Module 2: Radiography Lecture

Question 1

What are the three areas of importance related to radiographs in endo?

Answer 1

Diagnosis
Treatment
Recall

Question 2

What are the three primary ways in which Radiographs are used in diagnosis?

Answer 2

Identifying Pathosis
Determining Root and Pulpal Anatomy
Charaterizing normal structures

Question 3

What are radio graphs used for in the treatment phase?

Answer 3

Determining working lengths
Locating Canals
Obturation

Question 4

What are radiographs used for in the recall phase?

Answer 4

Healing of the pathos

Determining other treatment options

Question 5

What is the most common recall duration

Answer 5

1 year

Question 6

What is the primary type of radiograph used in endo?

Answer 6

PA

Question 7

How much bone should be visible beyond the apex of the tooth in an endo PA?

Answer 7

At least 2mm

Question 8

Besides 2mm of bone, what else should be clearly visible in an endo PA?

Answer 8

The entire periapical lesion

Question 9

What is the complete series of endo PA’s for a treament?

Answer 9

Pre-procedure
During Procedure
Post-op
Recall

Question 10

What are the primary limitations of Radiographs?

Answer 10

Two dimensional representation of tooth
Superimposition of anatomic structures
Lesions only appear after a certain amount of bone destruction has already occurred.

Question 11

The buccal object rule is also known as the S.L.O.B. rule. What does SLOB stand for?

Answer 11

Same
Lingual
Opposite
Buccal

Question 12

What does the SLOB rule tell us about an object that we are taking a “shift-shot” of?

Answer 12

When the tube head is moved mesially:

If the object also moves mesially, then the object is on the lingual side of the root. SLob Same=Lingual

If the object moves distally then the object is on the buccal side of the root slOB Opposite = Buccal

Question 13

What is the ideal shift (in degrees) for utilizing the SLOB rule?

Answer 13

20 degrees (Enough to separate objects in question without distorting them)

Question 14

What exactly does the SLOB rule allow for clinically?

Answer 14

Location of additional canals and/or roots
Distinction b/w superimposition of structure
Determination of buccal or lingual position of anatomical features of iatrogenic mishaps.

Question 15

PA images are easily distorted, how can this be accommodated?

Answer 15

Take BW in addition to PA’s in order to minimize elongation or foreshortening

Question 16

What do BW’s do better than PA’s?

Answer 16

Depth of caries
Extent of restorations
Morphology of Pulp Chambers
Presence of Open Margins
Size, position and depth of posts

Question 17

What technique results in the most accurate PA’s

Answer 17

The paralleling technique

Question 18

What does the paralleling technique entail?

Answer 18

Film is placed parallel to the long axis of the tooth and the central beam is directed at a right angle to the film

Question 19

What is it called when the central beam is directed at an imaginary line that bisects the angle between the tooth and the film?

Answer 19

Bisecting Angle Technique

Question 20

When would the bisecting angle technique be used?

Answer 20

To allow for anatomic restrictions, like a shallow palate

Question 21

Is actual tissue destruction better or worse than it appears in the x-ray?

Answer 21

Worse. 12.5% of the cortical plate and/or 7.5% of the mineralized bone has to be destroyed before it appears on the xray.

Question 22

What is the most common mimic of a periapical lesion?

Answer 22

Periapical cemental dysplasia

Question 23

What are the 4 Key Steps of a Differential Diagnosis?

Answer 23

1. Conduct vitality testing
2. Take multiple radiographs from different angles and use SLOB to evaluate
3. For anatomical radiolucencies, the healthy tooth in question should also exhibit and intact lamina dura
4. Knowing anatomy will prevent misdiagnoses

Question 24

Why must we practice reading radiographs?

Answer 24

Learned Skill

Dentists interpret their own x rays

Question 25

What did the Goldman study from the 70s show?

Answer 25

That a group of professionals agreed on the diagnoses less than 50% of the time.

6 months later, the same docs agreed with their own previous diagnoses only 75% of the time

Question 26

What did the follow up study in 2011 show?

Answer 26

That years of experience and familiarity with digital systems is the most important factors of accurate xray reading

Question 27

What are the 4 tools for diagnosis?

Answer 27

1. Chief Complaint
2. History of symptoms
3. Clinical Exam
4. X rays

Question 28

When might a vertical root fracture not show up well on a radiograph?

Answer 28

When the fracture is in the same plane as the radiograph

Question 29

What radiographs are ordered prior to RCT?

Answer 29

2-3
1 Straight Angle
1 Shift shot
+/- BWX

Question 30

What is a WL radiograph?

Answer 30

Working Length

Question 31

What does EAL stand for RE: WL radiographs

Answer 31

Electronic Apex Locator

Question 32

What does MAF stand for

Answer 32

Master Apical File

Question 33

what is an important tip when taking shift shots in terms of consistency?

Answer 33

Always write down what direction the shift was in!

Question 34

What is ALARA

Answer 34

As Low As Reasonably Achievable

Question 35

When is conventional film used

Answer 35

In an emergency when the computer system is down

Question 36

What does CBCT stand for?

Answer 36

Cone Beam Computed Tomography