The effect of build orientation on the marginal and internal fit of 3-D printed provisional fixed dental prosthesis: a systematic review and meta-analysis

The present systematic review and meta-analysis aimed to evaluate the effect of build orientation on the marginal and internal fit of 3D-printed provisional fixed dental prostheses. Electronic searches of four databases were conducted to identify studies assessing how build orientation affects the fit of 3D-printed provisional FDPs. This review was structured and drafted based on the guidelines provided by the PRISMA. Prior to commencement, the research protocol was officially registered with PROSPERO. This review sought to answer the following PICO question: Do provisional fixed dental prostheses (P) fabricated using 3D printing at non-zero build orientations (I) demonstrate same marginal and internal fit (O) to those produced at a zero-degree build angle (C)? Quality analysis was performed using the modified CONSORT scale. The initial search yielded a total of 931 titles. Ten studies met the selection criteria and were subjected to qualitative analysis. Four out of ten studies were included in the meta-analysis. Most of the studies possessed a moderate level of quality base on the quality analysis. The GRADE Approach, used to assess the certainty of evidence in the selected articles, reported a moderate level of certainty in the included studies. In general, the specimens printed at zero degrees displayed a better internal and marginal fit, although discrepancies at other angulations were within clinically acceptable limits. Due to limited study pool of highly di-verse, the findings of this review must be viewed cautiously.