Which nerve supplies the upper first molars?

The upper first molars are primarily innervated by the posterior superior alveolar nerve, which branches from the maxillary nerve (V2). This nerve provides sensory innervation to the maxillary molars, delivering the sensation of pain, temperature, and touch. Additionally, the roots of the upper first molars are sometimes also supplied by the middle superior alveolar nerve, which can vary among individuals, but the primary source is indeed the posterior superior alveolar nerve.

The posterior and middle superior alveolar nerves together effectively supply sensation to the upper first molars, accounting for the variant innervations of these teeth. Understanding the anatomy and variations in dental innervation is crucial for procedures like extractions or anesthesia administration in dental practice, as it ensures adequate pain management and procedural success.