Congenitally missing lateral incisors creates an esthetic problem with specific orthodontic and prosthetic considerations. Our goal is to analyse in vivo and in vitro the clinical performance of esthetical in MLIA orthodontic cases, as well as the treatment with direct composite additions and with resin-bonded bridgework in patients with dental agenesis of the maxillary lateral incisor, following orthodontic treatment to close or open the missing tooth space. Furthermore, we aim to develop an efficient virtual prototyping method to compare different preparation designs of resin-bonded bridgework. Bisphenol-A (BPA) has recently been shown to have endocrine disrupter action as an environmental hormone. For this reason, we also intend to monitor the presence of this monomer in artificial saliva storage and biological fluids collected before and after adhesive rehabilitation of young patients. We expect to obtain not only satisfactory esthetical and functional results with both techniques, but also consider them as a non-provisional approach.