Table 1

Summary of the different types of barrier-membranes used for reconstruction of bone defects

Types of membranes


Bioresorbable membranes

Advantages

Disadvantages


Natural membranes

Collagen

(different subtypes, predominantly type-I collagen, derived from different animals, (bovine or porcine) and from different sites (tendon or dermis) [40]

- highly biocompatible (no adverse effect to surrounding tissues during degradation)

- it promotes wound healing [41]

- it allows good integration with connective tissue (fibrous encapsulation with differentiation of a periosteum-like tissue upon the external bony surface) [42,43]

- osteoblasts and fibroblasts can attach to collagen membranes irrespective of its origin [44]

- differently cross-linked collagen membranes can promote cell attachment and proliferation [45]

- degradation in vivo is too rapid to maintain the structural integrity necessary for bone regeneration [44]

- different cross-linking techniques used to prolong degradation time (it varies from four weeks up to six months) [40,41,46]

- differently cross-linked collagen membranes can also inhibit cell attachment and proliferation [45]

- chemicals used for cross-linking have cytotoxic effects on the surrounding tissues leading to gap formation between the membrane and the connective tissue and facilitate microbial accumulation [43] (to address this, a non-chemical cross-linking nanofibrous collagen membrane has been developed) [47]

- variable mechanical properties among the different available membranes

- risk of peri-operative rupture

- moistening of the membrane (unavoidable in vivo) alters considerably the mechanical properties [48]

- possible disease transmission from animals to humans [21,31]


Chitosan or chitosan-collagen hybrid

- non-toxic natural polymer (polysaccharide)

- it enhances wound healing and bone formation [49]

- it has hemostatic properties [50]

- excellent biocompatibility [51], osteogenic cells can proliferate and express osteogenic markers [51]

- chitosan-hybrid membranes have superior mechanical properties [52,53]

- limited evidence from in vivo studies


Synthetic membranes

Aliphatic polyesters: PLLA, PLGA, polydioxanone and their co-polymers [52-54]

- the most commonly used and studied bioabsorbable polymer

- commercially available and approved for clinical use

- by changing the composition and the manufacturing procedure, resorption time, handling properties and mechanical durability can be adjusted to suit the clinical situation [54]

- different chemical compositions did not affect on bone regeneration in vivo [55]

- slow-degrading membranes induce greater amounts of neovascularization and a thinner fibrous capsule versus fast degrading membranes [56]

- they can induce host-tissue response and foreign body reactions during degradation (by non-enzymatic hydrolysis) [13,38,42,57-59]

- the moderate cytotoxic reactions may reduce cellular adhesion [43]


Non-resorbable membranes


Expanded polytetrafuoroethylene (e-PTFE)

And others: titanium reinforced ePTFE, high-density-PTFE, or titanium mesh [23]

- extensively studied [26]

- biocompatible

- they maintain their structural integrity during implantation and have superior space-maintaining properties and capacity for cell occlusion than degradable membranes

- semipermeable ePTFE is more effective than the high-density ePTFE [28]

- for large segmental bone defects, cylindrical titanium mesh cage used as a scaffold [29]

- a second surgical procedure is required for removal (additional potential risk to the newly regenerated tissues [30])

- membrane exposure is frequent, increasing the risk of secondary infection [31,32]

- e-PTFE can induce slight to moderate cytotoxic reactions and reduce cellular adhesion


Novel membranes


Alginate membrane

- close assimilation to bone surface

- no inflammatory response [60]

- easy handling with an alginate base self-setting barrier membrane versus a ready-made membrane [61]

-more efficacious versus collagen membranes for mandibular and tibial defects [62,63]

- limited evidence from in vivo studies


Others [64-68]:

- degradable biopolymer poly (lactide-co-ε-caprolactone)(PLCL),

- a nano-hydroxyapatite/polyamide(nHA/PA66) composite

- an in situ-formed polyethylene-glycol-hydrogel membrane

- amniotic membranes

- a bacterially-derived polymer

- a hybrid membrane consisting of layers of collagen containing hydroxyapatite (HA) and chitosan [69]

- polyethersulfone (PES) electrospun nanofibrous membranes [70]

- a biomimetic tubular calcium phosphate (CaP)-coated nanofiber mesh combined with platelet rich plasma-mediated delivery of BMP-7 [71]

- Latex [72]

- membranes with additional anti-bacterial properties or antimicrobial coating [73-75]

- optimized properties for GBR

- improved three-dimensional structure and osteogenic bioactivity

- they can be loaded with cells to mimic natural bone

- no foreign body inflammatory reaction or rejection and satisfactory bone formation

- membranes with additional anti-bacterial properties or antimicrobial coating may reduce membrane-associated infections


BMP, bone morphogenetic protein;GBR, guided bone regeneration; PLGA, poly(L-lactide-co-glycolide); PLLA, poly(L-lactide).

Dimitriou et al. BMC Medicine 2012 10:81   doi:10.1186/1741-7015-10-81

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