolars
-10 to -15
RECOMMENDED VERTICAL ANGULATION in Mandibular
Molars
-5 to 0
BISECTING ANGLE TECHNIQUE
ADVANTAGES
→ can be used without a film holder
→ decrease exposure time
BISECTING ANGLE TECHNIQUE
DISADVANTAGES
→ image distortion
→ angulation problems
