Are there any negative effects of acrylic dental retainers?

Generally, no.: As is the case with any therapeutic endeavor, treatment of any kind can come with risk if it's not properly implemented. A skillfully made orthodontic retainer presents little risk. There can theoretically be an allergic reaction to the acrylic in an orthodontic appliance. But this type of event is extremely rare. Keeping the appliance and teeth clean will minimize the onset of new tooth decay.

Minimal: Acrylic retainers or any dental prosthesis for that matter does increase your risk for getting cavities and gum disease around the teeth involved. Good oral hygiene is important and cleaning the retainer regularly is important as well. Try not to eat too many sugary or acidic foods as this will also increase your risk for cavities. The benefit of the retainer is that your teeth will stay in place.

No: Unless your allergic to them otherwise no , although make sure you keep them clean

Rarely: Some people are allergic to acrylic and should not use acrylic retainers. Most problems with acrylic retainers are due to either poor fit or poor hygiene.

Usually no: It's rare, but some people have an allergic response to the acrylic (plastic) part of the retainer. If so, see your orthodontist. Keep retainers spotlessly clean to avoid bacterial insult to the teeth or fungus insult to the soft tissues (brush rest 2x/day, soak in denture cleaner 1x/day). Generally they are innocuous.

Retainer Allergy: Some retainers are constructed of acrylic to which some patients may have allergic reaction. Ask your orthodontist dentist to order Essix or Vivera type.