Angle of Tip of an endodontic instrument
**Core Concept**
The angle of tip of an endodontic instrument refers to the angle between the long axis of the instrument and the tip of the instrument. This angle is crucial in endodontics as it affects the instrument's ability to engage with the root canal and remove infected dentin.
**Why the Correct Answer is Right**
The correct angle of tip for endodontic instruments is typically between 10° to 20°. This angle allows the instrument to engage with the root canal wall without causing unnecessary damage or ledging. A more acute angle would result in excessive binding and potential instrument breakage, while a more obtuse angle would lead to inadequate engagement and reduced effectiveness.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because an angle of tip of 0° would result in excessive binding and instrument breakage due to inadequate engagement with the root canal wall.
**Option B:** Incorrect because an angle of tip of 30° or more would lead to inadequate engagement with the root canal wall, reducing the effectiveness of the instrument.
**Option C:** Incorrect because an angle of tip of 5° would be too acute, resulting in excessive binding and potential instrument breakage.
**Clinical Pearl / High-Yield Fact**
A good rule of thumb when selecting the angle of tip for an endodontic instrument is to choose an angle that allows the instrument to engage with the root canal wall without causing unnecessary damage, typically between 10° to 20°.
**Correct Answer: C. 5°**