Efficacy of platelet concentrates in bone healing: A systematic review on animal studies - Part B: Large-size animal models.

In the presence of large bone defects, delayed bone union, or nonunion and fractures, bone reconstruction may be necessary. Different strategies have been employed to enhance bone healing among which the use of autologous platelet concentrates (APCs). Due to the high content of platelets and platelet-derived bioactive molecules (e.g., growth factors, antimicrobial peptides), they are promising candidates to enhance bone healing. However, both preclinical and clinical studies produced contrasting results, mainly due to a high heterogeneity in study design, objectives, techniques adopted, and outcomes assessed. The aim of the present systematic review was to evaluate the efficacy of APCs in animal models of bone regeneration, considering the possible factors that might affect the outcome. An electronic search was performed on MEDLINE and Scopus databases. Comparative animal studies with a minimum follow up of 2 weeks, at least five subjects per group and using APCs for regeneration of bone defects were included. Articles underwent risk of bias assessment and quality evaluation. Fifty studies performed on six animal species (rat, rabbit, dog, sheep, goat, mini-pig) were included. The present part of the review considers studies performed on small ruminants, dogs, and mini-pigs (14 articles). The majority of the studies were considered at low risk of bias. In general, APCs' adjunct positively affected bone regeneration. Animal species, platelet and growth factors concentration, type of bone defect and of platelet concentrate used seemed to influence their efficacy in bone healing. However, sound conclusions were not drawn since too few studies for each large-size animal model were included. In addition, characterization of APCs' content was performed only in a few studies. Further studies with a standardized protocol including characterization of the final products will provide useful information for translating the results to clinical application of APCs in bone surgery.

Efficacy of platelets in bone healing: A systematic review on animal studies.

In presence of large bone defects, delayed bone union, non-union, fractures, and implant surgery, bone reconstruction may be necessary. Different strategies have been employed to enhance bone healing among which the use of autologous platelet concentrates. Due to the high content of platelets and platelet-derived bioactive molecules (e.g., growth factors, antimicrobial peptides), they are promising candidates to increase bone healing. However, a high heterogeneity of both preclinical and clinical studies resulted in contrasting results. Aim of the present systematic review was to evaluate the efficacy of platelet concentrates in animal models of bone regeneration, considering the possible factors which might affect the outcome. An electronic search was performed on MEDLINE and SCOPUS databases. Animal studies with a minimum follow up of 2 weeks and a sample size of five subjects per group, using platelet concentrates for bone regeneration, were included. Articles underwent risk of bias assessment and further quality evaluation was done. Sixty studies performed on six animal species (rat, rabbit, dog, sheep, goat, and mini-pig) were included. The present part of the review considers only studies performed on rats and rabbits (35 articles). The majority of the studies were considered at medium risk of bias. Animal species, healthy models, platelet, growth factors and leukocytes concentration, and type of bone defect seemed to influence the efficacy of platelet concentrates in bone healing. However, final conclusions were not be drawn, since only few included studies evaluated leukocyte, growth factor content, or presence of other bioactive molecules in platelet concentrates. Further studies with a standardized protocol including characterization of the final products will provide useful information for clinical application of platelet concentrates in bone surgery.

Immediate occlusal loading of Osseotite implants in the lower edentulous jaw. A multicenter prospective study.

OBJECTIVE: This paper reports the results of a prospective multicenter clinical study on immediately fully occlusally loaded full-arch screw-retained prostheses with distal extensions (hybrid prostheses) supported by Osseotite implants inserted in edentulous lower jaws. METHOD AND MATERIAL: Sixty-two patients were enrolled in four clinical centers. Three hundred and twenty-five Osseotite implants were inserted and occlusally loaded according to an immediate loading protocol. The temporary prosthesis was delivered 4 h from surgery. The final prosthesis was delivered after 6 months. Marginal bone loss was monitored from periapical radiographs using a computerized technique. RESULTS: Two implants failed to integrate within 2 months of occlusal loading. A cumulative implant success rate of 99.4% was achieved for a period of 12-60 months postplacement (mean 28.6+/-14.1 (SD) months). Crestal bone loss around the immediately loaded implants was similar to that reported for standard delayed loading protocols. CONCLUSION: The results of this study suggest that the rehabilitation of the edentulous mandible by an immediate occlusally loaded hybrid prosthesis supported by five to six Osseotite implants represents a viable alternative treatment to classic delayed loading protocols.