From the sound of things, it appears that you may experience some sensitivity, due to the recession. There are really no other contraindications against getting the in-office Zoom, besides the likely tooth sensitivity that you'll face. My recommendation would be for you to try the take-home custom whitening trays provided by your dentist. He/She will provide a highly concentrated whitening gel, but you won't have to worry about the increased sensitivity from the heat of Zoom lamp. Good luck and I hope this helps. Follow me if you have more questions.
Sarah Thompson, DMD