Maxillary Sinus Floor Elevation Using Platelet-Rich Plasma Combined With Either Biphasic Calcium Phosphate or Deproteinized Bovine Bone.

PURPOSE: Maxillary sinus floor elevation procedure has the objective of augmenting available bone in atrophic posterior maxilla to allow dental implants placement. The main aim of this prospective study was to evaluate clinically and histomorphometrically the performance of biphasic calcium phosphate (BCP) used in conjunction with platelet-rich plasma (PRP) compared with demineralized bovine bone matrix (DBBM) and PRP in sinus floor elevation surgery. MATERIALS AND METHODS: Patients candidate to sinus floor elevation were treated using either BCP and PRP or DBBM and PRP. Biopsies were retrieved using trephine bur during implant placement surgery 6 months after grafting. Clinical success of implants was evaluated 1 year after prosthesis delivery. Histomorphometric analysis was performed assessing the relative volume of newly formed bone. RESULTS: A total of 20 patients were recruited, and 20 sinus augmentation procedures were performed, 10 for each group. A total of 42 implants were placed. One year after prosthetic loading a 100% implant survival rate was reported in both groups. Histomorphometric analysis revealed that the mean amount of new bone formation was 18.6 ±â€Š3.3% in BCP group and it was 21.9 ±â€Š4.9% in DBBM group, without statistically significant difference. In BCP group a greater amount of collagen type I was found with respect to DBBM group. CONCLUSIONS: Both grafting materials led to an excellent performance regarding implant survival rate after 1 year follow-up, without any significant adverse sequelae. A similar capability of inducing new bone formation was observed in both groups, even though the higher quantity of collagen type I in BCP group may suggest a greater potential for bone formation over time as compared with DBBM.

Platelet-Rich Plasma and Deproteinized Bovine Bone Matrix in Maxillary Sinus Lift Surgery: A Split-Mouth Histomorphometric Evaluation.

PURPOSE: The purpose of this split-mouth controlled study was to evaluate and compare the amount of vital bone after lateral sinus lift surgery using either a mixture of pure platelet concentrate and deproteinized bovine bone mineral (test group) or solely deproteinized bovine bone as grafting material (control group). MATERIALS AND METHODS: Six patients with edentulous posterior maxilla and a residual ridge height of less than 4 mm were recruited in this study. Six months after grafting procedure, 2 bone biopsies per patient were taken bilaterally from the anterolateral sinus wall. Histological and histomorphometrical analysis was carried out. RESULTS: A total of 10 sinus surgeries in 5 patients were analyzed. The mean percentage of vital bone was 22.72% ± 9.21% (range, 11.45%-33.30%) in the control group and 30.70% ± 7.89% (range, 18.30%-39.99%) in the test group. CONCLUSION: The adjunct of pure platelet-rich plasma to deproteinized bovine bone mineral may enhance vital bone formation in the first 6 months after sinus floor augmentation. However, no statistically significant difference was found between groups (P = 0.18).

Animal models for meniscus repair and regeneration.

The meniscus plays an important role in knee function and mechanics. Meniscal lesions, however, are common phenomena and this tissue is not able to achieve spontaneous successful repair, particularly in the inner avascular zone. Several animal models have been studied and proposed for testing different reparative approaches, as well as for studying regenerative methods aiming to restore the original shape and function of this structure. This review summarizes the gross anatomy, function, ultrastructure and biochemical composition of the knee meniscus in several animal models in comparison with the human meniscus. The relevance of the models is discussed from the point of view of basic research as well as of clinical translation for meniscal repair, substitution and regeneration. Finally, the advantages and disadvantages of each model for various research directions are critically discussed.

Osteochondral repair by a novel interconnecting collagen-hydroxyapatite substitute: a large-animal study.

