These muzzles are readily available and used by many veterinary clinics and groomers.  They are not for long term use, and should only be used for quick procedures.  This type of muzzle is designed to fit snuggly and does not allow for panting.

You can also use this technique for training your dog to accept basket muzzles.

Using a styrofoam or paper cup with a treat stuck to the bottom of the cup teaches the dog that sticking its nose in a small area is a good thing. 

You can also feed the dog its meals in this fashion to desensitize them to putting their nose in the cup.

Once the dog is readily putting their nose in the cup it is time to add the muzzle.  The muzzle will be slipped inside the cup with the edges of the muzzle hanging over the edge of the cup.

The cup should be short enough the the dog is able to eat the treats.  If your dog has a short snout, you can cut a styrofoam or paper cup so that your dog's tongue can reach the treats.

The muzzle is not applied to the dog yet.

These pictures show how the muzzle should fit inside the cup.

The next step is to present the cup with treats in the bottom and the muzzle inside the cup.

The dog readily sticks nose in cup that has the muzzle inside.

Slowly raise the strap on the muzzle as the dog continues to eat the treats.  As long as the dog is distracted by the treats you may continue.  The goal is to remove the muzzle and cup before the dog is finished with the treats.

Repeat this process until the strap is applied.

If at any time the dog struggles or backs away, stop and go back to the previous step. 

After you attach the muzzle, remove the cup and continue to feed treats while your dog is wearing the muzzle.

To remove the muzzle, offer the treat filled cup for the dog to stick their nose in.  While the dog is distracted eating the treats, unfasten the muzzle.

During the training process it may be easier to have several cups ready with your dog's meal divided between the cups.  That way, you can move through the process quickly and easily.

Your dog should perceive this process as a fun game.  When your dog looks forward to wearing a muzzle, you know you have trained the procedure well.