There are many oral conditions and complications that take place when patients are using many drugs.
A good website to use to research out medications is www.drugstore.com. They have a section where you can check out common side effects of medication you or someone you know may be on. It also has a section that will list drug interactions if you are on multiple medications.
As I have discussed in the past, the most common side effect of medications is a drying of the mouth. The biggest mistake I see patients who have a dry mouth is to suck on mints, candies, chocolates, or sodas sweetened with natural sugar. When sucking on the candies, they coat the teeth with sugar which in turn develops into a full blown case of dental decay. Patients are shocked when I show them the destruction that these cause. Sugar-free AquaDrops candies are a great way to stimulate saliva while not creating multiple cavities in the mouth. You can find these in just about any pharmacy.
A good toothpaste that will help the balance in the mouth is Crest Pro-health or Biotene toothpaste. They contains anti-fungal and anti-bacterial agents in this specially formulated toothpaste. For dry mouth it was recommended to use Biotene oral balance gel. This is also available over the counter. When using this gel first swish with water, then use a small glob and move it around to lubricate the mouth. It has been reported to cool a dry mouth and make it feel much better.