Chapters 16,17.18,19,20,21 Flashcards
Type: periapical receptor
Derived from the Greek peri meaning around and the laten word apex referring to the terminal end of a tooth root. Periapical images show the terminal end of the tooth.
Periapical examination : purpose…is used to
Examine the Entire tooth and supporting bone
Technique: Two methods are used for obtaining perapical radiographs.
Paralleling technique and bisecting technique.
Purpose: interproximal examination
Used to examine the crowns of both maxillary and mandibular teeth on a single image. It is useful for examining adjacent teeth surfaces and crestal bone.
Type: bite-wing receptor
Used in interproximal examination. The bite wing has a wing.
Technique:The bite wing technique is used in interproximal examination.
True
Occlusal examination. Purpose:
Used to examine large areas of the maxilla or mandible on one image.
Type: occlusal examination …
Used to examine large areas of the mandibular and maxillary on one image.
Type: occlusal receptor
The patient bites on
Technique for occlusal examination
The occlusal technique
Extra oral radio graphic examination
Radio graphic examination used to examine large area of the skull or jaw.
Extraoral receptors are placed outside of the mouth.
Examples are . The panoramic radiograph, the later jaw , lateral cephalometric, posteroantererior , waters submentovertex, revers town, transcranial, each has a specific purpose.
Parallel
Moving or lying in the same place always separated by the same distance and not intersecting.
Paralleling technique
1 the receptor is placed parallel to the long axis of the tooth being radiographed
2 the central ray of the x ray beam is directed perpendicular to the receptor and the long axis of the tooth .
3 a beam alignment device must be used to keep the receptor parallel to the tooth. The receptor must be placed away from the tooth.
Target receptor
Distance between the source of the X-ray and the receptor must also be increased. A large 16 inch target receptor must be used.
Stabe bit block
One time use (disposable)
XCP instruments, precision film holder, EEZEE-grip film holder, hemostate with bite- block
Must be sterilized after each use.
Receptors used for paralleling technique
Size 1: anterior region , for placement high in the pallet with out bending. Alway positioned vertical. Up right.
Size 2 : posterior : placed long ( side ways)
With a size one receptor a total of ? Anterior placements may be used in the paralleling technique
? Maxillary exposures
? Mandibular exposures
7 total
4 maxillary
3 mandibular
If size 2 receptors are used instead ? Anterior placements are used.
? Maxillary exposures
? Mandibular exposures
6 total
3 maxillary
3 mandibular
Size one is recommended for the
Anterior periapical exposure sequence for the ring XCP Beam alignment instrument.
? Posterior placements may be used for the paralleling technique
? Mandibular
? Maxillary
The exsposure sequence varies depending on the ?
8 posterior placements
4 maxillary
4 mandibular
Sequence varies depending on the Beam alignment
Exposure of maxillary incisor
The mesial contact of the adjacent central incisor and the mesial contact of the adjacent canine should be seen in the exsposure.
Exposure of the mandibular incisor
Entire roots of the four mandibular incisors, including the apices of the teeth and surrounding structures, must be seen in this image .
For maxillary torus
The receptor must be placed on the far side of the torus.
Receptor placement for mandibular premolar region
Receptor must be placed under the tongue.
Beam alignment in the mouth
The receptor is tipped away from th tongue and toward the teeth.
Advantages of the paralleling technique is
That it produces a radiographic image with out dimensional distortion
The bisecting technique
Also known as the bisecting angle technique it is another method for the peri apical images.
Rule of isometry
Two triangles are equal if they have two equal angles and share a common side.
Bisecting technique can be described as follows
1 The receptor must be placed along the lingual surface of the tooth.
2 the dental radiographer must then direct the central ray of the X-ray beam perpendicular to the imaginary bisector. When the central ray is directed at a 90degree angle to the imaginary bisector , two imaginary equal triangles are formed.
Rinn BAI instruments ( bisecting angle instruments)
Bite blocks, plastic aiming rings, and medal indicator arms.
? Can be added to the plastic aiming ring to reduce the amount of radiation received by the patient.
Snap on ring collimators.
Stabe bite block ( Rinn)
Can be used with the parelleling tecnigue or the bisecting tecnigue.
When the Rinn bite block is used with the bisecting technique
The scored front section is removed and the receptor is placed as lose to the teeth as possible.
EEZEE-grip receptor holder ( Rinn) formally known as snap a ray.
Used to stabilize a receptor in either the paralleling technique or bisecting technique
Receptors used in the bisecting technique
Traditionaly a size 2
Horizontal angulation
Referes to the pid and the direction of the central ray in a horizontal or side to side plane.
Vertical angulation
The pid in a vertical up and down plane.
Vertical angular ion is measured in
Degrees and is registered on the out side of the tube head.
Vertical angulation idiffers according to the imaging technique used, as follows : with
1 The bisecting technique
2 The bite wing technique
BISECTING TECHNIQUE : The vertical angulation is determined by the Imaginary bisector. The central ray is directed perpendicular to the imaginary bisector.
BITE WING TECHNIQUE: the vertical angulation is predetermined
The central ray is directed at +40 degrees to the occlusal plan.
Foreshortening of images
Excessive vertical angulation. Also occurs if the central ray is directed perpendicular the plane of the receptor rather than to the imaginary bisector.
Recommended vertical angulation for the bisecting technique
Premolars : maxillary +30 to + 40 Mandibular -10 to -15
Molars : + 20 to + 30. Mandibular -5 to 0
Elongated images referees to images that are too long.
