With the use of retainers, about 90% of your correction can be retained. The teeth will not stay exactly where we have placed them. They will make adaptive changes to function in the most efficient manner. This readjustment is not a failure of correction, but a natural change that we have learned to accept in orthodontics.
Since you are only going away for the weekend it should be alright to wait until you return to contact your dentist. No, your retainer shouldn't have become loose after just two weeks.
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