Why do most MMA and Muay Thai fighters not wear Double Mouth Guards on both teeth, both top side and bottom side? They say having a mouthguard on top side with mouth clenched, will prevent damage on bottom. However, it seems like a front teep kick to bottom of head, or a clenched position with knee will cause damage to bottom teeth. Even a slight disruption, pain, or air gasp will make the mouth slightly open, which can cause an issue. It's just amazing that professional fighters do this. If anyone can explain, that would be helpful.

Not sure if UFC professionals just would rather risk bottom teeth damage, because I know double side mouth guards are harder to breathe in also.

I am sparring in Muay Thai, and curious about this.

2 Answers 2


The primary reason for mouth-guards is to guard against the damage that happens when they teeth crash into each other. For that reason, a single-mouth guard is generally sufficient, providing a guard between uppers and lowers. So why not get that little bit more protection? As you note, they are harder to breathe in. A major factor in most professional fighting is oxygen and fuel reserves. Fights often come down to superior conditioning as one fighter or the other gets sloppy due to fatigue. The restriction of breathing caused by a double mouth guard is a hindrance to performance, and while every fighter would prefer to get out of their matches with teeth entirely intact, one of their primary concerns is winning, so they can't afford to take that performance hit for a minor benefit.

  • are you saying that most damage from teeth come from your actual Own teeth crashing together, and not the collision of the punch/or leg kick hitting the teeth? interesting
    – mattsmith5
    Commented Dec 8, 2021 at 21:02
  • I don't have the data onhand to prove it, but that's what I was taught, that teeth typically fracture from hitting hard surfaces. Outside of combat, that usually involves falling against the hard object such as the classic chipped teeth from falling into stairwells, or diving into shallow water and hitting the bottom. In a combat scenario where the face is not being forcefully introduced to surfaces, the closest hard surfaces are the other teeth. I have a vague feeling that the use of mouthguards is also because loose teeth can be set back in place, while broken teeth need to be rebuilt. Commented Dec 8, 2021 at 21:22
  • There's a bit of data here about the history of mouthguards and how they work, including data on how double mouthguards roughly double the difficulty of breathing over single. Commented Dec 8, 2021 at 21:23

The conventional mouth guard cups the upper mouth so the lower jaw can "Sink" into it.enter image description here This serves to....

  1. protect jaw bone from lateral strikes
  2. Cushion teeth shattering against hits
  3. prevent fighter from biting tongue don't think they serve to protect your teeth against forward strikes
  • hi, what is the last picture about? it seems like they are using mouth guard and still got damage
    – mattsmith5
    Commented Dec 13, 2021 at 2:42
  • @mattsmith5: Yes, that was a case where the mouthguard failed although I don't know the details behind it. Commented Dec 13, 2021 at 4:16
  • The image might make sense with context, such as establishing that this damage happened, e.g., because the mouth guard wasn't properly fitted, or that it was an injury that would have been protected against with a double mouth-guard. Commented Dec 13, 2021 at 21:49

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