Is it actually true that cutting back on sugar will help preserve genetically bad teeth?

Yes. But...: ...More action also may be needed. Dental diseases are multi-factorial. Many environmental factors (like sugar ) and genetic factors come into play in the development of disease. Excessive sugar intake is never good for oral health or overall health. But cutting back on sugar alone may not be enough to preserve teeth that have already been damaged or predisposed to disease.

It is true: The health of your teeth relies on a combination of genetics and dental hygiene. Your genes are 60% of your tooth decay. Brushing your teeth twice a day with fluoride toothpaste, flossing them daily, less sugar food and drinks and having regular check-ups with a dentist can help keep your teeth healthy for life.