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Objective: The combination of anorganic bovine bone (ABB) with platelet-rich plasma (PRP) has been widely used in bone regeneration procedures although its benefits are still unclear. The purpose of this study was to evaluate whether or not PRP improves the efficacy of ABB in sinus floor augmentation. In addition, we have investigated the effect of residual bone height and tobacco on implant survival in sinus augmentation procedures. Pateint and Methods: Eighty-seven patients recruited for this study underwent 144 sinus floor augmentation procedures using ABB alone or ABB plus PRP (ABB1PRP) in a randomized clinical trial. A total of 286 implants were placed in the augmented bone, and their evolution was followed up for a period of 24 months. In order to investigate on a histological level and any adjunctive effects, we performed an ancillary study in five edentulous patients with a symmetrical severely resorbed maxilla. In these patients, a bilateral sinus augmentation was randomly performed using ABB or ABB1PRP in a split-mouth design, and after 6 months, bone biopsies were taken from the implant sites for histological and histomorphometric analysis. Results: Overall, 96.2% of ABB and 98.6% of ABB1PRP implant success were obtained during the monitoring period and differences were not found between sites grafted with and without PRP in the 87 patients studied. Densitometry assessments and graft resorption were similar in both experimental groups. However, the histological and histomorphometrical analysis in the five edentulous patients revealed that bone augmentation was significantly higher in sites treated with ABB1PRP (p40.05). Another outcome from our study is that the lack of initial bone support (p40.05) and smoking (p 5 0.05) appeared to have a negative effect on the treatment success, which was accentuated when both circumstances coincided. Conclusions: PRP is not a determining factor for implant survival in sinus lifting procedures. However, this study revealed that PRP can improve the osteoconductive properties of ABB by increasing the volume of new bone formed. Moreover, in sinus augmentation procedures the implant's survival rate appears to be more influenced by the residual bone height or by tobacco than by the type of bone graft.

Objective: Bone augmentation with the titanium mesh (Ti-mesh) technique is susceptible to a large rate of complications such as morbidity of bone graft donor site, and mesh exposure to the oral cavity. The purpose of this study was to evaluate the efficacy of anorganic bovine bone (ABB) in alveolar bone augmentation with the Ti-mesh technique, as an alternative to autologous bone grafts. In addition, we investigated the effect of platelet rich plasma (PRP) in preventing mesh exposure, by applying it to cover the Ti-mesh. Materials and Methods: The 30 patients recruited for this study underwent 43 alveolar bone augmentation with the Ti-mesh technique using in all of them ABB as graft material. In 15 patients the Ti-meshes were covered with PRP (PRP group) while in the other 15 the Ti-meshes were not (control group). After 6 months, patients were called for clinical, radiographic and histological evaluation, and implant placement surgery. A total of 97 implants were placed in the augmented bone and their evolution was followed up for a period of 24 months. Results: Significant differences were found between the two study groups in terms of complications and bone formation. In the control group 28.5% of the cases suffered from mesh exposure, while in the PRP group, no exposures were registered. Radiographic analysis revealed that bone augmentation was higher in the PRP group than in the control group. Interestingly, mesh exposure seemed to be a risk factor regarding graft resorption and failure. Overall, 97.3% of implants placed in the control group and 100% of those placed in the PRP group were successful during the monitoring period. We suggest that the positive effect of PRP on the Ti-mesh technique is due to its capacity to improve soft tissue healing, thereby protecting the mesh and graft material secured beneath the gingival tissues. Conclusions: Alveolar bone augmentation using ABB alone in the Ti-mesh technique is sufficient for implant rehabilitation. Besides, covering the Ti-meshes with PRP was a determining factor for avoiding mesh exposure in this study. Titanium mesh exposure provoked significant bone loss, but in most cases it did not affect the subsequent placement of implants. Key words: anorganic bovine bone, bone regeneration, platelet rich plasma, titanium mesh, exposure. Clinical Relevance Scientific rationale: Osteoconductive properties of ABB have been described in many bone augmentation procedures with good results, so it seemed reasonable to expect similar outcomes when applied in the Ti mesh technique. Although the use of PRP in bone regeneration is a moot question its effects over soft tissue seems to be clearer. In this study we compare both the efficacy of ABB alone and the effect of PRP over soft tissues in the titanium mesh technique. Principal findings: ABB alone produces sufficient bone volume augmentation for implant rehabilitation and the use of PRP covering the titanium mesh can improve the soft tissue healing over the titanium mesh preventing its exposure. Practical implications:...

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a b s t r a c tOnlay autografting is amongst the most predictable techniques for craniofacial vertical bone augmentation, however, complications related to donor site surgery are common and synthetic alternatives to onlay autografts are desirable. Recent studies have shown that the acidic calcium phosphates, brushite and monetite, are osteoconductive, osteinductive and resorb faster in vivo than hydroxyapatite. Moreover, they can be 3D printed allowing precise host bone-implant specific conformation. The objectives of this study were to confirm that craniofacial screw fixation of 3D printed monetite blocks was possible and to compare the resulting vertical bone augmentation with autograft. 3D printed monolithic monetite onlay implants were fixed with osteosynthesis screws on the calvarial bone surface of New Zealand rabbits. After 8 weeks, integration between the implant and the calvarial bone surface was observed in all cases. Histomorphometry revealed that 42% of the monetite was resorbed and that the new bone formed within the implant occupied 43% of its volume, sufficient for immediate dental implant placement. Bone tissue within the autologous onlay occupied 60% of the volume. We observed that patterns of regeneration within the implants differed throughout the material and we purpose that the cause was the anatomy and blood supply pattern in the region. Rapid prototyped monetite being resorbable osteoconductive and osteoinductive would appear to be a promising biomaterial for many bone regeneration strategies.