## 2 Materials and Methods  
This systematic review assumed the orientations of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Statement [33; 34]. The proposal for the study was registered at the National Institute for Health Research, International Prospective Register of Systematic Reviews (PROSPERO) platform with the number CRD42022354848 (File S1). An electronic search for relevant publications until December 2022 was conducted in the Web of Science and PubMed/MEDLINE databases, using the keywords \"Removable partial denture\" and \"Removable dental prosthesis\". Each of these words was associated with the terms \"digital OR CAD-CAM\", \"Intra-oral scanner OR Digital Impression\", \"computer design OR virtual design\", \"additive manufacturing OR rapid prototyping\", \"Mill\", \"Resin Pattern OR Intermediate structure\", \"Selective laser sintering OR selective laser melting OR direct metal laser sintering OR electron beam melting\", \"Stereolithography OR fused deposition modeling OR digital light processing OR selective deposition modeling OR 3D printing OR 3D jet\", and \"fit OR accuracy\". Due to the scarce literature on RPD metal framework production with digital techniques, case reports, in vitro studies, and clinical studies were included in the search. A manual search of the references used in the included publications was performed to reveal additional relevant manuscripts. Two reviewers ([PERSON], CBN) independently screened citations and abstracts to detect articles that might fulfil the eligibility criteria. Full-text versions of these articles were then obtained and individually assessed by the same reviewers to ascertain their alignment with the criteria. Discussions involving a third reviewer ([PERSON]) resolved any disparities in judgments about study suitability. The same methodology was applied in the data collection process. The publications included met the following criteria: (1) contained relevant data concerning the total production of RPD metal framework with at least one clasp; (2) applied at least one digital technique in the production of the RPD metal framework; and (3) were written in the English language. Studies were excluded if they (1) included partial dentures with a material other than metal; (2) were literature or systematic reviews and experts' opinions; (3) production of RPD combined with fixed prostheses; or (4) did not contain any relevant data on RPD production. During the analysis of the complete manuscripts, information was collected in a data extraction form and organized according to the following features: study design, sample size, and level of scientific evidence; techniques (and details such as equipment or software used) for information acquisition, analysis and design, intermediate structure production and metal framework fabrication; type of metal, and production protocol; and methods for fit assessment of RPD metal frameworks, fit qualitative outcome, fit assessment location, fit quantitative outcome, and comparison between production protocols. Each study's scientific evidence level was classified using the Levels of Evidence Table defined by the Oxford Center for Evidence-based Medicine [35]. Category 1 included systematic reviews of randomized trials. Clinical trials, randomized, and non-randomized clinical studies were grouped in category 2. Category 3 assembled cohort studies. Case-control studies, case series, and case reports comprise category 4. Finally, category 5 incorporated mechanism-based reasoning. The production protocols used in each study were indicated through a classification created by the authors (Figure 1). Eleven categories were constructed according to the different combinations of digital and conventional techniques used in the four steps of the metal framework production (\"information acquisition\", \"analysis and design\", \"intermediate structure production\", and \"metal framework fabrication\").