Fluoride does a good job of preventing decay. Don't go overboard, especially with kids at risk of "fluorosis" but fluoride toothpaste & fluoride mouthwash both seem to help prevent caries/cavities.
This is the kind of rinse I usually get, but I think the primary thing to check is the amount of fluoride. (The branding doesn't seem to correlate with this number at all 🤷)
⚠️ Also: acid softens tooth enamel, so don't brush your teeth right after drinking orange juice or other acidic foods.
My new dentist recommends that I use a toothpaste with a Rx level of fluoride that I pick up at their office during my bi-annual cleaning, and they also do fluoride treatments every visit which had originally been a thing when I was a kid, but which my other dentists stopped when I became an adult.
✨Also (unrelated to cavities/fluoride): if you're in a pinch and you need to polish a piece of jewelry, try rubbing toothpaste on it and then rinsing and then drying with a soft clean cloth. (spot test first, if you can!)
Authors' conclusions
This Cochrane Review supports the benefits of using fluoride toothpaste in preventing caries when compared to non‐fluoride toothpaste. Evidence for the effects of different fluoride concentrations is more limited, but a dose‐response effect was observed for D(M)FS in children and adolescents. For many comparisons of different concentrations the caries‐preventive effects and our confidence in these effect estimates are uncertain and could be challenged by further research. The choice of fluoride toothpaste concentration for young children should be balanced against the risk of fluorosis.
Cochrane Review: Fluoride Mouthrinses
This review “ included 37 studies in which more than 15,000 children (aged six to 14 years) were treated with fluoride mouthrinse or placebo (a mouthrinse with no active ingredient) or received no treatment.” 57 Key results from the study “confirmed that supervised regular use of fluoride mouthrinse can reduce tooth decay in children and adolescents. Combined results of 35 trials showed that, on average, there is a 27% reduction in decayed, missing and filled tooth surfaces in permanent teeth with fluoride mouthrinse compared with placebo or no mouthrinse. This benefit is likely to be present even if children use fluoride toothpaste or live in water-fluoridated areas. Combined results of 13 trials found an average 23% reduction in decayed, missing and filled teeth (rather than tooth surfaces) in permanent teeth with fluoride mouthrinse compared with placebo or no mouthrinse. No trials have looked at the effect of fluoride rinse on baby teeth. We found little information about unwanted side effects or about how well children were able to cope with the use of mouthrinses.” The reviewers concluded "Regular use of fluoride mouthrinse under supervision results in a large reduction in tooth decay in children's permanent teeth. We found little information about potential adverse effects and acceptability." Therefore, fluoride mouthrinses can be effective in caries prevention. In our best clinical judgment it may be that patients using fluoridated toothpastes who are at risk of caries may be candidates for the additional benefits of a fluoridated rinse.