**Question:** In the mandibular arch, first preference major connector for tooth-supported RPD is:

A. Central incisor
B. Canine
C. Premolar
D. Molar

**Core Concept:** A removable partial denture (RPD) is a dental prosthesis that replaces one or more missing teeth in a natural-looking and functional manner. Major connectors are essential components of an RPD, providing stability and retention to the denture. In the mandibular (lower) arch, the first preference for major connectors is determined by their function and support capacity.

**Why the Correct Answer is Right:** The correct answer is D. Molar, because molars have a higher support capacity due to their larger size and more extensive periodontal support. This enables them to distribute the forces generated by mastication more evenly, preventing excessive stress on the remaining teeth and supporting tissues.

**Why Each Wrong Option is Incorrect:**

A. Central incisor (Option A): Central incisors are too small and have limited support, making them unsuitable for major connectors in the mandibular arch.
B. Canine (Option B): Although canines are strong teeth, they are not as stable as molars, which limits their suitability as major connectors.
C. Premolar (Option C): Premolars have a similar size to canines and are not as stable as molars, making them less suitable for major connectors in the mandibular arch.

**Clinical Pearl:** The choice of major connectors is crucial for the success and longevity of an RPD. In the mandibular arch, selecting molars as major connectors ensures optimal distribution of forces, reducing the risk of tooth movement or damage to adjacent teeth and periodontal tissues.

**Correct Answer:** D. Molar

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In summary, the correct answer is D. Molar because they provide the highest support capacity among the given options, ensuring stability and longevity of the removable partial denture. Selecting molars as major connectors distributes the forces generated during mastication more evenly, reducing the risk of tooth movement or damage to adjacent teeth and periodontal tissues. This clinical pearl highlights the importance of considering the size, stability, and support provided by different tooth types when deciding on major connectors for a removable partial denture in the mandibular arch.