Which tooth has maximum root surface area?

# Which tooth has maximum root surface area?
A. Maxillary first molar
B. Mandibular first molar
C. Maxillary canines
D. Mandibular central incisors

The correct answer is A. Maxillary first molar 

- Maxillary first molar has maximum root surface area (433 sq. mm) followed by mandibular first molar (431 sq. mm).

- Among posterior teeth, mandibular first premolars have least root surface area. (180 sq. mm)

- Among anterior teeth, maxillary canines have maximum root surface area. (273 sq. mm)

- Mandibular central incisor has the least root surface area of all teeth. (154 sq. mm)

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Ratio of the periodontal root surface area

# Ratio of the periodontal root surface area of the abutment teeth and the teeth to be replaced should be at least:
A. 1:1
B. 2:1
C. 1:2
D. 1:4

The correct answer is A. 1:1

According to Ante's law,  "Periodontal surface area of abutment teeth should be at least equal to the teeth replaced."

Ideal ratio is 2:1

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Reference points in endodontics in posterior teeth

# Reference points in endodontics in posterior teeth are:
A. Buccal and lingual surfaces
B. Pits
C. Cusp tips
D. Marginal ridges

The correct answer is C. Cusp tips.

Gross occlusal reduction should be done on any decayed or filled posterior tooth undergoing root canal therapy.

This reduction should be done before rubber dam placement to check occlusal clearance in all excursive movements. It should be done before the first endodontic treatment, rather than after, in order not to disturb cuspal reference points used to establish proper length of the tooth.

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Palatal root of maxillary first molar is curved:

# 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.

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