When Negative could be Positive.

Highly intriguing research from Stanford here on how negative information supplied during a promotion can have a positive impact on uptake of a product. Apparently the positive aspects become accentuated and make the benefits seem even more positive. Does this approach have a role to play in social marketing for health services? In dentistry a good question is what negatives would one want to drop in while trying to encourage people to visit the dentist? Thoughts welcome.