Effect of Bio-OssR with or without platelet-derived growth factor on bone formation by "guided tissue regeneration": a pilot study in rats

The effects of autologous platelet concentrate on the healing of intra-bony defects: a randomized clinical trial

PURPOSE

The present study aimed to evaluate the clinical and radiographic effects of autologous platelet concentrate (APC) on the healing of intra-bony defects filled with β-tricalcium phosphate (β-TCP) and covered with collagen membranes.

SUBJECTS AND METHODS

This study included 30 defects of 14 systemically healthy subjects. All of them had, at least, two deep intra-bony, inter-proximal periodontal defects. Minimum probing pocket depth (PPD) was 6 mm. Clinical and imaging examination was performed both at baseline and at 3, 6, and 9 months after surgery.

RESULTS

Both the test and control group revealed a significant reduction in all variables when compared with the base line. Mean reduction of the PPD in two groups at each follow-up time point showed no significant difference. Means of the clinical attachment gain of the same groups were significantly different (p<0.05). Mean gingival recession at 3 month was not significant. However, the means of gingival recession coverage of two groups were significantly different at 6 and 9 months (p<0.05 for both).

CONCLUSION

Sites treated with APC are more likely to demonstrate more clinical attachment gain and recession coverage at the end of 9 month compared to those without APC.

Effect of recombinant PDGF-BB on bone formation in the presence of β-tricalcium phosphate and bovine bone mineral matrix: a pilot study in rat calvarial defects

Background

Supplementation of bone substitutes with recombinant platelet-derived growth factor-BB (PDGF-BB) can enhance bone regeneration. The aim of the study was to evaluate the effect of PDGF-BB on bone formation in the presence of β-tricalcium phosphate and bovine bone mineral matrix in a rat calvaria defect model.

Methods

The authors examined 5 mm rat calvarial defects treated with β-tricalcium phosphate (TCP) or demineralized bovine bone mineral (DBBM) with and without 0.3 mg/ml recombinant PDGF-BB. Calvaria defects were randomly divided into the following treatment groups (n = 5); TCP; TCP plus PDGF-BB; DBBM; DBBM plus PDGF-BB; and untreated empty control. After 45 days, bone formation was evaluated by histomorphometry and fluorescence microscopy.

Results

The authors report that the area of newly formed bone was similar between the empty controls and the two bone substitutes, TCP and DBBM. Supplementation of TCP and DBBM with PDGF-BB had no significant impact on bone formation. Fluorochrome staining revealed no visible changes in the pattern of bone formation in defects filled with TCP and DBBM, irrespective of PDGF-BB. Furthermore, supplementation with PDGF-BB did not influence biomaterial degradation.

Conclusions

The authors concluded that PDGF-BB had no impact on bone formation and degradation of bone substitutes in the respective rodent models. Thus, possible beneficial effects of PDGF-BB may require other model situations.

Comparison of tissue-engineered bone from different stem cell sources for maxillary sinus floor augmentation: a study in a canine model

PURPOSE

To compare the potential of tissue-engineered bone derived from different stem cell sources for canine maxillary sinus augmentation.

MATERIALS AND METHODS

Bilateral maxillary sinus floor augmentations were performed in 6 beagles and were randomly repaired with 3 graft types: Bio-Oss granules alone (n = 4; group A), a complex of osteoblasts derived from bone marrow mesenchymal stem cells (BMMSCs) and Bio-Oss (n = 4; group B), and a complex of osteoblasts derived from periodontal ligament stem cells (PDLSCs) and Bio-Oss (n = 4; group C). After 12 weeks, fluorescent labeling, maxillofacial computed tomography, scanning electron microscopy, and histologic and histomorphometric analyses were used to evaluate new bone deposition, mineralization, and remodeling in the augmented area.

RESULTS

The osteogenic capacity was greater in groups B and C than in group A. The level tended to be higher in group C than in group B; however, the difference was not statistically significant.

