## 3 Results
### Fit Assessment Outcomes
The quantification of the gap between the metal frameworks and the supporting oral structures was done indirectly by the superposition of an impression material followed by thickness calculation (fourteen papers) or directly using the superimposition of the RPD framework and the master cast with CAE techniques (three papers) or after cutting the indirect structures (one paper). In nine studies, the authors evaluated the value of the discrepancy between the produced metal frameworks and the STL design, using superimposition CAE techniques. When the fit accuracy of RPD framework components was measured, the occlusal rest seats were the most mentioned location (seventeen papers), followed by the major connector (twelve papers) (Table 2). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Study**} & \multirow{2}{*}{\begin{tabular}{c} **Fit Assessment** \\ **Method** \\ **(Technique)** \\ \end{tabular} } & \multicolumn{2}{c}{\begin{tabular}{c} **Fit Qualitative** \\ **Constructed** \\ **Outcome** \\ **Outcome** \\ **(Outcome Used)** \\ \end{tabular} } & \multicolumn{2}{c}{\begin{tabular}{c} **Fit Quantitative** \\ **Outcome** \\ **(Thickness \(\mu\)m)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Protocols Studied** \\ **and Fit Results** \\ \end{tabular} } \\ \hline \multirow{4}{*}{\begin{tabular}{c} [PERSON] et al., \\ 2022 [83] \\ \end{tabular} } & QT (Silicone & & & & \\ specimens: Digital & & & & 14 \(\mu\)m) (Superim- & & \\ Gauge, & & & & position & & \\ Superimposition & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \multirow{4}{*}{\begin{tabular}{c} [PERSON] et al., 2022 [84] \\ \end{tabular} } & Q!+QT (Visual & & & & PT1 & \\  & inspection; Silicone & & & (242 \(\pm\) 45 \(\mu\)m) & & PT6 \(\approx\) PT1 \\  & specimens: Digital & & & (274 \(\pm\) 45 \(\mu\)m) & & \\ \hline \multirow{2}{*}{\begin{tabular}{c} [PERSON], 2022 [82] \\ \end{tabular} } & Q! (Patient & & & & \\ satisfaction) & Good (Satisfied) & - & - & - \\ \hline \multirow{4}{*}{\begin{tabular}{c} [PERSON] et al., \\ 2022 [85] \\ \end{tabular} } & QT & & & & PT1 & \\  & (Superimposition) & - & [PERSON], [PERSON], [PERSON] & & (103 \(\pm\) 18 \(\mu\)m) & PT4 \(\approx\) PT1 \\  & & & & & (109 \(\pm\) 21 \(\mu\)m) & \\ \hline \multirow{2}{*}{\begin{tabular}{c} [PERSON], [PERSON] \& [PERSON], \\ 2022 [86] \\ \end{tabular} } & Nd & - & - & - & - \\ \hline \multirow{4}{*}{\begin{tabular}{c} [PERSON], [PERSON] \& \\ [PERSON], 2022 [87] \\ \end{tabular} } & QT (Silicone & & & PT1 & \\  & specimens: & & (170 \(\pm\) 92 \(\mu\)m) & PT1 \(>\) PT6 \\  & Scanning electron & & & PT6 & \\  & microscope & & & (390 \(\pm\) 227 \(\mu\)m) & \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} [PERSON], [PERSON] \& [PERSON], \\ 2021 [88] \\ \end{tabular} } & Nd & - & - & - & - \\ \hline \multirow{4}{*}{
\begin{tabular}{c} [PERSON], [PERSON] \& \\ [PERSON] 2022 [89] \\ \end{tabular} } & QT & & & PT4 (319 \(\pm\) 8 \(\mu\)m) & \\  & (Superimposition & & & PT6 & PT6 \(>\) PT4 \\  & to STL: CAD & - & OcR, MC, Ott & (160 \(\pm\) 11 \(\mu\)m) & \\  & analysis) & & & & \\ \hline \hline \end{tabular}  
* PT: Protocol; Nd, Not described in the manuscript; QI: Qualitative; QT; Quantitative; Micro-CT, Micro-computed tomography; EF, Entire framework; OcR: Occlusal rests; MC: Major connector; OtC: Other components; \(<\), Worse than; \(\approx\), Similar to; \(>\), Better than.  
\end{table} 
Table 2: _Cont._Significant heterogeneity was observed in the fit accuracy quantitative assessment, even when the measured object was the same. The studies that applied the silicone interposition method (fourteen papers) differ in the thickness calculation technique. Analog measurement was done in seven studies, and a stereo microscope or a digital gauge was used in four.