NEW YORK – Getting a filling at the dentist can be painful, expensive and generally miserable. A crown or a root canal is even worse. Still, you do it because your dentist says you should.

But in a surprising number of cases, you might have another choice. Where one dentist sees a crown, another might see just a filling. And where one recommends drilling, another might suggest trying some prescription toothpaste first.

In other words, a dentist’s prognosis is not always the final word. Training, personal philosophy and economics can all play a role.

“A dentist who graduates in 2026 versus a dentist who graduates in 1999, they might have two completely different treatment plans,” said Ms Shelbey Arevalo, chief executive of National Dental Advocacy Program, which helps patients navigate the dental healthcare system.

So, how do you know if you have the right prognosis for you, and when should you seek a second opinion? Here is what you need to know.

Cavities (called caries by dentists) are any damage to a tooth’s surface caused by acid produced by bacteria in the mouth. The deeper the decay goes, the bigger the problem. While this may sound clear-cut, it often is not.

If the acid is wearing through the outside enamel but has not got to the next layer of the tooth, called the dentine, then it is a judgment call whether to intervene, said Dr Sara Stuefen, a dentist in Vinton, Iowa, and a spokesperson for the American Dental Association.

“Sometimes, we still have a chance,” she said. Better brushing and flossing, plus cutting back on sweets or coffee, could stop the damage.

“A lot of patients don’t realise that you can reverse a carie when it’s in its earliest stages,” added Dr Diana K. Nguyen, an associate clinical professor of dentistry at the University of California, San Francisco.

Once the decay gets into the softer dentine layer, most dentists will immediately recommend a filling. But even then, approaches differ. Some will use ...