oral radiology ch 8, 18, and 19 quiz

Why do we take periapical radiographs?

• used to examine the entire tooth and supporting bone, examine “around apical”

• uses __ receptor

• utilized paralleling and bisecting technique*

Why do we take interproximal (BWX’s) radiographs?

• to examine the crowns and contacts of both the maxillary and mandibular teeth on a single film

• used for interproximal examination, therefore no overlapping can occur

• uses bite-wing receptor

• uses bite-wing technique

What is covered on a FMX?:

• also known as CMS or FMS

• a full-mouth series or complete series that consists of tooth-bearing areas (dentulous or edentulous areas)

• includes periapical and bitewings

• 14 to 20 films may be taken

What makes a x-ray image diagnostic?

• must show the entire crowns and roots of teeth being examined, as well as 2 to 3 mm beyond root apices

• BWX images must show open contacts, optimum density, contrast, definition, and detail with the least amount of distortion possible

What are the basic principles of paralleling?:

• receptor is placed in the mouth parallel to long axis of tooth

• central ray of x-ray beam is directed perpendicular to the film and the long axis of the tooth

• beam alignment device must be used to keep the receptor parallel with the long axis of tooth

  • recePtor → Parallel

  • Central Ray → perpendiCulaR to sensor and tooth

How do we achieve parallelism between the receptor and the tooth

• increase object-receptor distance to insure receptor is parallel with long axis of tooth

basic rules of paralleling

• Receptor placement: Position the image receptor so that it will cover the correct teeth to be examined

• Receptor position: the image receptor must be positioned parallel to the long axis of the tooth

• Vertical angulation: the central ray of the x-ray beam must be directed perpendicular to the image receptor nd the long axis of the tooth

•   Horizontal angulation: the central ray of the x-ray beam through the contact areas between the teeth

• Film receptor exposure: The X-ray beam must be centered on the receptor to ensure that all areas are exposed. Failure to do so will result in “cone cut.”

Digital image

• an image composed of pixels that can be stored in a computer

• commonly used to detect lesions, disease, and conditions of teeth and supporting structures

• use LESS radiation exposure than film (50-90% less exposure time)

Analog image

produced from conventional film

Bit-depth image

• number of possible gray-scale combinations for each pixel

• 254 shades of gray possible

Digital imaging:

• filmless imaging system

• a method of capturing an image using sensor, breaking it into electronic pieces, and presenting and storing image in computer software

digital subtraction

• one feature of digital imaging

• method of reversing the gray scale as image is viewed

• radiolucent appear white

• radiopaque appear black

direct digital imaging

• a sensor is placed into the mouth of the patient and exposed

• the sensor captures the image and transmits it to the computer monitor

• software is used to enhance and store image

indirect digital imaging

• method of obtaining a digital image

• an exsisting x-ray film is digitized using a CCD camera

• the image is displayed on a computer monitor

line pairs/ millimeter (lp/mm)

• measurement used to evaluate the ability of the computer to capture the resolution (or detail) of an image

pixel

• a discrete unit of information

• picture element

• digital information is contained in, and presented as, discrete units of information

sensor

• a receptor that is used to capture an intraoral or extraoral image

• we will be using a size 2 receptor

storage phosphor imaging

• method of obtaining a digital image in which the image is recorded on a phosphor coated plate and then placed into an electronic processor where a laser scans the plate and produces an image on a computer monitor

charge coupled device (CCD)

• solid state silicone chip detector that converts lights or x-ray photons into an electrical charge or signal

• found in sensor

Rinn XCP-ORA one ring and arm positioning system

• one ring

• one arm

• is a beam alignment device that is used to position receptor in the mouth and retain receptor in position during exposure