Chapter 20: Bisecting Technique Flashcards
Principles, Equipment and Guidelines of the Bisecting Technique
Define the term: anterior
towards the front
What is the primary disadvantage of using the bisecting technique?
dimensional distortion
What is the result of correct vertical angulation when using the bisecting technique?
the image is the same length as the tooth
Define the term: beam alignment device
- a device used to align the position-indicating device in relation to tooth and image receptor
- positions the intraoral image receptor in the mouth and retains the image receptor in position during exposure
- helps stabilize the image receptor in the mouth and reduces the chances of movement, thus reducing the patient’s exposure to x-radiation
Define the term: forshortened image
an image of a tooth that appears short and distorted
Define the term: overlapped contacts
on a dental image, the area where the contact area of one tooth is superimposed over the contact areas of an adjacent tooth
Define the term: intersecting
cutting across or through
Define the term: intraoral imaging examination
a dental imaging inspection of teeth and intraoral adjacent structures
Define the term: vertical angulation
the positioning of the position-indicating device in a vertical plane
Define the term: open contacts
on a dental image, appears as a thin radiolucent line between adjacent tooth surfaces
Where is the image receptor placed when using the bisecting technique?
along the lingual surface of the tooth
Define the term: triangle
- in geometry, a figure formed by connecting three points not in a straight line by three straight-line segments
- has three angles
Once the image receptor is placed, how must the central ray be positioned against the imaginary bisector when using the bisecting technique?
the central ray must be perpendicular to the imaginary bisector
Define the term: bisect
to divide into two equal parts
Define the term: Rinn XCP instrument
- a type of beam alignment device that is used with the paralleling technique
- includes plastic bite blocks, plastic aiming rings, and metal indicator arms
Define the term: isometry
equality of measurement
Define the term: periapical examination
a type of intraoral imaging examination used to view the entire tooth (crown and root) and supporting bone
Define the term: horizontal
a side-to-side plane
Define the term: equilateral triangle
in geometry, a triangle with three equal sides
Define the term: congruent triangles
in geometry, triangles that are identical and correspond exactly when superimposed
Define the term: object-receptor distance
- the distance from the object being imaged (tooth) to the image receptor influences image magnification
- less image magnification results when the tooth and the image receptor are as close as possible, and more magnification results when the tooth and receptor are far apart
Define the term: forshortening
- a term describing the image of a tooth that appears shorter than the actual tooth
- results from steep or excessive vertical angulation
Define the term: contact areas
the areas where adjacent tooth surfaces touch each other
How will the contact areas appear as a result of incorrect horizontal angulation in the bisecting technique?
overlapped contacts
What is the correct horizontal angulation in the bisecting technique?
the central ray is directed perpendicular to the dental arch and through the contact areas of the teeth
Define the term: elongation
- a term used in imaging to describe an image of a tooth that appears longer than the actual tooth
- results from flat or insufficient vertical angulation
Define the term: elongated image
an image of a tooth that appears long and distorted
Define the term: bisecting technique
- an intraoral imaging technique used to expose periapical receptors
- the image receptor is placed along the lingual surface of the tooth, the central ray of the x-ray beam is directed perpendicular to the imaginary bisector formed by the image receptor and the long axis of the tooth
- receptor holder is used to stabilize the image receptor
Define the term: parallel
moving or lying in the same plane; always separated by the same distance and not intersecting
Define the term: angle
in geometry, a figure formed by two lines diverging from a common point
Define the term: horizontal angulation
the positioning of the position-indicating device in a horizontal plane
Define the term: Rinn Snap-A-Ray Holder
an intraoral receptor holder used to stabilize an image receptor during exposure
What is the primary advantage of using the bisecting technique?
eliminating the use of a beam alignment device
Define the term: image receptor holder
a device used to hold an intraoral image receptor in the mouth and stabilize the receptor’s position during the exposure
Define the term: periapical image
intraoral image that is used to examine the crowns and roots of teeth
Define the term: image receptor placement
the specific area where the image receptor must be positioned before exposure
Define the term: vertical
an up-and-down plane
Define the term: intraoral
inside the mouth
What images can be taken using the bisecting technique?
periapical images
What geometric principle is the bisecting technique based on?
rule of isometry
Define the term: rule of isometry
a geometric principal that states that “two triangles are equal if they have two equal angles and share a common side”
Define the term: interproximal
between two adjacent surfaces
Define the term: long axis of a tooth
an imaginary line that divides a tooth longitudinally into two equal halves
Define the term: right triangle
in geometry, a triangle with one 90-degree angle
Define the term: exposure sequence
a defined order to place and expose intraoral receptors
Define the term: periapical receptor
an intraoral image receptor used to examine the entire tooth (crown and root) and supporting bone
Define the term: imaginary bisector
- an imaginary plane that divides in half the angle formed by the image receptor and the long axis of the tooth
- creates two equal angles and provides a common side for the two imaginary equal triangles
Define the term: Stabe Biteblock
a disposable styrofoam device that can be used to hold an image receptor during exposure
Define the term: angulation
the alignment of the central x-ray beam in the horizontal and vertical planes
Define the term: image receptor
a recording medium (ex: PSP plate, digital sensor)
How will the contact areas appear as a result of correct horizontal angulation in the bisecting technique?
opened contacts
What is the correct vertical angulation in the bisecting technique?
- vertical angulation is determined by the imaginary bisector
- the central ray is directed perpendicular to the imaginary bisector
What is the result of incorrect vertical angulation when using the bisecting technique?
the image is not the same length as the tooth, and appears distorted or elongated
Define the term: position-indicating device (PID) / cone
- an open-ended, lead-lined cylinder extending from the opening of the tubehead
*aims and shapes the x-ray beam
Define the term: periapical
around the apex of a tooth
Define the term: right angle
in geometry, an angle of 90 degrees formed by two lines perpendicular to each other
Define the term: intraoral image
- an image the results when an image receptor is placed inside the mouth and exposed to x-rays
- used to examine teeth
Define the term: hypotenuse
in geometry, the side of a right triangle opposite the right angle
