Ozone has been used in European dentistry for decades, and the reason is simple: it's one of the most powerful antimicrobials that exists, and it leaves nothing behind. Ozone occurs naturally in the world. It's made of three oxygen molecules that break down into oxygen radicals, and those radicals are what target bacteria.
Medical-grade ozone (O3) is applied as a gas, as ozonated water, or as ozonated oil, directly to the area being treated. It targets the bacteria responsible for cavities and gum disease on contact, without harming the healthy tissue around it. Your body breaks ozone down into regular oxygen, so nothing synthetic is left behind.
One thing to be clear about: ozone supports treatment, it isn't the treatment on its own. It will not cure an infection or reverse gum disease by itself. What it does do is help sterilize a tooth before a filling goes in, support healthier gums, and aid healing after an extraction, always alongside the actual care the situation calls for.