According to Live Science, sensitivity is a defense mechanism we’ve developed to protect damaged teeth from further injury. Teeth have three layers, only one of which — the innermost layer or “pulp” tooth — has blood vessels and nerves.
Learn more about tooth pain at https://www.livescience.com/why-teeth-feel-pain.html

Protect your teeth with 7 tips, including brushing with light, gentle motion every day, using an electric toothpaste for better cleaning, seeing your local dentist regularly, using a straw for drinks, and wearing a night guard if you grind your teeth.

Find tips at https://www.mentalfloss.com/article/76352/7-tips-healthier-teeth