A

Cold testing with a refrigerant spray can reliably transmit temperature change through the metal and porcelain, and studies show it is significantly more accurate than electric pulp testing or other methods on crowned teeth (Miller et al., 2004, PMID 15448461; Almutairi et al., 2021, PMID 34047294). Electric pulp testers give frequent false-positives on metal crowns, heat tests are less accurate, and pulse oximetry cannot penetrate an opaque PFM crown.