The aim of this systematic review was to assess the effect of printing orientation and layer thickness on the accuracy of three-dimensional (3D)-printed fixed dental restoration. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and used the PICO strategy (Population/Patient, Intervention, Comparison, and Outcome). Electronic searches were carried out in July 2025 across PubMed and Scopus, followed by study selection and data extraction. The methodological quality and risk of bias of the included studies were assessed using a modified CONSORT checklist. A total of 11 studies met the inclusion criteria, all of them presenting a moderate risk of bias. The findings indicated that both printing orientation and layer thickness significantly influence the dimensional accuracy, including trueness and precision, as well as internal and marginal adaptation of 3D-printed restorations. The build angle and layer thickness influence the dimensional and fit accuracy of 3D-printed fixed dental restorations. Due to heterogeneity of the studies, an optimal combination of parameters cannot currently be established.
Mesbahi et al. (Sun,) studied this question.