Transcript الشريحة 1 - muhadharaty.com

Occlusal Radiography: used to examine large areas of maxilla or
mandible on one film size 4( intraoral film) ,the film is named because
the patient occlude or bites on the entire film .
Uses of Occlusal Radiography:
1-To locate retained roots of extracted teeth.
2- To locate supernumerary,unerupted or impacted teeth.
3-To locate foreign bodies in the maxilla or mandible.
4- To locate salivary stone in duct of submandibular gland.
5-To locate and evaluate the extent of lesion e.g,cyst ,tumors in maxilla
or mandible.
6-To evaluate the boundaries of maxillary sinus.
7-To evaluate fracture of maxilla or mandible.
8-To aid in examination of patients who can not open their mouth more
than few millimeters.
9- To examine the area of cleft palate.
10.To measure changes in size and shape of maxilla or mandible.
.
Principles:
The basic principle of the occlusal technique can be described as
follows:
The film is positioned with white side facing the arch that is being
exposed.
The film is placed in mouth between the occlusal surfaces of
maxillary and mandibular teeth.
The film is stabilized when the patient gently bites on the surface of
the film.
.
Anterior Maxillary Occlusal Projection
Image field.
The primary field of this projection includes
the anterior maxilla and its dentition, as well as the anterior
floor of the nasal fossa and teeth from canine to canine.
Film placement.
Adjust the patient's head so that the sagittal plane is
perpendicular and the occlusal plane is horizontal to the
floor.
Projection of central ray.
Orient the central ray through the tip of the nose toward the
middle of the film with approximately +45 degrees vertical
angulation and 0 degrees horizontal angulation.
Cross-Sectional Maxillary Occlusal Projection
Or Upper standard occlusal
I mage field.
This projection shows the palate, zygomatic processes of the maxilla,
anteroinferior aspects of each antrum, nasolacrimal canals, teeth from second
molar to second molar, and nasal septum.
Film placement.
Seat the patient upright with the sagittal plane perpendicular to the floor and
the occlusal plane horizontal.
Projection of central ray.
Direct the central ray at a vertical angulation of +65 degrees and a horizontal
angulation of 0 degrees, to the bridge of the nose just below the
nasion, toward the middle of the film.
Main clinical indications:
The main clinical indications include:
• Periapical assessment of the upper anterior teeth, especially in
children but also in adults unable to tolerate periapical films
• Detecting the presence of unerupted canines, supernumeraries
and odontomes.
• As the midline view, when using the parallax method for
determining the bucco/palatal position of unerupted canines.
• Evaluation of the size and extent of lesions such as cysts or
tumours in the anterior maxilla.
• Assessment of fractures of the anterior teeth and alveolar bone.
It is especially useful in children following trauma because film
placement is straightforward.
Lateral Maxillary Occlusal Projection
or upper oblique occlusal
Image field.
This projection shows a quadrant of the alveolar ridge of the maxilla,
inferolateral aspect of the antrum, tuberosity, and teeth from the lateral incisor
to the contralateral third molar. In addition, the zygomatic process of the maxilla
superimposes over the roots of the molar teeth.
Projection of central ray.
Orient the central ray with a vertical angulation of +60 degrees, to a point 2 cm
below the lateral canthus of the eye, directed toward the center of the film.
Point of entry.
The central ray enters at a point approximately 2 cm below the lateral canthus
of the eye.
Main clinical indications:
• Periapical assessment of the upper posterior teeth, especially in
adults unable to tolerate periapical films.
• Evaluation of the size and extent of lesions such as cysts,
tumours affecting the posterior maxilla.
• Assessment of the condition of the antral floor.
• As an aid to determining the position of roots displaced
inadvertently into the antrum during attempted extraction of upper
posterior teeth.
• Assessment of fractures of the posterior teeth and associated
alveolar bone including the tuberosity.
Anterior Mandibular Occlusal Projection
I mage field.
