Statement of problem: The optimal method of aligning intraoral scans with facial scans to generate a 3-dimensional (3D) virtual patient remains unclear. Distortions in the alignment of intraoral and facial scans would lead to an inadequate virtual patient representation and, therefore, to inadequate diagnosis and treatment planning.

Purpose: The purpose of this systematic review was to evaluate the available techniques for generating a 3D virtual patient by aligning facial and intraoral scans and to assess their accuracy.

Material and methods: A systematic search was conducted in 3 databases: Medline, Scopus, and Web of Science. A manual search was also conducted. Specific descriptors were used to identify alignment techniques. Two independent reviewers screened titles and abstracts, with a third independent reviewer resolving ambiguities. A qualitative analysis was performed, and interexaminer agreement was assessed using the Cohen kappa statistic.

Results: After screening, 48 of the 2832 identified articles were included for qualitative analysis. They focused on 3 alignment techniques: guided by retracted facial scans, extraoral scan bodies, and perioral intraoral scans. Interexaminer agreement was high (kappa=0.82 to 0.88). Integration techniques guided by extraoral scan bodies, influenced by extraoral scan body design and protocols, showed the best accuracy. The outcome variables for the evaluation of the effectiveness of these protocols were heterogeneous.

Conclusions: Integrating facial and intraoral scans was found to enhance diagnosis and treatment planning by providing essential esthetic and functional parameters. Integration techniques guided by extraoral scan bodies and combination techniques showed higher accuracy, especially for complex implant-supported prostheses or edentulous patients.