Biomimetic Restorative Materials for Soft-Tissue Regeneration in Dentistry

Localised gingival recession is a common problem which is typically corrected by invasive periodontal plastic surgical procedures.  The development of non-invasive management techniques for gingival recession may offer advantages over existing treatment methods.  Incorporation of extra-cellular matrix factors into glass-ionomer cements (GICs) may act as a substrate to enhance cell attachment and ‘creeping’ gingival regeneration.  Therefore the aim of this study was to test the effects of added Gelatin or Bioglass to GICs on mechanical properties and cellular viability and attachment.

Methods:

Gelatin or 45S5 Bioglass(BG) were added to the powder phase of GIC and 4 experimental cements were tested: GIC+1%Gelatin; GIC+5%BG; GIC+1%Gelatin+5%BG; and GIC as a control.  The compressive strength, Young’s modulus, diametral tensile strength and fracture toughness were determined.  Samples were added to PBS and changes in pH and weight measured up to 6 weeks.  Eluents from materials were exposed to human gingival fibroblasts (HGF) for up to 72hrs, and cell viability determined by MTT.  Monolayer experiments with HGF were conducted to evaluate the creeping attachment by measuring cell attachment and migration on blocks over 4 weeks.

Results:

GICs modified with both materials increased fracture toughness, initial pH, cell viability, and increased weight loss over 6 weeks.  Addition of gelatin, but not BG, also decreased compressive strength and modulus of dry specimens (P<0.05).  BG and Gelatin both increased cell attachment and migration of HGF in monolayer experiments, with greatest effect seen with 1%Gelatin+5%BG.

Conclusions:

The fracture toughness of the experimental cements were improved, probably due to the presence of gelatin acting as a matrix.  There were no major deleterious effects on the modulus or strength.  The results clearly indicate that addition of BG and gelatin improves biocompatibility of the GICs.  Creeping attachment of HGF suggests the potential of inducing soft-tissue regeneration of the gingivae.