frequent burping?

I tested positive for h. pylori this summer.  I took the antibiotics and have since had two retests that were both negative.  Since that time I've had an issue with fairly constant burping during the day.  Since that time I have also gotten a palate expander from the ortho.  I went to the GI doctor and he believes it is probably from the expander (swallowing air somehow) and didn't look further into any GI problem but gave me prevacid.  Anyone had any experience with this either after h. pylori eradication or from a dental appliance?

[Caryopteris]

I suspect it is from swallowing air, but a prebiotic may help after the antibiotic for H. pylori.  People like Align, for instance.