Actor Mickey Rourke looked unrecognizable in shocking photos captured this week.

“The Wrestler” star, 73, was spotted in LA in a gray hoodie and jeans, but seemed to be missing what could be considered something more important: his teeth.

His dental troubles actually go way back — but an expert explained to The Post how facial trauma and lots of stress have likely contributes to his new look.

Rourke’s face has taken a beating from a young age. He was an amateur boxer as a teen before staring in hit movies in the ’80s — then went back to boxing as a pro in the ’90s.

“He has had some trauma to his face. And that trauma over the years has definitely affected the dental support structures,” said Dr. Jason Auerbach, an oral and maxillofacial surgeon who goes by @bloodytoothguy on social media.

Indeed, Rourke has spoken openly about undergoing a number of facial reconstruction and dental surgeries to correct injuries to his face.

“I had my nose broken twice. I had five operations on my nose and one on a smashed cheekbone,” he told the Daily Mail in 2009. “I had to have cartilage taken from my ear to rebuild my nose.”

To make matters worse, he told the outlet, he “went to the wrong guy to put my face back together” and had to get a number of corrective surgeries.

Rourke also talked about missing teeth back in 2014, telling Jimmy Kimmel that his dentist advised him his implants were 20 years old and might fall out.

Auerbach explained how hits to the face — even if they miss the mouth — can affect the teeth for life.

Take a hit to the jaw, for example. “Oftentimes you fracture not just the area where the direct blow was, but you fracture … the other side,” he explained. “You have significant damage to the support structures of the teeth, which of course then affect the teeth.”

How do you fix something like this? Before reconstruction, the bone needs to provide a solid foundation, and with repeated injuries or just wear and tear, he said, the bone density might just not be good enough.

That means bone grafting has to come first. Doctors can take bone from the hip, lower leg or other parts of the jaw. They might even use bone from a cadaver. After 3 to 6 months, the bone in the face regrows.

After that, screws can be installed into the jaw to provide posts for the fake teeth to sit on.

This is by far the best option to replace teeth, Auerbach said — and though Rourke was told that his implants were going to fall out, this isn’t something most people need to worry about.

“Implants should be seen as basically permanent,” he said. They “should really last a very, very long time, if not a lifetime,” as long as they’re installed by a board certified surgeon, restored by a good dentist, and maintained by the patient.

That said, what makes them “fall out” is real — it’s called bone resorption. Bone is naturally lost around that screw that’s drilled into the jaw in implants over time.

And stress can speed that process up. The stress hormone cortisol decreases calcium absorption, making bones weaker. Stress also increases bone breakdown and slows new bone form being built.

Plus, “the more you clench and grind the teeth, the more bone loss around those teeth that you have, the more wear and tear of the teeth you have. You could fracture teeth,” Auerbach said.

Rourke may be dealing with more than a little of that stress, which could affect his dental health. He was evicted earlier this year from his home.

The actor has talked about taking out his fake front teeth in 2014 for a movie. Auerbach said removable teeth, or dentures, are the most economical but not the best option “in a million ways.”

It’s a pain to take them on and off, keep them clean, and not lose them, which is tough for the elderly. It can make chewing hard, and they put pressure on the gums, he said.

“Imagine having a piece of acrylic or plastic sitting on any mucosa on your in your body that it’s not comfortable. It’s not healthy,” he said. “Long term removable options are a solution when there is no other solution.”