Final answer:
For a mandibular first molar with dental caries but no exposure of pulpal tissues after caries removal, the appropriate treatment is the restoration of the tooth with suitable dental materials.
Step-by-step explanation:
When treating dental caries on a mandibular first molar, if the pulpal tissues are not exposed after caries removal, the treatment of choice is restoration. A pulpotomy is unnecessary because there is no pulp exposure or apparent infection of the pulp.
Root canal treatment is also not warranted in the absence of pulp tissue exposure or symptoms indicating irreversible pulpitis or necrosis. Therefore, the caries should simply be removed, and the tooth structure restored using appropriate dental materials.