CONCLUSIONS

Seeding of PDLSCs or BMMSCs onto Bio-Oss can promote bone formation and mineralization and maintain the maximum volume of the augmented maxillary sinus. These tissue-engineered bone complexes might be a good option for augmentation of the maxillary sinus in edentulous patients.

Significance of the platelet-derived growth factor in periodontal tissue regeneration

AIM

The aim was to review the significance of the platelet derived growth factor (PGDF) in periodontal tissue regeneration.

METHODS AND RESULTS

Databases were searched using the following terms in different combinations: "growth factors", "guided bone regeneration", "guided tissue regeneration", "periodontal", "platelet rich plasma" and "platelet derived growth factor". Titles and abstracts of articles obtained using the above-described criteria were then screened by the authors and checked for agreement. The next step was to hand-search the reference lists of original and review studies that were found to be relevant in the previous step. PDGF has a stimulatory effect on the DNA replication and chemotaxis of osteoblasts, fibroblasts, leukocytes, monocytes, neutrophils periodontal and alveolar bone cells. Proliferation of mesenchymal stem cells is also promoted by supplement treatment with PDGF. PDGF in combination with other growth factors enhances periodontal tissue repair.

CONCLUSIONS

The PDGF plays a significant role in periodontal bone and tissue regeneration.

Evaluation of early healing events around mesenchymal stem cell-seeded collagen-glycosaminoglycan scaffold. An experimental study in Wistar rats

PURPOSE

Tissue engineering using cell-seeded biodegradable scaffolds offers a new bone regenerative approach that might circumvent many of the limitations of current therapeutic modalities. The aim of this experiment was to study the early healing events around mesenchymal stem cell-seeded collagen-glycosaminoglycan scaffolds.

METHODS

The 5-mm critical size defects were created in the calvarial bones of 41 Wistar rats. The defects were either left empty to serve as controls (n = 11), filled with cell-free scaffolds (n = 12), cell-seeded scaffolds that were maintained in standard culture medium (n = 9), or cell-seeded scaffolds that were maintained in osteoinductive factor-supplemented medium (n = 9). The animals were sacrificed at 7 days after surgery, and specimens were prepared for histological analysis. Early healing events such as host cell penetration, blood vessel in-growth, and scaffold integration were observed. The degree of inflammatory cell infiltrate was assessed.

RESULTS

While defects in the control group healed with a thin fibrous tissue, the collagen-glycosaminoglycan scaffold in the test groups preserved the three-dimensional form of the defects. After 7 days in vivo, the scaffold maintained its integrity and appeared populated with host cells. The cell-seeded scaffold induced more inflammatory response compared to the cell-free scaffolds. New blood vessels and areas of early bone formation were also evident in the cell-seeded scaffolds.

CONCLUSIONS

In conclusion, the findings show that mesenchymal stem cell-seeded collagen-glycosaminoglycan scaffolds have good tissue tolerance and exhibit an osteoinductive effect as indicated by early stage healing.

Pre-clinical models for oral and periodontal reconstructive therapies

The development of new medical formulations (NMF) for reconstructive therapies has considerably improved the available treatment options for individuals requiring periodontal repair or oral implant rehabilitation. Progress in tissue engineering and regenerative medicine modalities strongly depends on validated pre-clinical research. Pre-clinical testing has contributed to the recent approval of NMF such as GEM 21S and INFUSE bone grafts for periodontal and oral regenerative therapies. However, the selection of a suitable pre-clinical model for evaluation of the safety and efficacy of a NMF remains a challenge. This review is designed to serve as a primer to choose the appropriate pre-clinical models for the evaluation of NMF in situations requiring periodontal or oral reconstruction. Here, we summarize commonly used pre-clinical models and provide examples of screening and functional studies of NMF that can be translated into clinical use.

Assessment of the potential of growth factors for localized alveolar ridge augmentation: a systematic review

OBJECTIVE

To systematically assess the literature regarding the clinical, histological, and radiographic outcome of bone morphogenetic proteins (BMP-2, BMP-7), growth/differentiation factor-5 (GDF-5), platelet-derived growth factor (PDGF), and parathyroid hormone (PTH) for localized alveolar ridge augmentation.

