Is sodium hexametaphosphate effective in preventing metal damage in removable dentures immersed in hypochlorite cleaner

The aim of this study was to evaluate if sodium hexametaphosphate (NaPO3)n is effective in preventing surface changes in Co-Cr-Mo alloy when immersed in cleansing solutions of 0.5% sodium hypochlorite (NaOCl). Thirty samples were randomly divided in to three groups (n=10) according to immersion solution: G1- distilled water (control), G2- 0.5% NaOCl, and G3- 0.5% NaOCl solution containing (NaPO3)n. Samples were evaluated before immersion (T0), 10 minutes (T1), 20 minutes (T2), and 60 minutes after immersion (T3) through Scanning Electron Microscopy (SEM) and rugosimeter. SEM showed little surface alteration in G1, dark stains in G2 and stains suggestive of a thin white film deposition in G3. The roughness analysis showed statistical significance between G1 and G2 (P≤0.05). There was also an increase in roughness in T2 and T3 (P≤0.05). (NaPO3)n protected the alloy from the harmful effects of 0.5% NaOCl, which caused surface alteration and increased roughness.