# Palatal root of maxillary first molar is curved:
A. Mesially
B. Buccally
C. Lingually
D. Distally
The correct answer is B. Buccally.
Palatal root of upper first molar is often curved buccally at apical third. It has the largest diameter and offers easiest access of all the three roots.
# Root canal of maxillary first molar difficult for instrumentation is:
A. Mesiobuccal
B. Distobuccal
C. Distolingual
D. Mesiolingual
The correct answer is A. Mesiobuccal.
Mesiobuccal root has greatest distal curvature and is narrowest of all the three roots. It is flattened in mesiodistal direction. Sometimes, it contains a fourth canal.
# In a cavity to be restored with GIC, it should be conditioned with:
A. Water
B. Polyacrylic acid
C. Phosphoric acid
D. Hydrochloric acid
The correct answer is: B. Polyacrylic acid.
-Following completion of any cavity, there will be a smear layer left on the surface and floor.
- To remove this smear layer, 10% polyacrylic acid is applied and allowed to remain in place for 10 seconds.
# Most common cause of endodontic failures in maxillary first molar is:
A. Missed fourth canal
B. Vertical root fracture
C. Periodontal involvement of pulpal lesion
D. None of the above
The correct answer is A. Missed fourth canal.
- It's a standard to mention now that's maxillary first molar has fourth canal, the MB2 in 54% of cases.
- The mandibular first molar is the tooth which needs RCT most commonly, but it's the maxillary first molar which has the most number of failed RCT.