Dental night guards, otherwise known as mouth guards, are a popular and effective way to deal with teeth grinding and snoring. Unless you plan on spending several hundred dollars to get yourself a custom night guard, you are probably going to be using a boil-and-bite night guard or even generic one-size-fits-all mouth guard.

For those of you suffering from bruxism or sleep apnea, you may be wondering how effective these over-the-counter products are. Can you really get a good night’s rest by using a product that costs less than $100? Unfortunately, as with most products that claim to solve a pressing issue, there are positives and also some negatives. In this article we will be going over the various dental night guard side effects that you may encounter using a boil-and-bite night guard.

Most Common Dental Night Guard Side Effects

People who have used pre-formed, one-size-fits-all mouth guards report that they should only be used to protect your teeth during sports activities, and should not be worn while sleeping since they are bulky and extremely uncomfortable. However, boil-and-bite night guards and custom night guards are legitimate and much more effective products, but unfortunately they have their own share of flaws as well.

General Discomfort

Before even going over what can happen when things go wrong, there are some common complaints that people make when they first start wearing a night guard to sleep every night.

First of all, many people are simply not used to wearing a piece of plastic to sleep every night. Users report that they salivate excessively, to the point where they sometimes drool. They may also find their night guard to be too bulky and have trouble sleeping with a bulky piece of plastic in their mouth.

Next, many users report that they wake up with pain in their teeth and jaw. You should expect an adjustment period of about a week as you get used to wearing a night guard daily. If the pain does not go away, then you may have an improperly fitted night guard and should consider re-boiling it or taking it back to the dentist for those with custom night guards.


If you purchased a dental night guard in stores or online, you may have trouble getting one that fits your teeth well. Pre-formed mouth guards obviously will never fit your teeth perfectly. Boil-and-bite mouth guards require you to boil the mouth guard in simmering water until the plastic softens. Afterwards, you bite into it to create an imprint of your teeth while it is still hot.

Even if you follow the instructions, it can be difficult to get a perfect fit and you may have to do some trial and error. The instructions may ask you to bite into the mouth guard with your lower teeth and jaw slightly forward than usual, for example. Or you may underestimate how hard you are supposed to bite and fail to make a good impression into the plastic. Either way, you may end up with an ill-fitting night guard that slides off your teeth while sleeping or painfully digs into your cheeks.


Dental night guards that are made with gel-like, soft materials are easier to bite into but may get stretched out over time as you grind your teeth. You’ll find that they may not stay on your teeth throughout the night and that would defeat the purpose. Mouth guards made from sturdier materials like acrylic will not have this issue.

Teeth Shifting and Jaw Misalignment

People who have worn braces know that it is possible to shift your teeth over time, and the same is true when it comes to wearing a dental night guard. If you have an ill-fitting night guard and you feel extreme pressure on certain teeth, then it is possible that your teeth are getting shifted. Mouth guards for sleep apnea that tell you to extend your lower teeth/jaw forward to reduce snoring may cause your jaw to be permanently shifted forward.

Irritated Teeth or Gums

Sometimes after boiling a night guard, some of the plastic hardens into an uncomfortable shape that pokes at the inside of your mouth. The affected areas may lead to ulcers. If this occurs, you can cut off the excess plastic or grind it down using a dremel.


In the pursuit of a good night’s sleep, you may consider using a night guard to address your nighttime teeth grinding or sleep apnea. Do not use sports mouth guards or pre-formed mouth guards as they are too bulky and do not fit your teeth very well.

Boil-and-bite night guards as well as custom night guards are the most effective ways to address these issues. Most people will opt for boil-and-bite mouth guards as they are significantly cheaper than a custom night guard. The most pressing dental night guard side effects are the possibility of teeth shifting or jaw misalignment due to improper fitting night guards.

Some general side effects you may experience are sore teeth and jaw, excess saliva, irritation of the inside of your mouth, and ill-fitting night guards sliding off your teeth at night and therefore failing to protect you against snoring or teeth grinding.