You're perfectly fine. They will not think you're lying or hiding anything.
You have a few options here, when filling out secondaries/supplementals whether at home or at the interview, there may be questions regarding courses in progress, planned, or pre-reqs unfinished, etc. This is where you can list your courses that you didn't put down.
Know that the majority of dental schools will require you to submit all transcripts directly to them if you are accepted and decide to attend.
Your other option (you can do both of course), is to utilize the Academic Update period for your AADSAS application. This is when you can update schools, classes, etc. This cycle it will occur on:
November 16, 2012 to February 1, 2013.
http://www.adea.org/dental_educatio...es/AcademicUpdate-UpdatingyourCoursework.aspx
As a personal anecdote for you: I took biochemistry last summer from a school I'd never attended previously, I did not even know I was going to attend that school when I'd submitted my application. I did however have a chance to mention the school and the class in several supplementals and at interviews. I did not make use of the academic update for AADSAS for this (it wouldn't have made a difference at this point). The schools didn't care that it wasn't on my AADSAS application, they expect and encounter this sort of thing EVERY cycle. They just want to know if you're missing pre-reqs and what you're doing about it. And of course that you submit your transcripts in finality before you matriculate at the dental school you're accepted to, if in fact you are so lucky.
Hope this helps.
