Occlusal and Skull Radiography Flashcards
• Display a relatively large segment of a dental arch
• Indications:
1. Location of supernumerary, unerupted and impacted teeth
2. Location foreign bodies in the jaws and floor of the mouth
3. Identify and determine the full extent of disease in the
jaws, palate and floor of the mouth
4. To monitor intermaxillary suture during palatal expansion.
5. To detect sialoliths (sublingual or submandibular glands)
6. To evaluate the walls of the maxillary sinuses.
7. To aid in the examination of patients with trismus
8. To visualize fractures in the maxilla and mandible.
Occlusal Radiographs
What size plate should be used for occlusal radiograph?
4
• Image field: • Anterior maxilla and its dentition • Teeth from canine to canine • Anterior portion of the floor of the nasal cavity
Anterior max occlusal projection
• Receptor placement:
• Sagittal plane of the patient perpendicular to
the floor
• Occlusal plane parallel to the floor
• Posterior portion on the receptor is touching the
ramus
• The long dimension of the receptor is
perpendicular to the sagittal plane of the patient
• Stabilize the receptor by gently closing the
mouth
ANterior max occlusal projection
Projection of the central ray: • Central ray through the tip of the nose towards the middle of the receptor • Approximately +45 degrees of vertical angulation and 0 degrees of horizontal angulation
Anterior max occlusal projection
Image field: • Palate • Zygomatic process of the maxilla • Part of the maxillary sinuses • Nasolacrimal canals • Teeth from 2nd molar to 2nd molar • Nasal septum
Cross sectional max occlusal projection
Receptor placement:
• Sagittal plane of the patient perpendicular to
the floor
• Occlusal plane parallel to the floor
• Posterior portion on the receptor is touching
the ramus
• The long dimension of the receptor is
perpendicular to the sagittal plane of the
patient
• Stabilize the receptor by gently closing the
mouth
Cross sectional max occlusal projection
Projection of the central ray: • Vertical angulation: +65 degrees • Horizontal angulation: 0 degrees • Directed to the bridge of the nose, just below the nasion towards the middle of the receptor
Cross sectional max occlusal projection
Image field: • A quadrant of the maxilla • Maxillary sinus • Tuberosity • Teeth from lateral incisor to the contralateral 3rd molar • Zygomatic process of the maxilla (superimposed over the root of the molars)
Lateral Max Occlusal Projection
Receptor placement:
• Receptor perpendicular to the patient’s
sagittal plane.
• Push the receptor posteriorly until it touches
the ramus
• Position the lateral border of the receptor
parallel with the buccal surfaces of the
posterior teeth, extending laterally
approximately 1 cm past the buccal cusps.
• Close the mouth gently
Lateral Max Occlusal Projection
Projection of the central ray: • Vertical angulation: +60 degrees • Orient the central ray to a point 2 cm below the lateral canthus of the eye, directed towards the center of the receptor
Lateral Max Occlusal Projection
Image field: • Anterior portion of the mandible • Dentition from #22 to #27 • Inferior border of the mandible
Anterior Mandibular Occlusal Projection
Receptor placement: • Patient is tilted back → the mandibular occlusal plane is 45 degrees from the floor • Push the receptor posteriorly until it touches the ramus • Close the mouth
Anterior Mandibular Occlusal Projection
Projection of the central ray:
• -55 degrees to the receptor
• Place the PID in the midline
and through the tip of the chin
Anterior Mandibular Occlusal Projection
Image Field: • Soft tissue of the floor of the mouth • Lingual and buccal plates of the mandible from 2nd molar to 2nd molar • When this view is made to examine the floor of the mouth (e.g., for sialoliths), the exposure time should be reduced to half
Cross-sectional Mandibular
Occlusal Projection
Projection of Central Ray: • Central ray at the midline through the floor of the mouth • Approximately 3 cm below the chin • Right angle to the center of the receptor
Cross-sectional Mandibular
Occlusal Projection
Receptor Placement: • Patient’s head tilted back so that the ala- tragus line is almost perpendicular to the floor. • Push the receptor posteriorly until it touches the ramus • The anterior border of the receptor should be approximately 1 cm beyond the mandibular central incisors. • Close the mouth
Cross-sectional Mandibular
Occlusal Projection
Image Field: • Soft tissue of half the floor of the mouth • Buccal and lingual cortical plates of half of the mandible • Teeth from the lateral incisor to the contralateral 3rd molar
Lateral Mandibular Occlusal
Projection
Receptor Placement:
• Patient’s head tilted back (ala-tragusline almost perpendicular to the floor)
• Push the receptor posteriorly
• Shift the receptor (right or left) so thatthe lateral border of the receptor isparallel with the buccal surfaces of theposterior teeth and extends laterallyapproximately 1 cm.
