Colloidal Silver is supposed to have huge positive effects on many ailments. You don't need to be fasting for it to have it's effect and now you've fasted with it.. Have you felt like it helped your fast along at all? If not don't bother with it, the body can take care of itself during a fast and can perform all sorts of miracles without paying a cent for anything to help it along.
Chewing the gum is definitely not good as it adds sugar(or chemical sweeteners!), calories and taste to your fast. Neither are beneficial and is more likely to do harm than good.
Ten days is a respectable fast. Don't worry about what others have done. Your fast will have had benefits of it's own as will any fast, if you get a chance in the future to fast longer it may be of more benefit to you, it depends what you want from a fast too.