This projection includes the anterior portion of the mandible, dentition from
canine to canine, and inferior cortical border of the mandible.
Film placement.
Seat the patient tilted back so that the occlusal plane is 45 degrees above
horizontal. Place the film in the mouth with the long axis perpendicular to
sagittal plane and push it posteriorly until it touches the rami, center
the
the film with the tube side down and ask the patient to bite lightly to hold the
film in position.
Projection of central ray.
Orient the central ray with -10 degrees angulation through the point of the
chin toward the middle of the film; this gives the ray -55 degrees of
angulation to the plane of the film.
Point of entry.
The point of entry of the central ray is in the midline and through the tip
of the chin.
Lower Midline Oblique Occlusal Topographic Or
Lower 45°Occlusal
Centering point : symphysis menti
Direction of beam : in the midline , 45° to
the plane of the film.
T-F. distance : 20 cm.
Main clinical indications
• Periapical assessment of the lower incisor teeth, especially
useful in adults and children unable to tolerate periapical films.
• Evaluation of the size and extent of lesions such as cysts or
tumours affecting the anterior part of the mandible.
• Assessment of displacement fractures of the
anterior mandible in the vertical plane.
Cross-Sectional Mandibular Occlusal Projection
Image field.
This projection includes the soft tissue of the floor of the mouth and reveals the lingual
and buccal plates of the mandible from second molar to second molar.
When this view is made to examine the floor of the mouth (e.g., for sialoliths), the
exposure time should be reduced to one half the time used to create an image of
the mandible.
Film placement.
Seat the patient with the head tilted back so that the ala-tragus line is almost
perpendicular to the floor. Place the film in the mouth with its long axis perpendicular to
the sagittal plane and with the tube side toward the mandible. The anterior border of the
film should be approximately 1 cm beyond the mandibular central incisors. Ask the
patient to bite gently on the film to hold it in position.
Projection of central ray.
Direct the central ray at the midline through the floor of the mouth approximately 3
cm below the chin, at right angles to the center of the film.
Point of entry.
The point of entry of the central ray is in the midline through the floor of
the mouth.
Cross-Sectional Mandibular Occlusal
Projection
Or Lower 90° occlusal projection
Main clinical indications:
• Detection of the presence and position of radiopaque calculi in
the submandibular salivary ducts .
• Assessment of the bucco-lingual position of unerupted
mandibular teeth.
• Evaluation of the bucco-lingual expansion of the body of the
mandible by cysts, tumours.
• Assessment of displacement fractures of the anterior body of the
mandible in the horizontal plane.
Anterior True Lower Occlusal View
Centering point :
symphesis menti .
Direction of the beam :
100-110° to the film .
T-F. distance : 30 cm.
Lateral Mandibular Occlusal Projection
Image field.
This projection covers the soft tissue of half the floor of the mouth, the buccal and lingual
cortical plates of half of the mandible, and the teeth from the lateral incisor to the
contralateral third molar. When this view is used to provide an image of the floor of the
mouth, the exposure time should be reduced to one half that used to provide an image
of the mandible.
Film placement.
Seat the patient so that the alatragus line is almost perpendicular to the floor. Place the
film in the mouth with its long axis initially parallel with the sagittal plane and with the
tube side down toward the mandible. Place the film as far posterior as possible, then
shift the long axis buccally (right or left) so that the lateral border of the film is parallel
with the buccal surfaces of the posterior teeth and extends laterally approximately 1 cm.
Projection of central ray.
Direct the central ray perpendicular to the center of the film through a point beneath
the chin, approximately 3 cm posterior to the point of the chin and 3 cm lateral to the
midline.
Point of entry.
The point of entry of the central ray is beneath the chin, approximately 3 cm.
Lower Occlusal for Unerupted Third Molar & Submandibular
Gland
Centering point : angle of mandible, or Submandibular gland
Direction of beam : 110-115° to the film & parallel to the ascending
ramus.
T-F. distance : 30 cm.