Mercury mangles S mutans

I've spent the morning chauffeuring my aging mother to her dentist for two root canals. If we, as my hygienist told me, tend to outlive our teeth, here's a bit of good news about those supposedly toxic mercury fillings that abound in aging mouths such as mine.

German researchers counted the cavity-causing Streptococcus mutans clinging to various surfaces artificially inserted in mouths. There are far fewer bacteria carrying on their daily lives on the old black fillings then on the attractive teeth-colored composite ones. As metallic ions in such stuff as mercury amalgam or gold are toxic to these bacterial bad boys, old fillings are a less congenial climate for creeping decay.

The German dentists did note that:

1. This does not "dilute the controversy" over mercury toxicity.
2. Frequently brushing one's teeth still remains the most important preventive measure in dental health.
3. Mercury-laden amalgam remains a viable option for restorative work.