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Journal of Oral Science & Rehabilitation No. 1, 2018

S i n u s l i f t a n d M g-e H A/c o l l a g e n-b a s e d s c a f f o l d The graft material investigated in this study was a new generation of HA, biomimetic scaffolds, and was studied as an alternative to overcome the disadvantages of conventional graft mate- rial, simulating bone structure not only from a chemical point of view, but also microscopically, reproducing micropores and their interconnec- tions. Within this graft material category, Mg-e HAs have chemical and morphological properties close to that of natural bone and have showed comparable results to autologous bone in regenerative procedures. This configuration seems to be able to induce migration, adhesion and proliferation of osteoblasts inside the pore network and to promote angiogenesis inside.11 A recent literature review showed the residual bone crestal height to be one of the most critical factor influencing implant sur- vival rate. At the same time, a minimum bone height of 4–5 mm is recommended for a 1-stage implant insertion.16 However, accord- ing to Peleg et al., despite severely resorbed maxillae, a 1-stage surgical technique was adopted in the present study.17 This approach finally reported only 1 implant failure, according to the results obtained by Fugazzotto and Vlassis18 in their retrospective report and according to Wallace and Froum19 and Del Fabbro et al.16 in their reviews. Further- more, in their systematic review, Wallace and Froum indicated membrane placement over the lateral window to be an important factor to improve the quality of regenerated bone.19 An absorbable collagen membrane placed on the buccal sinus wall, in fact, seemed to protect the graft from soft-tissue invasion, which would reduce the amount and the quality of the de novo- formed mineralized tissue.20, 21 This find- ing was also confirmed by a published system- atic review.22 In this study, Pjetursson et al. showed an annual implant failure rate signifi- cantly higher (4.0% vs. 0.7%) when no mem- brane was used to cover the lateral window after the grafting procedure.22 Results from the present study showed that a membrane may not be a critical factor for the implant survival rate. An additional result to be noted is the absence of any postsurgical com- plication in the case of microperforation of the membrane. In fact, sinus membrane perforation is a typical surgical complication. This event could occur during membrane elevation before graft insertion or after graft insertion at the time of implant positioning. According to the litera- ture, the second possibility is often clinically unknown, and it is probably due to membrane compression from the graft shifting subsequent to the implant insertion.12 In order to prevent this complication, an Mg-e HA/collagen-based scaffold with a porous 3-D matrix was placed between the sinus mem- brane and the graft. The clinically relevant pecu- liarity of this scaffold is its appearance, which is similar to that of a collagen membrane, and therefore its similar elasticity. The scaffold was advantageous, preventing perforation of the sinus mucosa by the graft material particles. At the same time, the scaffold acted as not only a membrane but, as demonstrated by the litera- ture,13 also a graft material itself. From a surgical point of view, despite very resorbed maxillae, no postoperative problems or complications were observed when implants were inserted simul- taneously with the graft material. Although the literature describes problems during the surgical phase in sinus augmentation in patients with 1–4 mm residual bone height,23 the use of wide-diameter implants allows a sufficient pri- mary stability.24 Although the mean value of ISQ at T0 was very low, the data reported at T1 are in line with that of previously reported findings. In fact, Lai et al. reported the same findings for rough- surfaced implants installed after minor sinus floor elevation.25 The statistically significant increase of ISQ values between T0 and T1 could be evidence of fast maturation of the graft, after just 3 months. An additional increase between T1 and T2 could indicate a further maturation of the material after 12 months of prosthetic loading. Despite some clinical studies suggesting positive results with the use of RegenOss alone in sinus lift pro- cedures after 6 months,12 controversial out- comes with the use of a soft matrix were reached in the literature.26 In fact, Caneva et al. sug- gested the use of rigid materials to counteract negative pressure during respiration.26 Conclusion The present study, within its limitations, demon- strated that the use of a soft matrix in associa- tion with a graft material allows bone regener- ation without postoperative complications. However, further studies should aim to measure discrepancies between preoperative and long- term postoperative increments using the prom- ising matrix used in the present study. Journal of Oral Science & Rehabilitation Volume 4 | Issue 1/2018 13

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