## 4 Discussion
It is a semi-rigid barrier made of cortical bone, and studies have shown that over a slightly longer time than needed by autogenous bone, it resorbs and transforms into new bone, or sometimes it simply integrates into the area where it is applied. In 2022, the modified periosteal inhibition (MPI) technique was presented, which involves the use of a soft cortical lamina instead of a d-PTFE sheet, affixed with a few drops of human fibrin glue (Tisseel). The cortical lamina proved to be able to block osteocl activity outside the alveolus, leading for the first time to control, 4 months after extraction, with increased alveolar volume and without the need to insert biomaterial inside the extraction site. This was possible because the cortical lamina, in addition to inhibiting resorption, creates a horizontal increase in bone thickness, providing support to the soft tissues, which also provides quantitative improvement. In that study, nine extraction sockets treated with MPI demonstrated an average horizontal bone gain of 0.2 mm at 4 months postop. [PERSON] et al. presented a different hypothesis in this regard, suggesting that the detachment of periosteum creates a chamber where the bone forms. This theory accounts for the force of shrinkage exerted by blood clotting in the socket wall caused by the differentiation of fibroblasts into myofibblasts [38]. Two important activities in the healing phase of the extraction socket are explained in this paper: mechanical support of the periosteum and inhibition of myofibblastic activity through quick re-epithelialization of the socket. This second hypothesis of myofibblastic vs. osteocl inhibition can better explain the results achieved with MPI combined with implant placement compared to MPI alone. The same modified periosteal inhibition technique was applied in this study, with simultaneous implant placement and immediate restoration when possible. The Flex (equine) and Soft (porcine) cortical lamina products have expanded the indications for the technique with respect to the use of d-PTFE, including cases with bone fenestration (Figure 10). In a study published by [PERSON] et al. in 2021, cortical lamina was not only found to be effective in preventing reabsorption of the buccal plate, but also made it possible to obtain a horizontal increase in the entire area, giving support to the soft tissue profile, which changed, presenting an aesthetically pleasing vestibular convexity (Figure 11). Immediate provisionalization supports and maintains the interdental papillae; furthermore, the cortical lamina can be cut out by creating triangles that slip under the papillae (Figure 12). The results of this study show that both the Flex and Soft cortical lamina were able to prevent osteolytic activity on the external cortex and counteract myofiblac activity, thus avoiding potential resorption after immediate implant placement without the use of a biomaterial inside the alveolus, in both the anterior and posterior areas. Other studies will be necessary, particularly a multi-center study with a rigorous and repeatable protocol such as the one described here, to confirm and consolidate the excellent results achieved in this case series.