Amalgam filling (Mercury)
I can’t find consistence information, so: Does a mother need to stop breastfeeding a small baby for the removal of 1 amalgam filling?
Have you seen the comprehensive discussion on the NHS Specialist Pharmacy Service https://www.sps.nhs.uk/articles/is-it-safe-to-have-amalgam-fillings-placed-or-removed-if-breastfeeding/ (download the pdf) it includes a useful summary and many references. There is also some information on e-lactancia (a Spanish medication site) that may be helpful http://www.e-lactancia.org/sinonimo/401
Another resource to check is the Breastfeeding Network’s Information Sheet on Dental Treatment and Breastfeeding Mothers updated 2017 https://breastfeedingnetwork.org.uk/wp-content/dibm/dental%20treatment%20and%20breastfeeding.pdf
Fillings – there is no reason to avoid inserting or replacing fillings during breastfeeding.
One report suggests that it is prudent to avoid unnecessary removal of fillings during pregnancy or lactation (Barreguard 1995). However there are occasions when a new mother may need a filling inserted or replaced. When mercury is removed some will be vaporised by the high-speed drill and a very small amount may be swallowed or inhaled. These amounts are minute and passage into breastmilk is insignificant compared to the background levels of mercury in the environment.
Thomas Hale in Medications and Mothers’ Milk Online, 2017 http://www.medsmilk.com suggests a dentist can take precautions when removing the filling to minimise exposure to the amalgam such as:
use copious amounts of cold water irrigation to minimize heat, use a rubber dam to isolate [the mother’s] mouth from the particles, and use an alternate source of air (oxygen) to minimize mercury vapor inhalation during removal of the amalgam.
I hope that helps!