In 2009, a study was conducted for the purpose of comparing the effectiveness of two bleaching agents: sodium perborate and 37% carbamideperoxide gel. Thirteen patients diagnosed with “non-vital teeth with traumatic dyschromias” were treated at the Universidad Autónoma de Santo Domingo School of Dentistry, Dominican Republic. The findings showed that both bleaching agents were effective; however, 37% carbamideperoxide worked more rapidly and was easier to administer. Because it comes in individualised pre-measured syringes, the gel is immediately ready for application, thereby giving patients the results they desire in a considerably shorter amount of time. After five years, the 13patients previously treated with the non-vital dental bleaching products were recalled to be re-evaluated for possible reversal of tooth discolouration and the development of cervical resorption. Only four patients came to this follow-up dental visit. In all four of the patients’ radiographic findings, there was a complete absence of external cervical resorption. Three of the patients had reversal of tooth discolouration; however, for one patient there were no observable dyschromias. Regardless of the bleaching agent used, if the patient had poor final dental restoration(s) post-bleaching procedure and a lifestyle counter to the maintenance of proper dental health (i.e. smoking, excessive alcohol consumption, and excessive simple sugar consumption), the dyschromias tended to return.