Adsorption and release kinetics of growth factors on barrier membranes for guided tissue/bone regeneration: A systematic review

OBJECTIVES

Guided bone / tissue regeneration (GBR/GTR) procedures are necessary to improve conditions for implant placement. These techniques in turn can be enhanced by using growth factors (GFs) such as bone morphogenetic protein (BMP-2) and platelet-derived growth factor (PDGF) to accelerate regeneration. The aim of the present systematic review was to evaluate the GF loading and release kinetics of barrier membranes.

STUDY DESIGN

A total of 138 articles were screened in PubMed databases, and 31 meeting the inclusion criteria were included in the present systematic review.

RESULTS

All the articles evaluated bio-resorbable membranes, especially collagen or polymer-based membranes. In most studies, the retention and release kinetics of osteogenic GFs such as BMP-2 and PDGF were widely investigated. Growth factors were incorporated to the membranes by soaking and incubating the membranes in GF solution, followed by lyophilization, or mixing in the polymers before evaporation. Adsorption onto the membranes depended upon the membrane materials and additional reagents such as heparin, cross-linkers and GF concentration. Interestingly, most studies showed two phases of GF release from the membranes: a first phase comprising a burst release (about 1 day), followed by a second phase characterized by slower release. Furthermore, all the studies demonstrated the controlled release of sufficient concentrations of GFs from the membranes for bioactivities.

CONCLUSIONS

The adsorption and release kinetics varied among the different materials, forms and GFs. The combination of membrane materials, GFs and manufacturing methods should be considered for optimizing GBR/GTR procedures.

A Clinical Evaluation of Biphasic Calcium Phosphate Alloplast with and without a Flowable Bioabsorbable Guided Tissue Regeneration Barrier in the Treatment of Mandibular Molar Class II Furcation Defects

BACKGROUND

Guided tissue regeneration (GTR) therapy has shown good results in the management of mandibular molar class II furcation defects. Advances in biomaterial sciences have developed alloplastic bone replacement graft materials and bioabsorbable GTR barrier membranes with good biologic response and handling properties. The aim of this study was to compare the attachment gain and the bone fill obtained with an alloplast [biphasic calcium phosphate (BCP) 60% hydroxyapatite (HA) and 40% beta tricalcium phosphate (b-TCP)] with and without a bioabsorbable GTR barrier [flowable poly (DL-lactide) (PLA) dissolved in N-methyl-2-pyrrolidone (NMP)] in the treatment of mandibular molar class II furcation defects.

MATERIALS AND METHODS

A total of 20 class II furcation defects were treated in 16 patients with chronic periodontitis in a comparative study. Ten defects were treated with Camceram(®) (BCP 60% HA and 40% - TCP) bone replacement graft material (group I) and 10 defects with a combination of Camceram® bone replacement graft material with Atrisorb® Freeflow™, bio-absorbable GTR barrier (flowable PLA dissolved in NMP) (group II). At baseline and at 6 months postsurgery, clinical parameters of vertical probing depth (PD) and horizontal probing depth (P-H), clinical attachment level (CAL), gingival recession (GR), and vertical depth of furcation defect (VDF) and horizontal depth of furcation defect (BP-H) were evaluated.

RESULTS

Statistical analysis was done with the Statistical Package for Social Sciences (SPSS) program. Intergroup comparisons made at 6 months postsurgery by unpaired Student's t-test showed mean reduction in PD in group I was 3.10 ± 0.73 mm and in group II was 3.20 ± 1.03 mm (p > 0.05). Mean reduction in P-H in group I was 1.60 ± 0.69 mm and in group II was 1.90 ± 0.73 mm (p > 0.05). Gain in CAL in group I was 2.80 ± 1.03 mm and in group II was 2.90 ± 0.94 mm (p > 0.05). Change in GR in group I was -0.30 ± 0.48 mm and in group II was -0.30 ± 0.48 (p > 0.05). Reduction in VDF in group I was 1.30 ± 0.67 mm and in group II was 1.80 ± 0.63 mm (p ≤ 0.01). Reduction in BP-H in group I was 1.30 ± 0.67 mm and in group II was 1.90 ± 0.73 mm (p ≤ 0.05).

CONCLUSION

It was concluded that the combination technique of BCP alloplast with a flowable bioabsorbable GTR barrier led to better results in regard to defect bone fill as compared with when the BCP alloplast alone was used.