Working Your Way Up
Having the right supplies is important; you'll want to put a bit of time into choosing the best toothpaste and toothbrush for your Shih Tzu. Be sure to use canine toothpaste. Using human toothpaste can be less than effective at best and poisonous at worst. Once your dog is trained to sit still while you touch their teeth, you can then add some canine tooth paste onto your finger and rub it on their teeth. This will allow your Shih Tzu to become used to the taste and feel of the paste.
The next step will be to raise the level of cleaning by using a finger brush; this can be found at quality dog supply stores or online stores. Add some of the dog toothpaste onto the brush and run it over all of your Shih Tzu's teeth.
The final step will be to use a high quality dog tooth brush and give your Shih Tzu a complete and thorough cleaning. This should be done once per day. Generally any type of grooming works best if you set up a certain time of the day to perform it. This breed is very intelligent; they will be accustomed to this daily burst of flavor in their mouth!
In addition to the daily brushing, there are dental rinses that can be added to your dog's water that will help as well. Keep in mind, your goal is not to address cavities; dogs rarely will have a cavity. It is the plaque and tarter that will do the damage.
Taking care of your Shih Tzu's teeth will allow your dog to live longer and enjoy their senior years, eliminating the possibility of painful and deadly infections.