I worked in a very deprived area , the youngest child who had all their teeth out was 18 months. In my area half of all 5 year olds have decay.
The terrible thing is a child who has teeth out or alot of treatment young often becomes phobic and ,all too often, the changes in diet and cleaning are not made so that child is doomed to a life of bad oral health . Just like their parents who eat the same diet and also don't clean well as they believe they all have "weak teeth" and don't believe they can make the changes to give them a healthy mouth.
Very frustratingly we had many stable patients who, during COVID, upped their sugar and snacking and came in with so many holes to be filled. It was not unusual to see an 11 year old with 9 teeth to be filled, or an adult with twelve teeth decayed who doesn't change their diet and by the time you finished their fillings yet more decay had started.
Even in the middle class enclaves the constant snacking on "healthy" raisins, yogurts, granola bars,smoothies,fruit juice causes decay all too often.
With gum disease we know it is linked to so many inflammatory processes like heart disease, diabetes,miscarriages . We also know it can be controlled by lifelong increased oral hygiene. But people don't believe that , they want treatment they believe will cure gum disease when , really , the control is almost entirely in their hands.
Changing people's behaviour is the most difficult thing to do , even more so when you are fighting the tropes of "weak teeth" , "baby tooth calcium away from teeth" , I don't need to use floss/interdental brushes because I use mouthwash , having a scale cures gum disease etc etc etc