COA COA Radiography & Diagnostic Imaging 2 — Questions and Answers
Question 1: Where is the cephalometric landmark Sella (S) located?
- At the junction of the nasal and frontal bones
- At the tip of the anterior nasal spine
- At the geometric center of the sella turcica (Correct answer)
- At the most inferior point of the orbit
Correct answer: At the geometric center of the sella turcica
Sella is the midpoint of the sella turcica, a saddle-shaped depression in the sphenoid bone housing the pituitary gland.
Question 2: What does the ANB angle indicate in orthodontic diagnosis?
- The inclination of upper incisors to the maxillary plane
- The sagittal (Class I/II/III) relationship between the maxilla and mandible (Correct answer)
- The degree of vertical facial growth
- The dental midline deviation
Correct answer: The sagittal (Class I/II/III) relationship between the maxilla and mandible
The ANB angle (the difference between SNA and SNB) reveals the anteroposterior skeletal relationship between the maxilla and mandible, indicating skeletal Class I, II, or III patterns.
Question 3: What is the primary purpose of periapical radiographs in orthodontic records?
- To measure the total facial height
- To assess root length, morphology, and monitor for root resorption (Correct answer)
- To evaluate jaw symmetry
- To detect maxillary sinus pathology
Correct answer: To assess root length, morphology, and monitor for root resorption
Periapical radiographs reveal the entire tooth including the root apex, allowing orthodontists to monitor root length and detect iatrogenic root resorption.
Question 4: Which radiation safety principle guides minimizing patient X-ray exposure to the lowest dose that still achieves diagnostic quality?
- ALARA principle (Correct answer)
- HIPAA principle
- OSHA radiation standard
- Inverse square law
Correct answer: ALARA principle
The ALARA principle (As Low As Reasonably Achievable) is the guiding standard in dental radiography to minimize unnecessary patient radiation exposure.
Question 5: Where is the cephalometric landmark Nasion (N) located on a lateral cephalometric radiograph?
- At the tip of the nose
- At the most anterior point of the frontonasal suture (Correct answer)
- At the floor of the nasal cavity
- At the posterior nasal spine
Correct answer: At the most anterior point of the frontonasal suture
Nasion is located at the most anterior point of the frontonasal suture, where the nasal and frontal bones join at the bridge of the nose.
Question 6: Which imaging modality provides three-dimensional views of teeth and bone for complex orthodontic cases involving impacted teeth?
- Bitewing radiograph
- Panoramic radiograph
- Cone Beam CT (CBCT) (Correct answer)
- Lateral cephalogram
Correct answer: Cone Beam CT (CBCT)
CBCT (Cone Beam Computed Tomography) generates three-dimensional volumetric images that provide precise localization of impacted teeth and detailed bone assessment.
COA COA Radiography & Diagnostic Imaging 2
Where is the cephalometric landmark Sella (S) located?