1) Get a CPA account that has a free trial for a teeth whitening product available. These offers pay anywhere from $20 to $35 per lead.
2) Setup a dentist office template on a domain that you have registered. Example: yourdentistsnamedds.com etc.
3) Post some job ads on a classified ads website such as CL, BP etc. asking for an admin/secretary for a dentist office.
4) When the emails come in, reply back telling them that as part of their benefits package for the job they get free teeth whitening. Use your affiliate link to the teeth whitening offer.