Fight the film on your teeth for ten days
The pattern
This still is filed under If-then promise.
Define
A conditional contract: if you do this, you get that. The sentence can be tested against the reader's own case.
Mechanism
Specificity does the persuading. The if names the action. The then names the outcome. Hedging kills it.
Verdict
We can name both the action and the result without adjectives
Why it works
The headline is a command with a deadline baked into it, which converts a vague habit change into a finite experiment the reader can say yes to. Fight is an active verb that recasts hygiene as a contest against a named opponent, and ten days sets the exact window in which the reader will judge the result, which is also the window the free tube covers. The Protect the Enamel box is a pre-emptive objection handler placed where a sceptic's eye falls, answering the abrasive-grit worry before it can stop the coupon. The romantic photograph carries the reward silently so the copy is free to stay entirely mechanical.
Steal this when
Use this when your product needs a behaviour change and the proof only shows up after repeated use: name the exact trial length in the headline, cover that length with the free sample, and put the single biggest objection in a box beside the copy.