The Thumbnail Test: Is This Chew Safe for Your Puppy?

Teething puppy tips often start with chew safety, because tender puppy teeth can crack on the wrong chew. The thumbnail test takes five seconds and tells you whether a chew is too hard. Veterinary dentists have a simple rule behind it: don’t let your dog chew anything that won’t bend.

What are the thumbnail test and the knee test?

For the thumbnail test, press your thumbnail into the chew. A safe chew should dent. If your nail makes no mark at all, the chew is likely too hard for tender teeth. Soft rubber teething toys bend and dent, so they pass.

For the knee test, ask whether you would hit the chew against your own kneecap. If you wouldn’t, it is too hard for your puppy’s teeth. Use it as a second check on anything that passes the thumbnail test but still feels like wood, stone or bone.

How to use the tests, step by step

1. Press. Push your thumbnail into the chew and look for a dent.
2. Knee test. Ask yourself if you would hit it against your kneecap.
3. Check the size. A chew must be too big to fit fully in your puppy’s mouth.
4. Supervise. Stay close while your puppy chews and replace damaged toys.

Which chews usually fail?

The big back teeth, called carnassials, break most often on hard chews. If a chew in your home fails either test, bin it or put it out of reach, and swap in a soft rubber toy. Items to skip include:

• Antlers and hooves
• Cooked or raw bones
• Hard nylon bones
• Ice cubes and rocks

VCA also lists rawhide, pig ears, bully sticks and tennis balls for choking or blockage risk. Do not use clove oil, human teething gels or human pain medicine either.

Which chews usually pass?

Passes the tests	Notes
Soft rubber puppy toys	Stuff and freeze them for sore gums
Rope toys	Supervise and trim loose threads
Soft plush toys	Check seams and replace when damaged
Frozen knotted washcloth	Remove it if threads come loose
Puppy teething rings	Check the size rule

No toy is 100 percent safe, so supervision matters more than the label. If a toy cracks, shreds or gets small enough to swallow, take it away.

How does cold help sore gums?

Cold soothes sore gums. Serve frozen food inside a rubber toy or on a lick mat, never as a hard frozen block, and let it sit for 5 minutes so it softens slightly. Count treats as part of the day’s food.

The same tests apply to cold chews. A cold carrot is chilled for 2 hours, or frozen for just 30 minutes, so it is cold but still has some give. Hold one end at first so your puppy gnaws, take it away once it is small enough to swallow, and give no more than one carrot a day.

Will the right chew stop puppy biting?

Teething drives chewing on objects, while biting people is mostly play. A safe chew gives sore gums something to do, but it will not fix hand biting on its own. For the calm response to teeth on skin, read the 5-step method.

Run the thumbnail test on every chew in your home today and bin anything that fails. If your puppy swallows pieces or shows signs of a broken tooth, use the help box below.