Table 2 Representative free text participant comments.

Gumshields must be [made] to a certain quality as some boil and bite gumshields are shocking. I think it should [be] mandatory to wear custom fit dentist [-made ones] for anyone doing headshots … but all children should wear them (boil and bite ones at least) when competing, even when no headshots, just for safety in case of an accidental head shot. [Male, age 25–29, advanced skill level]

I got mine from an online business that sends a mould to your door, and you mould it yourself. It fits well and doesn’t move during blunt trauma. The boil and bite ones have always left me with cut gums due to the movement of the material over the gum line. [Male, age 18–24, advanced skill level]

I have always wanted to get a [custom] fitted gum guard. However, I have a semi-permanent retainer and have not wanted the expense to have the retainer removed. [Male, age 18–24, advanced skill level]

I tend to lose things as small as mouth guards quite easily. I wouldn’t mind paying £60 for a properly fitted mouth guard that would last 2 years, but if I lost that one (quite likely within 2 years) I would just replace it with a cheap one. [Female, age 25–29, beginner skill level]

I have, and have always had, the terribly bad habit of not wearing a mouth guard during sparring, despite knowing full well what risks this presents. This [is] usually down to the discomfort felt by low cost bite and boil mouth guards - but I should definitely invest in a [custom] fit [mouth] guard! [Male, age 25–29, advanced skill level]

I have had a number of mouth guards over the years, for Muay Thai as well as other sports such as American football and after getting a professionally fitted mouth guard from a dentist, I will never purchase a boil to fit mouth guard again. They are 100 times better. [Male, age 18–24, advanced skill level]

My mouth guard was made by a company not necessarily a dentist … was an easy way through the internet where you do the mould yourself and send it off. Best I’ve ever had. If your mouth guard is fitted on top and doesn’t fall down and you can speak clearly, I’ve noticed a massive difference. [Female, age 25–29, professional skill level]

I’ve never fully looked into whether there are any downsides to mouth guards, but from playing contact sports at school, going into boxing and then Muay Thai, it’s always been seen as standard practice. Whenever possible (i.e. when I have been able to afford to), I have gone for a mould mouth guard as I find it far more comfortable to wear and easier to communicate and breathe when wearing. [Male, age 30–34, advanced skill level]