Martial Arts Stack Exchange is a question and answer site for students and teachers of all martial arts. It only takes a minute to sign up.
Sign up to join this community
In just trying things out, I have put a knife in my teeth and clamped down while doing something with my hands and then picked the knife up again. I found no matter how easily they do it in the movies, it really freaking hurts the teeth and seems a completely silly and unrealistic approach to keep a knife handy while using your hands to climb something.
Is there an actual way to do this without hurting your teeth, or is it just a Hollywood thing that looks cool but is completely unrealistic?
To answer your question as stated; While, it is possible to carry a knife in your teeth without injury there is no method by which you can do it safely.
The teeth are formed in such a way that they are remarkably strong and resilient to damage (reference). However they are also fairly fragile due to the brittle nature of glass-like dentin. Especially when they develop micro-fractures from long term damage from things such as impacts, biting hard foods (i.e. ice, nuts, popcorn kernels), and misuse. Misuse can be anything from biting open packages to opening beer bottles to carrying your pirate cutlass in your teeth!
This mainly falls under the "Rule of Cool" and is specifically referenced here at tvtropes.org. Ultimately, though others may have been a bit harsh in their response, they were correct in that it is never advisable to put a hard object in your mouth. Especially while doing vigorous physical activity like climbing wet ropes in rough seas or fighting pirates! Leave it to the actors to look cool doing stupid things, and spend your time training the fundamentals of whatever martial art you practice... because it's the fundamentals that save your butt in a pinch.
So you've tested it, and found it lacking.
But are you going to believe HOLLYWOOD FRICKING MOVIES, or your own lying experience?
It is more a matter of "how" and "what knife".
https://www.thestar.com/news/crime/2011/02/01/woman_held_knife_in_her_teeth_murder_trial_told.html
She got it to work for her. Well, sort of, she's on trial.
In that case she was (allegedly) holding the knife with the handle in her mouth, sticking straight out.
I would say that if your stationary and just want to get it out of your hand for a couple seconds while you do something that requires both hands, it might be doable.
If you're climbing a soaking wet rope ladder hanging off the side of a ship in heavy seas, at night, expecting to find a fight at the rail? Might want to give that one another think.
So while it's possible with the right knife and the right situation, I wouldn't want to rely on it, and wouldn't train it.
