A method for improving 3D intraoral scans performed at home which allows the dental professional to directly fill in any missing 3D image data with pre-existing 3D image data that was previously obtained from the patient. After the at home intraoral scan is completed, the patient transmits it to the dental professional who then reviews it and determines whether or not the at home intraoral scan comprises any missing 3D image data required for producing a complete and accurate 3D model. If the self-intraoral scan is complete, the dental professional may transmit it directly to an appliance manufacturer. However, if the at home intraoral scan is incomplete and comprises missing 3D image information, the dental professional may instead complete the provided scan by comparing it with the reference intraoral scan. The improved scan is then sent to the appliance manufacturer who may then produce the required appliance.