## 3 Results  
The micrografts in all the studies were combined with a scaffold such as collagen sponge or hydroxyapatite. In the control group, a collagen sponge or hydroxyapatite alone was used (Table 3). Sinus augmentation with micrografts was described in a retrospective study [16] and in two case reports [17; 18], whereas periodontal regeneration was assessed in a randomized clinical trial [19], a case series [20], and a case report [21]. Furthermore, two case series of socket preservation with test and control were published by [PERSON] et al. in 2009 [22] and 2016 [23]. Results regarding periodontal regeneration in the RCT [19] were extracted, and various types of non-containing defects (20% incisive, 13.4% canine, 26.7% premolar, and 40% molar) were treated with micrografts combined with a collagen sponge associated with a minimally invasive flap. Statistically significant results were found in the microgrid group for PD and CAL (\(p<0.001\)), with mean reductions of \(4.9\pm 1.4\) mm and \(4.5\pm 1.9\) mm, respectively, during a 12-month period. A statistically non-significant increase in REC was found (\(0.4\pm 1.1\) mm), whereas in the control group, PD, CAL, and REC were, respectively, \(3.4\pm 1.7\) mm, \(2.9\pm 2.2\) mm, and \(0.5\pm 0.9\) mm. Other interesting data came from a case report [21] where, in a split-mouth approach, micrografts showed a reduction in PD from 12 to 3 mm, in contrast with the control site in which the collagen sponge alone showed a reduction in PD from 11 to 7 mm during a follow-up period of 6 months. The radiographic assessment at 6 months showed greater mineralization of the microgrid site than the control site. Radiological data were extracted from the RCT [19] in which the use of image analysis software (Image), LOCI, University of Wisconsin, NIH, Madison, WI, USA) showed statistically significant differences in intrabony defect depth between the test and control groups. Data were observed at both the 6- (\(p<0.001\)) and 12-month follow-ups (\(p<0.001\)). At 12 months, the mean radiographic bone fill levels were \(3.9\pm 1.5\) mm and \(1.6\pm 1.1\) mm in the test and control groups, respectively. Regarding sinus lift, in a retrospective study [18], radiological follow-up at 4 months showed greater mineralization in the group treated with a microgrid combined with hydroxyapatite than in the two control groups in which hydroxyapatite or deproteinized bovine bone was used alone. Histological and histomorphometric data showed a statistically significant result, with more vital mineralized tissue (\(p<\)0.004) in the group treated with combined microgrid/hydroxyapatite (\(58.5\pm 2.5\%\) with respect to the control group) than in those treated with hydroxyapatite (\(20.2\pm 3.1\%\)) or deproteinized bovine bone alone (\(48\pm 2.5\%\)), and more non-mineralized tissue (\(p<0.003\)) in the group treated with combined microgrid/hydroxyapatite (\(41.4\pm 5.6\%\)) than in those treated with hydroxyapatite (\(5.5\pm 1.6\%\)) or deproteinized bovine bone alone (\(20.5\pm 3.1\%\)). Results for socket preservation come from a multicentric study [23] where samples were collected 45, 60, 90, and 120 days after treatment. Evaluation of the samples treated with periosteum-derived micrografts and collagen alone showed that ossification was much faster in the test group than the control group. In particular, at 45 days, the microgrid group already exhibited bone formation, while the presence of inflammatory cells was evident in the control group; moreover, an increase of mineralized matrix at 60, 90, and 120 days was found, in contrast to the control group where the organic matrix was more evident and no bone formation appeared.