ABSTRACT
Gingival retraction is essential to get a dry and debris free field, which enables the impression material to flow into the gingival sulcus and record the area apical to the finish line. Effective gingival retraction without damaging periodontal tissue is extremely important. Objective: To comparatively evaluate the amount of inflammation, as assessed by TNF-α in GCF induced by three different gingival retraction techniques. Methods: Ten patients with a minimum of three teeth that required biomechanical preparation for fixed prostheses and acceptable oral hygiene with no periodontal pathology were included. The patients each received an oral prophylaxis. After a washout period of 10 days patients with gingival index scores of 0 or 1 were included. Measurements of TNF-α was done at baseline, after 30 min, after 7 days and after 28 days using ELISA test kit specific to TNF-α. Results: The sample population for whom Magic Foam cord was used showed a massive reduction in the amount of TNF -α, from 78% at 7 days to 18.6% at 28 days. There was a reduction in the percentage of TNF -α produced in the samples where normal knitted cord was used and for those where Expasyl was used from 95% to 64.2% and from 70% to 48.3% respectively. Conclusion: Maximum amount of inflammatory response was seen with plain knitted gingival retraction cord. This was followed by Expasyl gingival retraction system and the least amount of inflammatory cytokine was recorded with Magic Foam retraction cord.
ABSTRACT
PURPOSE: To evaluate the physical and mechanical properties of maxillofacial silicone elastomers following the incorporation of a specific particle size and concentration of nano-titanium dioxide (TiO2) and nano-zinc oxide (ZnO). MATERIALS AND METHODS: Nano-TiO2 and nano-ZnO of 20-nm and 40-nm particle sizes and in 1% and 2% concentrations were chosen. Silicone elastomer samples were prepared according to the manufacturer's recommendations. The nano-oxides were incorporated via hand spatulation. The samples were subsequently tested for hardness and color stability and were then subjected to aging in an aging chamber for 1,008 hours, following which they were again evaluated for hardness, color stability, and surface roughness. RESULTS: A significant change was noted in the physical and mechanical properties post-aging in all the groups. The samples with nano-TiO2 of 40-nm particle size/2% concentration had the highest hardness, while color stability and surface roughness were higher in samples with nano-TiO2 of 20-nm particle size/1% and 2% concentrations, respectively. CONCLUSION: It can be concluded that 20-nm nano-TiO2 particles best maintain the ideal properties of maxillofacial silicone elastomers and can potentially be used as alternative opacifiers when mixed with A-2186 maxillofacial silicone elastomers.