## 2 Materials and Methods
### Scaffolds  
Scaffolds were used in 81 studies, either as the primary variable of investigation or as delivery vectors for bioactive molecules and cell seeding (Table 4). Most studies used synthetic 3D porous scaffolds of a synthetic polymer, such as beta-tricalcium phosphate, PLGA, PCL, or their combination, to create composite scaffolds.  
### Scaffolds  
Scaffolds were used in 81 studies, either as the primary variable of investigation or as delivery vectors for bioactive molecules and cell seeding (Table 4). Most studies used synthetic 3D porous scaffolds of a synthetic polymer, such as beta-tricalcium phosphate, PLGA, PCL, or their combination, to create composite scaffolds.  
\begin{table}
\begin{tabular}{c c c} \hline
**Scaffold** & **Number of Studies (\%)** & **References** \\ \hline Natural polymers & & \\ \hline Hyaluronic-acid-based & 3 (3.4) & [52; 53; 77] \\ \hline Collagen & 23 (26.1) & [22; 24; 39; 45; 52; 54; 55; 63; 64; 65; 68; 72; 74; 79; 81; 88; 90; 97; 100; 101; 102] \\ \hline Chitosan-based & 6 (6.8) & [49; 59; 76; 87; 99; 100] \\ \hline Synthetic polymers & & \\ \hline PLGA 1 & 15 (17) & [26; 33; 35; 36; 40; 41; 43; 46; 47; 50; 51; 66; 70; 103; 108] \\ \hline PLA-based & 3 (3.4) & [32; 60; 96] \\ \hline PDLLA/CaCO\({}_{3}\)2 & 2 (2.3) & [56; 57] \\ \hline \(<\)PEI 3 & 1 (1.1) & [36] \\ \hline PCL 4 & 7 (8) & [27; 59; 82; 85; 106; 107] \\ \hline PTFE membrane 5 & 1 (1.1) & [94] \\ \hline PU 6 & 1 (1.1) & [93] \\ \hline Bioceramics & & \\ \hline \(\beta\)TCP-based 7 & 12 (13.3) & [30; 35; 43; 44; 45; 69; 78; 85; 86; 90; 93; 107] \\ \hline HAP 8 & 16 (18.2) & [23; 26; 27; 28; 36; 42; 45; 52; 54; 78; 86; 90; 96; 101; 102; 104] \\ \hline Autologous (any tissue) & 3 (3.4) & [34; 67; 84] \\ \hline Xenogenic graft (any tissue) & 3 (3.4) & [36; 83; 109] \\ \hline \end{tabular}
\begin{tabular}{c} When a conjugate scaffold was used, references are placed under both categories for completion. 1 PLGA— poly(lactide-co-glycolic acid); 2 PDLLA/CaCO\({}_{3}\)—poly-dl-lactic acid/calcium carbonate; 3 PEI—polyethylenimine; 3 PCL—polycaprolactone; 5 PTFE—polytetrafluoroethylene; 6 PU—polyurethane; 7 TCP—tricalciumphosphate; 8 HAP—hydroxyapatite. \\ \end{tabular}
\end{table}
Table 4: Overview of scaffold types used for mandibular bone regeneration.  
\begin{table}
\begin{tabular}{c c c} \hline
**Characterization Approach** & **Number of Studies (\%)** & **References** \\ \hline Micro-CT & 35 (39.8) & [24; 27; 30; 33; 35; 39; 41; 43; 45; 47; 49; 51; 62; 65; 69; 76; 80; 83; 86; 88; 90; 93; 99; 102; 107] \\ \hline Histology & 79 (89.8) & [22; 23; 25; 26; 28; 23; 24; 35; 37; 39; 43; 46; 48; 56; 60; 63; 65; 66; 67; 71; 75; 79; 89; 91-94; 97; 102; 103; 105; 106] \\ \hline \
\begin{tabular}{c} Immunohistochemistry \\ \end{tabular} & 28 (31.8) & [30; 35; 36; 41; 46; 50; 52; 57; 60; 61; 64; 67; 72; 73; 76; 83; 86; 88; 92, \\ \hline RT-PCR 1 (mRNA quantification) & 6 (6.8) & [23; 57; 80; 88; 92; 106] \\ \hline Fluorescence microscopy & 4 (4.5) & [53; 54; 72; 109] \\ \hline Biomechanical testing & 11 (12.5) & [24; 28; 37; 38; 42; 63; 73; 74; 92; 102; 103] \\ \hline SPECT 2 & 1 (1.1) & [109] \\ \hline SEM 3 & 10 (11.3) & [37; 38; 59; 64; 82; 83; 86; 90; 107; 108] \\ \hline CBCT 4 & 4 (4.5) & [36; 59; 71; 96] \\ \hline \end{tabular}
\begin{tabular}{c} \({}^{1}\) RT-PCR—reverse transcriptase polymerase chain reaction; 2 SPECT—single-photon-emission computed tomography; 3 SEM—scanning electron microscopy; 4 CBCT—cone beam computed tomography. \\ \end{tabular}
\end{table}
Table 3: Overview of diagnostic modalities used to characterize new bone formation.