Metal was utilized in dental work for many years, and only 25 years ago, a dentist would have used such practices readily. However, recent research has shown that such practices can be highly damaging. Mercury and other metals used in this way can severely affect health. They are toxic and can cause oxidative stress and nephrotoxicity; the usage of metal in dentistry has therefore been controversial.
Sleep apnea is a potentially chronic sleep disorder that can harm breathing during sleep. Those afflicted have breathing that starts and stops during sleep, with symptoms such as snoring, feeling fatigued during the day, and waking up during the night with shortness of breath. Sleep apnea does not allow the brain and body to get enough oxygen, which can in turn cause high blood pressure, stroke, heart failure, diabetes, depression, and poor concentration.