## 4 Discussion  
This study aimed to evaluate the stability of the regenerated bone obtained with this technique, involving the application of a porcine bone lamina and bone particulate: only 9 of the 30 implants revealed minimal marginal bone loss. In addition, implants inserted in the regenerated bone bore loading of zirconia single crowns up to three elements fixed-partial-dentures, and all implants survived after a follow-up of 2 years. These data agree with the systematic review by [PERSON] et al. that there are no statistically significant differences between the native and regenerated bone in terms of survival and implant success [19]. The results found seem to reveal bone laminas as a valid and stable method to treat horizontal and vertical bone defects, in line with what the previous limited literature has stated: only a few studies have evaluated the clinical and histological outcome of this biomaterial. Some authors of the current study used the same protocol in a parallel case study, except for micronized filling (200-300 \(\upmu\)m), but revealed faster resorption and reduced graft stability [16]. [PERSON] et al. [21] have reported a success rate of 94.7% among several regenerative procedures in which Lamina was adopted and, after a 1-year follow-up, all but one of the implants placed in the regenerated defects survived, with a survival rate of 97.1%. Only a few previous studies have provided a histological analysis of GBR performed with bone laminas, and this is the first to have conducted a histomorphometric analysis. The results are in line with previous articles [21; 22] in which, after a healing time between 6 and 12 months, new bone was formed in the apical extension of the defect, while, in the coronal extension, melted and highly vascularized connective tissue was formed. More mineralized bone was observed in the apical portion of the defect compared to its coronal extension. This finding could be related to the porosity of the membrane that allowed the growth of vascular cells, which is also frequent in other regenerative procedures employing non-resorbable membranes [23]. The formation of new vessels and the absence of foreign body reactions demonstrate that the lamina is biocompatible. Moreover, in the study of [PERSON] et al., at 6 months after GBR the lamina had not been completely resorbed but replaced primarily by cortical bone [22]. At the time of implant placement, 8 months after the regenerative procedure, the lamina was undistinguishable from the native bone and had been entirely resorbed. Therefore, as revealed by the histomorphometric analysis, the stability allowed the osteeconductive biomaterial to fill the defect with new sound bone. The slow resorption time of these membranes makes them suitable for vertical and horizontal regenerative procedures; while resorbable collagen membranes are rapidly resorbed by the host's immune system [24; 25], the lamina can support the flap and protects the graft for a longer time. While no study has defined the resorption time needed for resorbable membranes, a barrier effect of up to 6 months is desirable, and many collagen barriers fail to achieve this objective [26]. On the other hand, non-resorbable membranes are more challenging to use and, while particularly efficient in vertical bone defects [27; 28], are associated with a higher risk of complications, such as flap dehiscence, membrane exposure, and membrane infection, which can compromise the entire procedure if not adequately treated [29; 30]. Patients were monitored and treated during the follow-up to maintain FMPS and FMSS \(\leq\) 20%. This is a routine practice in our clinic to control the occurrence of mucositis and peri-implantitis, but it allowed us to keep the sample and, thus, the data collection homogeneous.