Effect of platelet-rich plasma on bone healing of fresh frozen bone allograft in mandibular defects: a histomorphometric study in dogs.

OBJECTIVE: This study histologically analyzed the healing of fresh frozen bone allograft (FFBA) with or without platelet-rich plasma (PRP) in bony defects surgically created in the mandible of dogs. MATERIAL AND METHODS: Bilateral resection defects were surgically created on the inferior border of the mandible in 10 dogs. The defects were randomly divided into three groups: C (the defect was filled by blood clot only), FFBA (the defect was filled with particulate FFBA), and FFBA/PRP (the defect was filled with particulate FFBA combined with PRP). The animals were euthanized at 12 weeks post-surgery. Histomorphometric and histological analyses were performed. Data were statistically analyzed using Friedman test and Dunn test (P < 0.05). RESULTS: Group FFBA/PRP presented a statistically greater mineralized bone area and a smaller marrow bone area than Groups FFBA and C. CONCLUSIONS: The use of PRP improved the incorporation of FFBA, increasing the density of newly formed bone at 12 weeks post-surgery.

Comparison of morphological and functional outcomes of mouse sciatic nerve repair with three biodegradable polymer conduits containing poly(lactic acid).

Poly(lactic acid) (PLA)-containing nerve guidance conduits (NGCs) are currently being investigated for nerve repair as an alternative to autograft, which leads to permanent functional impairment in the territory innervated by the removed nerve. Combination of polymers modifies the physical properties of the conduits, altering their nerve-guidance properties. Conduits made from PLA-only or combined with other polymers have been used successfully for nerve repair, but their efficiency has not been compared. We compared the morphological and functional outcomes of peripheral nerve repair by using NGCs made of poly(lactic acid) and combined or not with polycaprolactone (PLA/PCL) or polyvinylpyrrolidone (PLA/PVP). To assess the functional recovery, we employed a mechanical hyperalgesia analysis, sciatic functional index (SFI), and electroneuromyography. The mechanical hyperalgesia analysis showed that the PLA group improved more rapidly than the PLA/PVP and PLA/PCL groups; similarly, in the electroneuromyography assay, the PLA group exhibited higher amplitude than the PLA/PCL and PLA/PVP groups. However, the SFI improvement rates did not differ among the groups. Morphologically, the PLA group showed more vascularization, while the nerve fiber regeneration did not differ among the groups. In conclusion, the PLA-only conduits were superior to the other NGCs tested for nerve repair.

Long-term therapy with intravenous zoledronate increases the number of nonattached osteoclasts.

The purpose of this study was to investigate the influence of long-term therapy with intravenous zoledronate (ZA) on the healing of extraction sockets in rats. Forty rats, divided into groups C (Control) and Z (Zoledronate), received intravenous injections of either saline solution or ZA for 24 weeks. Their right maxillary incisor was extracted. Euthanasia was performed at 7 or 28 days postoperative. Histomorphometric (Newly Formed Bone Area) and immunohistochemical (RANKL, OPG and TRAP) analyses were performed. Data were statistically analyzed (ANOVA, Tukey's test and Kruskal-Wallis, Dunn's Multiple Comparison test).Groups C and Z showed similar new bone area, RANKL and OPG immunolabeling. The number of TRAP-positive multinucleated cells was significantly higher in Group Z than in Group C at 28 days. A significantly higher proportion of nonattached osteoclasts were seen in Group Z than in Group C at both periods of analysis. Long-term therapy with intravenous ZA stimulated nonattached osteoclast formation in extraction sockets in rats, thus decreasing local bone resorption. However, it did not influence bone formation by osteoblasts.

Platelet-rich plasma derived from bone marrow aspirate promotes new cementum formation.

