## 3 Results
### Study Characteristics  
The characteristics of the selected studies are shown in Table 2 and Figure 3. The included studies were published in the English language from 2013 up to 2017. The studies were conducted in China (3) and Brazil (3). Different experimental animal models were tested, including rats (4), rabbits (1), and mice (1). In total, 333 animals were analyzed. As expected, due to the selection criteria, all the studies evaluated critical-size defects to assess the osteogenic capacity of the implanted drug delivery systems. The bone defects were made in the parietal [22; 23; 24], calvaria [8; 18], and femur [25] bones. PLGA-based scaffolds, PLGA-based scaffolds embedding SIM, and no treatment were used in the bone defects. The bone formation was evaluated by histological [8; 23], uCT [18; 24; 25], and radiographic [22] analyses.  
Figure 2: Flowchart of the literature search and selection criteria adapted from PRISMA. References were selected in a two-phase process. Electronic databases (Embase, LILACS, LIVIVO, PubMed, SCOPUS, and Web of Science) and grey literature databases (Google Scholar, Open Grey, and ProQuest) were searched up to September 2022.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Study** & \multicolumn{3}{c}{**Population**} & \multicolumn{3}{c}{**Scaffold**} & \multicolumn{3}{c}{**Outcome Measures**} \\ \hline
**Author (Year)** & \multicolumn{2}{c}{**Total Anti-Analy/Detects**} & \multicolumn{1}{c}{**Control Group**} & \multicolumn{1}{c}{**Test Group**} & \multicolumn{1}{c}{**Animal**} & \multicolumn{1}{c}{**Bone Defect**} & \multicolumn{1}{c}{**SIM Dose per**} & \multicolumn{1}{c}{**PLA/PCA Ratio**} & \multicolumn{1}{c}{**Analysis Meth-**} \\
**Country** & \multicolumn{1}{c}{**(n/n)**} & \multicolumn{1}{c}{**(n)**} & \multicolumn{1}{c}{**(n)**} & \multicolumn{1}{c}{**Model/Bone**} & \multicolumn{1}{c}{**Dimension**} & \multicolumn{1}{c}{**Scaffold**} & \multicolumn{1}{c}{**(mm)**} & \multicolumn{1}{c}{**Time**} & \\ \hline \multirow{9}{*}{[PERSON] et al. (2013) [23]; (23); Brazil} & \multirow{3}{*}{32/64} & \multirow{3}{*}{Blank control (n = 32)} & PLGA & \multirow{3}{*}{Wistar (n = 16)} & \multirow{3}{*}{S5.25 mm} & \multirow{3}{*}{20 \(\mathrm{\SIUnitSymbolMicro}\)/Canadian} & \multirow{3}{*}{50-50} & \multirow{3}{*}{\
\begin{tabular}{c} Histological \\ analysis/28 and \\ 56 days. \\ (\(p\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\(\)\) \\ \end{tabular} } & \multirow{3}{*}{
\begin{tabular}{c} **Main Findings** \\ group \\ \end{tabular} } \\  & & & & & & & & & \\ \cline{1-1} \cline{6-10}  & & & PLGA-HA- & & & & & & & \\ \cl  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Study** & \multicolumn{3}{c}{**Population**} & \multicolumn{3}{c}{**Scaffold**} & \multicolumn{3}{c}{**Outcome Measures**} \\ \hline
\begin{tabular}{c}  
Description of items:  
1. Sequence generation (Was the allocation sequence adequately generated and applied?).
2. Baseline characteristics (Were all the animals similar at baseline [age, sex, weight]?).
3. Allocation concealment (Was the allocation adequately concealed?).
4. Random housing (Were the animals randomly housed during the experiment?).
5. Blinding (Were the caregivers and/or investigators blinded from knowledge which intervention each animal received during the experiment?).
6. Random outcome assessment (Were animals selected at random for outcome assessment?).
7. Blinding (Was the outcome assessor blinded?).
8. Incomplete outcome data (Were incomplete outcome data adequately addressed?).
9. Selective outcome reporting (Are reports of the study free of selective outcome reporting?).
10. Other sources of bias (Was the study apparently free of other problems that could result in high risk of bias?).