Fig. 7
Representative canning electron microscopy images showing the inhibition of E. faecalis biofilms grown on dentin. a–c A biofilm treated with PBS gel for 7 days (a ×5000; b ×25,000; c ×50,000) (negative control). d–f A biofilm treated with 2% chlorhexidine gel for 7 days (d ×5000; e ×20,000; f ×35,000). g–i A biofilm treated with Ag+–Zn2+ gel with 1:12 Ag+–Zn2+ ratio (3.2 × 10−2 mg/mL AgNO3) for 7 days (g ×5000; h ×20,000; i ×35,000). j–l A biofilm treated with gel containing only Ag+ (3.2 × 10−2 mg/mL AgNO3) for 7 days (j ×5000; k ×20,000; l ×50,000). m–o Biofilm treated with gel containing only Zn2+ [67.2 × 10−2 mg/mL Zn(NO3)2·6H2O] for 7 days (m ×5,000; n ×20,000; o ×25,000)