## 2 Materials and Methods  
This review was conducted in accordance with the recommendations outlined in the PRISMA Extension for Scoping Reviews (PRISMA-ScRs) guidelines [17], with the corresponding checklist provided as Supplementary Material S1.  
The research question was developed using the PCC framework [18]:  
* Problem (P) = advancements in maxillofacial prosthetics using digital workflows;
* Concept (C) = integration of 3D printing technologies and imaging methods;
* Context (C) = outcomes related to the application of these technologies in soft maxillofacial prosthetic fabrication.  
In this framework, the problem (P) was the need for precise, efficient, and customizable workflows in maxillofacial prosthetics; the concept (C) was the use of advanced 3D printing technologies and imaging techniques; and the context (C) focused on the outcomes, including accuracy, material optimization, and clinical applicability.  
An online search was conducted without any restrictions on the year of publication, up to December 2024. The databases searched included PubMed and Scopus using the following key-words and MeSH Terms in different combinations employing logical operators AND or OR: \"3D printing\", \"additive manufacturing\", \"rapid prototyping\", \"layer-by-layer fabrication\", \"digital fabrication\", \"maxillofacial prostheses\", \"soft prosthesis\", \"silicone\", \"polydimethylsiloxane (PDMS)\", \"direct printing silicone\", \"CAM silicone\", \"elastic polymer\", \"flexible polymer\". A manual search was conducted in notable journals related to prosthetics, including The Journal of Prosthetic Dentistry, Journal of Prosthodontics, Journal of Prosthodontics Research, Journal of Prosthodonics-Implant, Esthetic and Reconstructive Dentistry, Journal of Advanced Prosthodontics, and The International Journal of Prosthodontics. Additionally, the reference lists of the selected papers, gray literature databases, and reviews on the subject were thoroughly assessed to ensure comprehensive coverage of relevant studies. The search strategies used in the two databases are provided as Supplementary Material S2.  
The analysis included only human studies in which directly printed maxillofacial prostheses were obtained, encompassing both in vitro investigations and clinical reports, providing a comprehensive understanding of advancements in this field. Studies focusing exclusively on the manufacturing of ocular prostheses, as well as those utilizing conventional or 3D-printed models, and literature reviews, were excluded.  
The Rayyan platform ([[https://www.rayyan.ai/](https://www.rayyan.ai/)]([https://www.rayyan.ai/](https://www.rayyan.ai/)), accessed on 20 December 2024) was utilized to automatically remove duplicates and review the titles and abstracts of the articles that were retrieved. The article screening process was carried out independently by two researchers ([PERSON] and O.E.B.V.) according to predefined inclusion and exclusion criteria. Any disagreements or lack of consensus were addressed through discussions between the researchers, with the involvement of a third researcher ([PERSON]) serving as a mediator when required. Data extracted from the selected studies included details such as authorship, year of publication, country, type of study, workflow, manufacturing process and part, and other pertinent observations. This information was systematically compiled and documented in an Excel spreadsheet for analysis.