(recommendations are below)
If you haven't tried doing this before, you may assume that your Maltese won't tolerate it; but, you won't know until you give it a chance. For this, be sure to use a paste that is designed for dogs. Human paste is meant to foam, but this can be a choking hazard for dogs (since they will swallow whatever is in their mouth) and often contains fluoride which is toxic to canines.
There are a couple of options in regard to the toothbrush. Ideally, you'll use a 3-sided brush that reaches all three surfaces of the teeth at the same time. However, some dogs need to work up to this. If so, a fingertip-brush (designed to slip over your index finger) can work well.
The most often you brush, the healthier your Maltese's teeth will be. So, aim to make this part of your dog's regular daily care, with a 3 to 5 minute scrubbing each day.
If you choose this option to clean your Maltese's teeth, the
Nylabone Advanced Oral Care Dental Kit

is a set that contains an effective paste, a 3-sided brush, and a finger-tip brush. Note that for most Maltese under 10 lbs. the 'puppy size' option often works best.
2. Or use a dental spray.
This is a good option for dogs that do not tolerate having their teeth brushed and when this is done on a consistent basis, it will remove a good amount of plaque and tartar. As with brushing, using this sort of product regularly will offer the best results.