Keep it clean. A retainer in and of itself does not cause decay. Bacteria feeding on the debris in your mouth will cause decay. Your teeth need hygiene (need to be brushed and flossed), and to do this, you must remove your retainers. Your retainers also need to be clean, as any food or debris will make the decay bacteria very happy. You don't want that. Clean your retainers also. .
No. It is the bacteria and acids in your mouth that cause cavities. Itis even more important to keep your teeth clean by brushing and flossing well now that you are wearing a retainer because a retainer wil ageist easier for these bacteria to accumulate. Keep your retainer and teeth clean and see your dentist regularly for exams and cleanings.
No. Retainers or mouthguards don't cause cavities . Poor oral hygiene causes cavities.
Only if food gets ca. Only if food gets caught and not cleaned out well.
It doesn't help. The retainer itself isn't the cause but it increases your chances of getting cavities by sitting against your teeth. The main reason people get cavities is too much sugar consumption and bad brushing/flossing habits. If you take your retainer out and clean it after meals, brush thoroughly twice daily, floss daily, and reduce your sugar intake you should be able to prevent cavities from forming.