Question 222 · LDEK · Access and canal preparation
In which of the following scenarios it is necessary to retake the radiograph with the instrument for the purpose of working length determination?
1) tip of the instrument is 4 mm before the radiographic apex;
2) tip of the instrument goes beyond the apex and is located 3.5 mm further from the radiographic apex;
3) tip of the instrument is located 1.5 mm from the anatomical apex;
4) tip of the instrument is exactly at the radiographic apex.
The correct answer is:
2) tip of the instrument goes beyond the apex and is located 3.5 mm further from the radiographic apex;
3) tip of the instrument is located 1.5 mm from the anatomical apex;
4) tip of the instrument is exactly at the radiographic apex.
The correct answer is:
- A. only 1.
- B. only 2.
- C. 1,2.
- D. 2,3.
- E. 3,4.
Hint
Consider how far from the apex a file tip can be before a simple arithmetic correction becomes unreliable.
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