Synthesis Of A Novel Injectable And Water-swelling Gingival Displacement Materials

Gingival retraction technique is widely used in prosthodontics to reduce the damages of periodontal soft tissue during the preparation of abutment and get an accurate impression which is important for optimum marginal adaptation of prosthesis to reach the long-term success. At present, gingival retraction materials mainly include gingival retraction cord and gingival retraction paste. This study was attempted to synthesize a novel injectable, water-swelling gingival displacement materials and evaluated the effect of this materials by animal experiments in dogs.Objective:To synthesize a novel injectable, water-swelling gingival retraction materialsMethod:Polyvinyl pyrrolidone-K90, crosslinked polyvinylpyrrolidone, kaolin and aluminum chloride etc. were mechanically mixed at some certain ratio in water solution, resulting to a novel paste materials for gingival displacement. Then, its stability in aqueous solution and water swelling properties were evaluated in vitro; the effect on gingival displacement was evaluated by animal experiments in dogs. A commercial gingival displacement materials paste of Expasyl (?) was used as control.Results:A paste which showed milkness with viscoelasticity and could mold by injection of a certain pressure were gotten. While the novel gingival displacement paste were stable in water without disintegration, and the water swelling rate was5%after12h in water. When the two materials were immersed in water for8min, the control materials of Expasyl were complete collapsed, while the experimental group were with10%. The SEM photograph showed that the morphological structure were no significant difference in both materials before and after immersing in water. Animal experiments in dogs showed that height of gingival margin and width of gingival sulcus have changed after use both gingival retraction materials. So the synthesized gingival retraction materials could displace the gingival margins from the dental root surfaces with good gingival retraction effect.Conclusion: The novel injectable, water swelling gingival displacement material is efficient to retract free gingival margin with good application prospect.