A novel three-dimensional bicomponent substitute made of collagen type I and hydroxyapatite was tested for the repair of osteochondral lesions in a swine model. This scaffold was assembled by a newly developed method that guarantees the strict integration between the organic and the inorganic parts, mimicking the biological tissue between the chondral and the osseous phase. Thirty-six osteochondral lesions were created in the trochlea of six pigs; in each pig, two lesions were treated with scaffolds seeded with autologous chondrocytes (cell+group), two lesions were treated with unseeded scaffolds (cell- group), and the two remaining lesions were left untreated (untreated group). After 3 months, the animals were sacrificed and the newly formed tissue was analyzed to evaluate the degree of maturation. The International Cartilage Repair Society (ICRS) macroscopic assessment showed significantly higher scores in the cell- and untreated groups when compared with the cell+ group. Histological evaluation showed the presence of repaired tissue, with fibroblast-like and hyaline-like areas in all groups; however, with respect to the other groups, the cell- group showed significantly higher values in the ICRS II histological scores for "cell morphology" and for the "surface/superficial assessment." While the scaffold seeded with autologous chondrocytes promoted the formation of a reparative tissue with high cellularity but low glycosaminoglycans (GAG) production, on the contrary, the reparative tissue observed with the unseeded scaffold presented lower cellularity but higher and uniform GAG distribution. Finally, in the lesions treated with scaffolds, the immunohistochemical analysis showed the presence of collagen type II in the peripheral part of the defect, indicating tissue maturation due to the migration of local cells from the surroundings. This study showed that the novel osteochondral scaffold was easy to handle for surgical implantation and was stable within the site of lesion; at the end of the experimental time, all implants were well integrated with the surrounding tissue and no signs of synovitis were observed. The quality of the reparative tissue seemed to be superior for the lesions treated with the unseeded scaffolds, indicating the promising potential of this novel biomaterial for use in a one-stage procedure for osteochondral repair.

In vitro characterization and in vivo behavior of human nucleus pulposus and annulus fibrosus cells in clinical-grade fibrin and collagen-enriched fibrin gels.

The intervertebral disc (IVD) presents a limited self-repair ability and cell-based therapies have been suggested to prevent or treat IVD lesions. Fibrin-based scaffolds as cell carriers are promising candidates in IVD tissue engineering, thanks to their ability to be easily delivered into the defect and to adapt to the lesion shape, to support/retain the injected cells into the implantation site and to favor the production of a suitable extracellular matrix (ECM). We evaluated the in vitro and in vivo behavior of human nucleus pulposus (NP) and annulus fibrosus (AF) cells in a clinical-grade collagen-enriched fibrin that has never been tested before for orthopedic applications, comparing it with clinical-grade fibrin. The survival of IVD cells seeded within fibrin or collagen-enriched fibrin and the ECM synthesis were evaluated by biochemical, immunohistochemical, and transcriptional analyses, prior and after subcutaneous implantation of the gels in nude mice. After 28 days of implantation, NP and AF cells were still detectable within explants, produced tissue-specific ECM, and showed a higher content of glycosaminoglycans (GAGs) and type I and II collagen compared to gels before implantation. Both the fibrin gels, enriched or not with collagen, seemed to be suitable for the culture of AF cells, being able to support the homogeneous synthesis of type I collagen, characteristic of the native fibrocartilaginous AF tissue. Differently, fibrin alone was a more suitable matrix for NP culture, supporting the homogeneous deposition of GAGs and type II collagen. In conclusion, our results suggest to combine AF cells with fibrin, enriched or not with collagen, and NP cells with fibrin alone to maintain the typical features of these cell populations, indicating these clinical-grade materials as viable options in cell-based treatments for IVD lesions.

Repair of osteochondral defects in the minipig model by OPF hydrogel loaded with adipose-derived mesenchymal stem cells.

AIM: Critical knee osteochondral defects in seven adult minipigs were treated with oligo(polyethylene glycol)fumarate (OPF) hydrogel combined with autologous or human adipose-derived stem cells (ASCs), and evaluated after 6 months. METHODS: Four defects were made on the peripheral part of right trochleas (n = 28), and treated with OPF scaffold alone or pre-seeded with ASCs. RESULTS: A better quality cartilage tissue characterized by improved biomechanical properties and higher collagen type II expression was observed in the defects treated by autologous or human ASC-loaded OPF; similarly this approach induced the regeneration of more mature bone with upregulation of collagen type I expression. CONCLUSION: This study provides the evidence that both porcine and human adipose-derived stem cells associated to OPF hydrogel allow improving osteochondral defect regeneration in a minipig model.