A brief 15 minute session is required during which impressions of your teeth are taken.  From these impressions, customs trays are fabricated of a thin thermoplastic material which will gently fit over the teeth.  A whitening gel is applied within the trays and inserted into the mouth onto the teeth for a predetermined amount of time and number of sessions.  The usual treatment consists of 1 or 2 45 minute sessions per day for a period of 7 to 14 days.