The toothed wheels give a slightly better efficiency, but the worm gear is somewhat smoother in its action and entirely silent; the noise of gearing can, however, be considerably reduced by careful machining of the teeth, as is now always done, and also by the use of pinions made of rawhide leather or other non-resonant material.
This is comparable to problems encountered with other chew treats such as rawhide chews, cornstarch bones, pig's ears, and cow hooves.
Rawhide or milk bones are preferable for the same reason.
Most dogs love chewing on rawhide bones.
Keep in mind that rawhide bones contain animal products, so if your dog is allergic to beef or another type of meat, this type of toy might not be a good option for your pet.