BACKGROUND: This study evaluates the influence of platelet-rich plasma derived from bone marrow aspirate (PRP-BMA) on the healing of periodontal fenestration defects in rats. METHODS: Periodontal fenestration defects were surgically created in the mandibles of 40 rats. The animals were randomly divided into two groups, control and PRP-BMA, in which defects were filled with blood clot or PRP-bma, respectively. Animals were euthanized at either 10 or 30 days post-surgery. Histologic, histometric, and immunohistochemical analyses were performed. Percentage of new bone area (NBA), area of bone trabeculae (ABT), new cementum (NC), and extension of remaining defect were histometrically evaluated. Proliferating cell nuclear antigen (PCNA), bone sialoprotein (BSP), osteocalcin (OCN), and tartrate-resistant acid phosphatase (TRAP) immunohistochemical staining were performed. Immunolabeled cells were quantified. Data were statistically analyzed (analysis of variance; Tukey, P <0.05). RESULTS: At 10 days, control and PRP-BMA groups presented similar amounts of NBA and ABT; NC formation was not observed. At 30 days, control and PRP-BMA groups presented similar amounts of NBA and ABT; the PRP-BMA group showed NC formation with collagen fibers inserted obliquely or perpendicularly to the root surface. NC formation was not observed in any control group specimen. PRP- BMA presented higher numbers of PCNA-positive and BSP-positive cells than control at 10 and 30 days post-surgery. No significant differences in the number of either OCN-positive or TRAP-positive cells were observed between groups at 10 or 30 days. CONCLUSION: PRP-BMA promoted NC formation with a functional periodontal ligament when applied at experimental periodontal fenestration defects.

Platelet-rich plasma, low-level laser therapy, or their combination promotes periodontal regeneration in fenestration defects: a preliminary in vivo study.

BACKGROUND: This study histomorphometrically analyzes the influence of platelet-rich plasma (PRP), low-level laser therapy (LLLT), or their combination on the healing of periodontal fenestration defects (PFDs) in rats. METHODS: PFDs were surgically created in the mandibles of 80 rats. The animals were randomly divided into four groups: 1) C (control) and 2) PRP, defects were filled with blood clot or PRP, respectively; 3) LLLT and 4) PRP/LLLT, defects received laser irradiation, were filled with blood clot or PRP, respectively, and then irradiated again. Animals were euthanized at either 10 or 30 days post-surgery. Percentage of new bone (NB), density of newly formed bone (DNB), new cementum (NC), and extension of remaining defect (ERD) were histomorphometrically evaluated. Data were statistically analyzed (analysis of variance; Tukey test, P <0.05). RESULTS: At 10 days, group PRP presented ERD significantly lower than group C. At 30 days, group PRP presented NB and DNB significantly greater than group C. Groups LLLT, PRP, and PRP/LLLT showed significant NC formation at 30 days, with collagen fibers inserted obliquely or perpendicularly to the root surface. NC formation was not observed in any group C specimen. CONCLUSIONS: LLLT, PRP, or their combination all promoted NC formation with a functional periodontal ligament. The combination PRP/LLLT did not show additional positive effects compared to the use of either therapy alone.

Bone marrow aspirate combined with low-level laser therapy: a new therapeutic approach to enhance bone healing.

This study evaluated the influence of bone marrow aspirate (BMA), low-level laser therapy (LLLT) and their combination on bone healing in surgically created critical-size defects (CSDs) in rat calvaria. 40 rats were divided into four groups: C (control), BMA, LLLT and BMA/LLLT. A 5mmdiameter CSD was created in the calvarium of each animal. In Group C, the defect was filled by blood clot only. In Group BMA, the defect was filled with BMA. In groups LLLT and BMA/LLLT, the defect received laser irradiation (InGaAlP laser), was filled with blood clot or BMA respectively, and irradiated again. Animals were euthanized 30 days postoperatively. Histomorphometric and immunohistochemical analyses were performed. Newly formed bone area (NFBA) was calculated as percentage of the total area of the original defect. Proliferating cell nuclear antigen (PCNA), runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) immunohistochemical staining were performed. PCNA-positive, Runx2-positive and OCN-positive cells were quantified. Data were statistically analyzed. Group BMA/LLLT had significantly greater NFBA than groups C, BMA or LLLT. Group BMA presented significantly greater NFBA than control, while group LLLT did not. Group BMA/LLLT presented a significantly higher number of PCNA-positive and OCN-positive cells than any of the other groups. Groups BMA/LLLT and BMA showed a significantly lower number of Runx2-positive cells than groups C or LLLT. The combination of BMA/LLLT yielded significantly greater bone formation in surgically created CSD in rat calvaria when compared to control, or either treatment alone.