Nice to hear from you after such a long time.
I researched this topic thoroughly. I will explain what I have found. The "official" medical list of causes of teeth chattering are: genetic predisposition, neurological disorders and obesity. I will explain these causes in a bit more detail in order to give a better understanding of what may possibly at the root of your problem.
For some reason "being cold" is not listed but perhaps that is because it could be said to fall under "neurological" if one is to explain the process of how it occurs. Our bodies our set up to keep core temperature near 37 degrees Celsius or 99 degrees F. The thermostatic control center in our hypothalamus mediates involuntary muscular contractions and relaxation. Muscular contractions increase heat production, thus increase body temperature.
Factors that disturb or start this process erroneously could result in bodily temperature changes, manifesting as teeth chattering, that might actually indicate an underlying problem with the temperature regulating system of the body. So, checking thyroid function would be an important diagnostic test if a chronic problem is present and no other reason has been identified, especially if other symptoms of thyroid problems are present.
A diseased motor nerve to the muscles of the jaw is another possibility. A Neurologist would be able to examine and test nerve function best. The disorder of neuropathy may be a problem. Neuropathy can effect any nerves of the body but most commonly is found first to effect peripheral nerves such as those in the fingers and toes. Symptoms may be tingling, pin's and needles type pain, and in progressed cases numbness. Neuropathy can decrease the functioning of the nerves as well, so tremors may develop in advanced cases. Neuropathy of the nerves to the jaw muscles could also result in tremors, which would look like teeth chattering.
There are many drugs and other toxins that can effect the nerves and can result in chattering. This includes, among many others, amphetamines, cocaine intoxication, alcohol withdraw, snake venom, arsenic poisoning, SSRI toxicity (antidepressant toxicity).
A disease of the brain, such as Parkinson's, can result in tremors causing chattering along with all the other tremors associated with this disease. Diseases of the cerebellum of the brain can result in chattering. If you had cerebellum disease you might also have balancing problems.
Peripheral Neuropathy most frequently develops in those that have diabetes. Diabetes type II or Diabetes Mellitus occurs most frequently in those who have problems metabolizing sugar and fats. This problem of metabolism occurs more often in those that are obese. Although I did not yet find in the literature how obesity is related to teeth chattering, it could certainly be related by the fact that those with obesity are more likely to develop peripheral neuropathy due to diabetes and high cholesterol than those that are not obese.
Vitamin B12 deficiency can result in teeth chattering as well as other nerve symptoms. Additionally a disorder called cataplexy can result in teeth chattering. Cataplexy could be considered a neurological disorder as it occurs most often in those that have narcolepsy, a disorder associated with insomnia (obesity can result in sleep apnea which can result in insomnia, resulting in narcolepsy, and then often resulting in cataplexy). Cataplexy can occur due to other causes as well. It can be triggered by emotions,. such as anxiety.
We often see chattering associated with high anxiety or fear in television or the movies (example, picture a person with chattering teeth in the horror movie searching for the hidden ghost or killer in the haunted house). To understand more about Cataplexy and how it is related to emotions and teeth chattering, see: http://en.wikipedia.org/wiki/Cataplexy
In your particular case, some of your asthma medications could certainly increase chattering, if not cause it, due to their stimulant effect.. Many people have tremors in the hands after taking any albuterol based medication, so this could result in tremors of the jaw muscles as well.
Due to gentetic you may be more prone to chattering by a dose of medication that does not cause this problem in another person. If you find that anxiety has anything to do with your problem, you will want to learn some anti-anxiety measures, such as slow deep breathing. In fact, anxiety which often causes hyperventilation, increases C02 in the blood stream which can cause numbness in the fingertips and even chest pain, and is also listed as a cause of teeth chattering. While anxious if you start to slow your breathing and to breath deeply this will work to normalize your blood concentration of Co2, thus stopping the teeth chattering as well as help you feel calmer.
I hope you will read over these causes and see if you see any relation to your medications, emotions, sleep, nutritional status (B12 deficiency) etc. This will help you to decide if you need to work on some relaxation exercises, decrease the dose of medication (or at least spread out the dose - of course don't change your medications without speaking to your physician first). Or, if you feel it could be related to an actual problem with the nerves of the jaw, or your cerebellum you will want to see a Neurologist.
Feel free to reply and let me know what your think. Good luck.