A beautiful model – let us call her Mel – bites into an ice cube and winces in pain. The pain is so severe that she becomes temporarily colour-blind. The world is now a monochrome dystopia of momentary dental discomfort.
Some time passes, and an equally glamorous friend of hers – let us call her Joanne – notices her wincing in pain as she slurps boiling hot liquid through her teeth – as it would behoove a horse to do at a trough...that is if horses drank coffee.
Joanne suggests to Mel Sensodyne toothpaste. Mel goes home that night and brushes her teeth with Sensodyne. This has the effect of instantly curing her colour-blindness. In time we see her slurping coffee through her teeth to her heart’s content , and munching upon ice-cubes with reckless abandon. Everyone lives happily ever after.
In my view, teeth are meant to be sensitive to hot and cold: that is why one’s teeth contain nerves. On the other hand, finger nails are not supposed to be sensitive to hot and cold, as finger nails do not contain nerves. If your finger nails should happen to be sensitive to hot and cold, then seek medical attention immediately: there is something seriously wrong with you!