Results from insufficient vertical angulation.
Receptor position for bisecting technique
Must be placed against the lingual surface of tooth with one eighth of an inch beyond the incisal or occlusal surfaces.
Anterior sequence for bisecting technique
Size 2 with a total of 6 anterior placements. Begin maxillary right canine 6
Posterior exposure sequence
Begin with the maxillary right quadrant.
Exposure of maxillary canine
Entire crown and root, the interproximal alveolar bone and mescal contact of the canine must be visible.
Exposure of maxillary incisor
Entire crown and roots of all four maxillary incisors including the apices of the teeth and surrounding structures must be seen.
Exposure of maxillary premolar
All crowns and roots of the first and second premolars and first molar, including apices alveolar crests, contact areas and surrounding bone must be seen.
Exposure of maxillary molar.
All crowns and roots of the first, second, and third molars, including, apices , alveolar crest, contact areas, surrounding bone, and tuberosity region must be seen. Pulse the distal contact of the maxillary second premolar also must be seen.
Advantages of bisecting technique
Primary advantage is it can be used without a beam alignment device. Another advantage is decreased exposure time.
Disadvantages of bisecting technique
Dimensional distortion.
Step one for maxillary premolar exposure using the bisecting technique
Center receptor on the maxillary second premolar, align the front edge of the receptor with the midline of the maxillary canine.
Bite wing tab is an alternative to
a beam alignment device, it can be fitted on a bite wing tab. Also called a bite loop or bite tab.
Bite wing tab
A heavy paperboard tab or loop that is fitted around the intraoral
Receptor and is used to stabilize the receptor.
Available sizes of bite wing devices
0, 2, 3
Size 0 of bite wing receptors are used for
The posterior teeth of children with primary dentitions.
When a bite wing tab is used a vertical angulation of
+ 10 degrees is recommended
In the patient that requires both periapical and bite wing exposures the following exposure sequence is recommended
1 expose all anterior periapical receptors
2 follow with posterior periapical receptors.
3 finish with he bite wing exposures
Molar bite wing exposure with bite tab procedure.
Fold tab in half,crease it. Place lower half of the receptor between the patients tongue and teeth. Place the biting surface of the tab on the occlusal surfaces of the mandibular teeth, center the receptor on the mandibular second molar , the front edge of the receptor should be aligned with he midline of the mandibular second premolar.
To examine the alveolar bone in the mouth a ? Can be used
Vertical bite wing image. It is placed with the Long portion up and down.
Vertical bite wing images are often used as
Post treatment or follow up images for patients with bone loss due to periodontal disease.
With edentulouse or space were teeth are no longer present you can use a
Cotton roll
Exsposure problems: unexposed receptor
Appearance : appears clear
Cause: failure to turn on X-ray machine, electrical failure, malfunction of the X-ray machine.
Film exposed to light
Appearance: image appears black
Underexposed receptor
Appearance : appears light
Cause: was under exposed to radiation.
Correction: check the exposure time,kilovoltage, milliamprage, and increase them as needed.
Underexposed image results from
Inadequate exposure time, kilovoltage
, milliamprage , or combination of these
Absence of apical structure
Appearance: no apices are seen
Correction: make sure that no more than one eight of an inch of the receptor extends beyond the incisal occlusal surface of the teeth
Dropped receptor corner
Appearance : the occlusal plane appears tilted or tipped
Correction: make sure that the receptor is placed parallel to the incisal - occlusal surface of the teeth as the patient bites.
Incorrect horizontal angulation
Appearance : overlapped contacts
Correction: direct the angular ion of he X-ray beam through the interproximal regions.
Incorrect vertical angulation
Appearance: teeth appear short with blunted roots on the image
Cause: the vertical angular ion was excessive ( too steep)
Elongated images
Appearance : teeth appear long and distorted
Cause: the vertical angular ion was insufficient ( too flat)
Cone cut with beam alignment device.
Appearance: clear unexposed area on the image
Cause: the pid was not properly aligned with the peri apical beam alignment device, the X-ray beam did not expose the I tire receptor
To insure the correct placement of the molar bite wing
The receptor must be positioned with he front edge aligned with the midline of the mandibular second premolar
Film bending
Appearance: images appear stretched to distorted
Cause: film bent because of the curvature of the patients hard pallet
Correction: check film placement before exsposure. Coot on tools can be used with the paralleling technique , or the bisecting
Film creasing
Appearance: thin line is seen on the image.
Phalangioma
Patients finger is seen
Make sure the patients finger is placed behind the receptor.
Double exposure
Receptor was exposed twice
Always separated exposed and unexposed receptors
Movement
Blurred images
Either the tube head or the patient moved
Reversed film
Light images with herringbone patterns
Film was placed in the mouth backwards or reversed
The occlusal technique is used to
Examine large areas of the maxilla or mandibible
Occlusal receptor
Size 4 in adults size 2 in children
Three maxillary occlusal projections commonly used.
1 topographic 2 lateral. ( right or left ) 3 pediatric
Maxillary topical projection
To examine the pallet and he anterior teeth of the maxilla
Lateral ( right or left ) projection
Used to examine the palatal roots of molar teeth
Vertical degrees for occlusal protections
Maxillary topographic + 65
Maxillary pediatric. + 60
Buccal object rule ( slob)
S L O B
Same = lingual
Opposite= buccal
Maxillary pediatric occlusal projection
Pid is directed at a + 60 vertical angulation , the top edge of the pid is placed between the eyebrow and center of the nose.
