DENT 1050 Test Study; ch. 30, 31, 32, 33, 35 & lab ch. 18 Flashcards Preview

Dental Radiography > DENT 1050 Test Study; ch. 30, 31, 32, 33, 35 & lab ch. 18 > Flashcards

Flashcards in DENT 1050 Test Study; ch. 30, 31, 32, 33, 35 & lab ch. 18 Deck (33):

Bisecting Technique

Film Placement: Selected teeth;
Film Position: film is placed against the tooth, the occlusal end of the film should extend at least 1/8 inch beyond the incisal/occlusal surface;
Vertical angulation: central ray is directed perpendicular to the imaginary bisector that divides the angle formed by the film and long axis of the tooth;
Horizontal angulation: Through the contacts


Target to tooth

central ray is directed perpendicular to the imaginary bisector that divides the angle formed by the film and long axis of the tooth;



Results from insufficient vertical angulation



stabe blocks or snap a rays


Bite blocks

Stabe Bite-block: (used in both the paralleling and bisecting techniques)
The scored front section is removed and the film is placed as close to the teeth as possible


Snap a ray

used in both paralleling and bisecting techniques


Caries definitions

Incipient Interproximal Caries (Class I): extends less than ½- way through the enamel
Moderate Interproximal Caries (Class II): extends more than ½-way through the enamel but does not yet involve the DEJ (or dentin)
Advanced Interproximal Caries (Class III): extends to or through the DEJ and into dentin (but not more than ½-way through the dentin)
Severe Interproximal Caries (Class IV): extends more than half the distance to the pulp (through the dentin)
May appear clinically as a hole (cavitation) in the tooth


Cysts - radiopaque or radiolucent

1. Focal opacity- well defined
a. Condensing osteitis
2. Target lesion- localized opaque, surrounded by radiolucent halo.
a. Benign cementoblastoma
3. Multifocal confluent- multiple radiopacities that appear to overlap or flow together.
a. Osteitis deformans and florid osseous dysplasia
4. Irregular- poorly defined pattern, usually malignant
a. Osteosarcoma and chondrosarcoma
5. Ground glass- granular or pebbled looking bone
a. Fibrous dysplasia, osteitis deformans
6. Mixed lucent-opaque- has mixed radiolucent and radiopaque look.
a. Calcifying tumors – compound odontoma


Dental materials look like what on radiographs?

Metallic restorations (amalgam, gold)
1. Opaque or white area on film

Nonmetallic Resotration
(porcelain, composite, acrylic)
1. Appear radiolucent to slightly opaque



equality of measurement; mirror image; Rule of Isometry: two triangles are equal if they have two equal angles and share a common side



Results from excessive vertical angulation (too steep);
Can result if the central ray is directed perpendicular to the plane of the film rather than the imaginary bisector



used in anterior porcelain denture teeth


Post and Core

endodontic therapy and tooth build-up; are radiopaque


Porcelain crowns

have a thin line of cement around the tooth prep


Gold crowns and bridges

large and smooth; well adapted margins.



small and non-expansile and have borders that may be corticated or non-corticated ( dense or not dense border)



multiple radiolucent compartments and is a larger lesion
a. Well defined coricated margins
b. Frequently expansile-displacement of buccal and linqual plates of bone.


Moth-eaten pattern

ill-defined borders



Metallic restorations, Bone, Enamel, Newer composite restorations, Dentin



a. Caries
b. Air spaces
c. Soft tissue
d. Abscesses
e. Dental pulp
f. Periodontal ligament space


Final interpretation

made by dentist


Interpretation terminology

To offer an explanation
An explanation
Image interpretation:
An explanation of what is viewed on a dental image; the ability to read what is revealed by a dental image.
The identification of a disease by exam or analysis.


interpretation and dental team

Other members of dental team are restricted by law to diagnose.


interpretation of caries

A lower kVp yielding a high contrast and short-scale is best


Caries classes: interproximal

Class I: Incipient interproximal
Class II: Moderate interproximal
Class III: Advanced interproximal
Class IV: Severe interproximal


Caries classes: occlusal

Incipient Occlusal Caries
Moderate Occlusal Caries
Severe Occlusal Caries


Root Fractures:

occur most often in max. central area;
It is critical that the paralleling technique is used otherwise the fracture may be obscured by the surrounding root structure;
It appears as a thin radiolucent line that may widen with time;
Vertical: teeth pulled as the bacteria easily travel down it.



abnormal displacement of teeth, teeth should be evaluated using a PA to view the bone, pulp and PDL involved
a. Intrusion: tooth gets displaced into the bone
b. Extrusion: tooth gets displaced out of bone



the complete displacement of a tooth from the alveolar bone
A radiograph (PA) should be used to view the socket area (splintered bone may be present


External Resorption: seen along the periphery of the root surface

Associated with:
Re-implanted teeth, abnormal mechanical forces, trauma, chronic
inflammation (perio), tumors, cysts, impacted teeth, or is idiopathic
no treatment


Internal Resorption: involves the pulp and dentin of the crown/root

Precipitated by trauma,
pulp capping, pulp polyps;
root canal or extraction


Pulpal lesions

Pulpal Sclerosis:
Calcification of the pulp chamber resulting in decreased size
1. Associated with aging
2. No clinical features or symptoms, only becomes a problem if RC is needed
Pulpal Obliteration:
Complete obliteration of the pulp & replacement w/ 2nd dentin
Non vital tooth and no treatment is needed
Secondary dentin is laid down in response to attrition, caries, restorations, trauma, abnormal mechanical forces, etc.)
Pulp Stones:
Calcifications found w/in the pulp
Cause is unknown
Appears radiographically as rounded radiopacities w/in the pulp (vary in size)
Asymptomatic and do not require treatment


Five basic rules for bisecting technique

1. receptor must cover the prescribed area of interest
2. receptor must be positioned with one eighth of an inch extending beyond incisal or occlusal surfaces
3. central ray must be directed perpendicular to the imaginary bisector that divides the angle formed by the tooth and the receptor
4. central ray must be directed through the contact areas between teeth
5. x-ray beam must be centered over the receptor to ensure that all areas of the receptor are exposed