There seems to be some correlation between cavities and children in low income homes. There is likely a number of factors to this, but junk food I believe seems to be one of them.

https://www.cdc.gov/oral-health/php/2024-oral-health-surveillance-report/selected-findings.html

However, maybe more to your point, the issue is also accessibility to healthy foods at reasonable prices. Additionally, likely parent education about how fucking awful soda and candy is.