MATERIAL AND METHODS

Five separate Medline searches were performed in duplicate for human and animal studies, respectively. The primary outcome of the included studies was bone regeneration of localized alveolar ridge defects or craniofacial defects.

RESULTS

In six human studies, BMP-2 affected local bone augmentation with increasing volume for higher doses. A majority (43 of 45) of animal studies using BMP-2 showed a positive effect in favour of the growth factor (GF). In six of eight studies, a positive effect was associated with the use of BMP-7. Only one animal study was included for GDF-5 revealing statistically significantly higher bone volume. Regarding PDGF, statistically significantly higher bone volume was observed in five of 10 included studies. Four animal studies using PTH revealed statistically significantly more bone regeneration compared with controls.

CONCLUSIONS

Differing levels and quantity of evidence were noted to be available for the GFs evaluated, revealing that BMP-2, BMP-7, GDF-5, PDGF, and PTH may stimulate local bone augmentation to various degrees. Human data for the potential of rhBMP-2 are supportive.

Calcium alginate film used for guided bone regeneration in mandible defects in a rabbit model

The objective of this research was to study a new bioabsorbable membrane material, calcium alginate film (CAF), used for guided tissue regeneration (GTR) or guided bone regeneration (GBRL). Circular bone defects of five mm diameter were created in the corners of the mandibles in 45 rabbits. The defects covered with calcium alginate film (CAF) served as the experimental sites, and collagen membrane (CM) or no membrane served as the control sites without considering left or right side, just with a mark on the ear of the same side. The healing condition was analyzed by histological studies and histometry analysis after one, two, four, six, and eight weeks. The histological evaluation showed that the bone regeneration pattern was centripetal in growth from the defect rim. The quantitative histometry analysis showed significantly more and faster newly generated bone in CAF defects than that in CM defects or in empty defects (p < 0.01) at two, four, six, and eight weeks postsurgically. Calcium alginate film was more effective for GTR and GBR than the collagen membrane.

Sinus floor elevation using autogenous bone or bone substitute combined with platelet-rich plasma

OBJECTIVE

Sinus augmentation is a common approach for patients with severe alveolar ridge atrophy. However, autogenous bone sometimes results in donor site complications. Bone substitutes with platelet-rich plasma (PRP) promote early bone formation with autogenous bone. Use of PRP on autogenous bone and a bovine bone substitute were investigated in this split-mouth animal study.

STUDY DESIGN

Premolars were extracted from minipigs. Each animal received sinus augmentation using a lateral approach with simultaneous insertion of 3 implants in each site. Groups were randomized using autogenous bone alone and combined with PRP or a bovine hydroxyapatite alone in combination with PRP.

RESULTS

Microradiographic findings in the autogenous group did not show significantly different rates by using autogenous bone alone or combined with PRP. Using the bovine hydroxyapatite as augmentation material only at 8 weeks, a nonsignificant effect in the PRP group could be seen. At all other observation periods, no significant influence was observed.

CONCLUSION

No significant influence of PRP was found.

Application of a new bioresorbable film to guided bone regeneration in tibia defect model of the rabbits

Aim is to study the effect of calcium alginate film (CAF) on guided bone regeneration (GBR). Circular bone defects with 5 mm diameter were created in both tibias in 60 rabbits. The defects covered with CAF served as the experimental site, and with collagen membrane (CM) or with no membrane both served as the control site. Healing was analyzed by gross, X-ray, electromicroscopy, histology, immuno-histochemical studies, and an image pattern analysis system after 1, 2, 4, 6, and 8 weeks. The CM control sites showed more macrophages, and CM were absorbed more slowly while collecting fewer osteoinductive factors (p < 0.01) in the early weeks. CAF induced dense bone formation, whereas CM induced less new bone, and the blank control sites effected the worst. In conclusion, the effect of CAF group gave better results than blank control group and CM group on GBR in this animal model.