You're about to enter the professional world and enter a field where you are given a lot of trust and autonomy. On a daily basis you will have to make ethical decisions as you decide how you present information to patients, colleagues, insurance companies, and other health care providers.
Id strongly recommend that you decide ahead of time to always be honest, even when it seems that not much is on the line. Pre-deciding becomes a part of your character and will decide what you do when you're under pressure.
Sorry for the ethics lesson, you'll get plenty of that in dental school, but protecting the image of the community is something we take really seriously. The family dentist used to be somebody that you could trust, but in recent years Dentistry's image has suffered due to plenty of fraud and dishonestly.
Someone who lies to get into school will probably lie and cheat to get through school. The same people will continue to be dishonest as dentists. Nows the time to form good habits and build character which is the best practice builder.