Is it okay to use a dental mouth guard if i have 2 missing teeth and unfilled cavities teeth?

Probably!: It is okay to use a mouthguard if you have missing teeth. Unfilled cavities could progress much quicker during the use of mouth guards so you should be very diligent and proactive with oral hygiene.

Yes it is: In your case it is safe to use a mouthwash that contain fluoride. The american dental association doesn't specifically recommend using mouthwash in your daily routine, but it does acknowledge its benefits. However, brushing and flossing would be much more beneficial for you.

Yes: Yes it is fine, but i hope it is a custom fit guard made by your dentist. Further, you should address those unfilled cavities. Also, be certain that your teeth are cleaned before wearing your dental guard to keep the bacteria levels down in your mouth.

Yes but...: It would be best to have the unfilled cavities fixed first. The guard can be made either way; however, i would not leave untreated cavities for very long. If you can do it i would get the missing teeth replaced as well prior to the guard; this would be the best plan, again, if you can do it. Decay and missing teeth can lead to more extensive and expensive solutions.

For what reason?: The first step in comprehensive care is to eliminate infection. Cavities should be treated immediately so that they do not progress. Know that if you have a sports mouth guard made, or a night guard for TMJ problems, as teeth are restored or replaced the guard will have to be adjusted or, more likely, remade. Please work with your Dentist to establish a comprehensive treatment plan.