• The anterior border of the receptor →
1 cm beyond the mandibular incisors.
• Close the mouth
Lateral Mandibular Occlusal
Projection
Projection of Central Ray: • Central ray perpendicular to the receptor • Approximately 3 cm below the chin
Lateral Mandibular Occlusal
Projection
• X-ray source and receptor are placed outside the patient’s
mouth (both remain static)
• Why?
• To examine areas not fully covered by intraoral radiographs
like the cranium, facial bones and cervical spine
• Limited mouth opening
• Growth assessment
• Determine relationship between facial and dental structures
Dental caries and periodontal disease cannot be evaluated
Skull radiographs
The following are \_\_\_\_\_ radiographs 1. Lateral cephalometric 2. Posteroanterior cephalometric 3. Cadwells 4. Water’s projection 5. Reverse Towne 6. Submentovertex
Skull radiographs
What is the line that is used to correctly position patient taking skull radiographs?
Canthomeatal line
▪ Most commonly used. ▪ Lateral view of skull, teeth and soft tissue. Indications: -Orthodontics (growth and development) -Facial soft-tissue profile -Orthognathic surgery evaluation -Anterior-posterior view of the paranasal sinuses Identify: - Frontal, ethmoidal, maxillary and sphenoid sinuses
- Lateral Cephalometric
Image receptor Parallel to the pt. mid-
sagittal plane.
X- ray beam centered External auditory
meatus
Lateral Cephalometric
Indications: • Evaluation of facial asymmetries. • Assessment of skull fractures. • Assessment of orthognathic surgery outcomes. Identify: • Orbits • Nasal cavity • Frontal sinuses
- Posteroanterior cephalometric
Image receptor In front of the pt. and
perpendicular to the
mid-sagittal plane.
X- ray beam centered Nasal bridge
Posteroanterior cephalometric
• It is an angled posteroanterior
radiograph of the skull
• Used to see the frontal sinuses.
Caldwell view
Image receptor The patient's forehead is placed against the image detector. X- ray beam centered Angled around 15° to nasal bridge CML should be parallel to floor: Beam should be 15-20 degrees above CML
Caldwell view
• Indication: evaluation of the sinuses Image receptor In front of the pt. and perpendicular to the mid-sagittal plane. X- ray beam is centered Maxillary sinus. Head tilted upwards 37 degree angulation of CML from beam
Water’s projection
Indications: Assessment of the condylar area: • Fracture. • Hypoplasia/hyperplasia Image receptor In front of the pt. and perpendicular to the mid-sagittal plane. X- ray beam is centered At condylar level . Open mouth CML at -30 degree angle compared to beam
Reverse Towne’s view
Indications: • Evaluation of the sphenoid sinuses. • Lesions of the palate • Evaluate fracture of the zygomatic arch (underexposed image) Image receptor Parallel to the patient’s transverse plane. X- ray beam is centered Below the mandible and toward the vertex of the skull. CML parallel to floor
Submentovertex
To see a zygomatic arch fracture, should you under or overexpose?
Underexpose
