## 4 Discussion  
The entire world of regeneration has in the last few years been completely directed by the use of biomaterials composed of various scaffolds and grafts with different origins, sizes, and generation technologies [6; 26; 27]. MSCs derived from human dental pulp or periosteum have been used for periodontal regeneration, bone regeneration of atrophic maxilla, and alveolar socket preservation [28]. In the literature, there are several studies showing interesting results for the use of micrografts in tissue regeneration, mainly in dermatology [15; 29], orthopedic reconstruction [30; 31], and cardiac surgery involving the regeneration of ischemic myocardium [32]. Studies that show the potential of this new biomaterial in oral regeneration are not numerous [16; 17; 18; 19; 21; 22; 23; 33]. However, positive results were extracted from eight articles in which micrografts, combined with various scaffolds, were utilized for sinus augmentation, periodontal regeneration, and socket preservation. Micrografts are tissue particles composed of PCs, fragments of extracellular matrix, and growth factors extracted by a mechanical method from various tissues. Given their ease of handling, they could be directly injected into a recipient site or used along with a scaffold such as a collagen sponge or bone grafts to maintain space and lead cells to move forward toward damaged tissue. The mechanical extraction method is an alternative way of isolating stem cells (Figure 2). \begin{table}
\begin{tabular}{c c c} \hline \hline  & \multicolumn{2}{c}{**Sinus Lift**} \\ \hline
**[PERSON] et al. 2017** & **Micro-grafts group** & **Bone substitutes** \\ \hline  & & Hidroxiapatite alone VMT = 20.2 \(\pm\) 3.1\%; NMT = \\ Histological & VMT = 58.5 \(\pm\) 2.5\%; NMT = & 5.5 \(\pm\) 1.6\%; NVMT = N/A; Bovine bone alone \\  & 41.4 \(\pm\) 5.6\%; NVMT = N/A & VMT = 48 \(\pm\) 2.5\%; NMT = 20.5 \(\pm\) 3.1\%; NVMT = \\ Radiographical & High mineralization & High mineralization \\ \hline  & \multicolumn{2}{c}{**Periodontal regeneration**} \\ \hline
**[PERSON] et al. 2018**[19] & **Micro-grafts group** & **Collagen sponge group** \\ \hline Clinical & PD = 8.3 \(\pm\) 1.2 mm; CAL = & PD = 7.9 \(\pm\) 1.3 mm; CAL = 9.4 \(\pm\) 1.5 mm; \\ Radiographical & IBD = 6.4 \(\pm\) 1.4 mm & IBD = 5.6 \(\pm\) 1.0 mm \\
**[PERSON] et al. 2013**[21] & **Micro-grafts group** & **Collagen sponge group** \\ Clinical & PD reduction from 12 to & PD reduction from 11 to 7 mm \\ Radiographical & High mineralization & Low mineralization \\ \hline  & \multicolumn{2}{c}{**Socket preservation**} \\ \hline
**[PERSON] et al. 2009**[22] & **Micro-grafts group** & **Collagen sponge group** \\ \hline Clinical & CAL = 6.2\(\pm\)2.3 mm & CAL = 4.4\(\pm\)1.2 mm \\ Histological & lamellar architecture & immature Bone \\ Radiographical & High mineralization & Low mineralization \\
**[PERSON] et al. 2016**[23] & **Micro-grafts group** & **Collagen sponge group** \\ Clinical & Horizontal reduction = & Horizontal reduction = 30\% Vertical reduction = \\  & 0.60\% & 1.5\% \\ Histological & calcified matrix & organic matrix \\ Radiographical & High mineralization & Low mineralization \\ \hline VMT, vital mineralized tissue; NMT, non-mineralized tissue; NVMT, nonvil mineralized tissue; PD, probing depth; \\ CAL, clinical attachment level; IBD, intrabory defect depth. & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results extracted from test and control sites with follow-up periods of 4 months for sinus lift procedures, 6 and 12 months for periodontal regeneration, and 3 and 4 months for socket preservation. Indeed, the enzymatic technique introduced two decades ago [34] showed incredible results in vitro, but enzymatic digestion with the use of trypsin and collagenase requires a long culture time and various steps of washing and centrifugation procedures. Furthermore, all these processes require a laboratory where cells could be stored and cultured.