Besides being white and having sharp surfaces, puppy teeth and adult teeth are different in many ways for the simple fact that they were designed for different purposes. As the name implies, puppy teeth are present during puppyhood, and as the puppy grows, adult teeth replace them gradually over the course of several months. Knowing the difference between the two can help you detect early signs of trouble that may require veterinarian attention.
Purpose of Puppy Teeth
Those sharp, needle-like teeth adorning a puppy's mouth have several purposes. From an evolutionary standpoint, pups have sharp teeth to compensate for their lack of strong jaws, and they allow them to tear up the first meat samples the mother dog carried to the den. Those sharp daggers also played a role the weaning process. Vigorous nursing with sharp teeth is painful, even for the most patient of moms. Mom's reluctance to nurse prompts the pups to seek out alternate food sources. Finally, sharp puppy teeth teach rough pups to gauge their bite pressure when playing with their siblings and mom, a fundamental life lesson that will make them safer companions as they mature into dogs with powerful jaws.
Purpose of Adult Teeth
As the dog's jaws become stronger and larger, puppy teeth are no longer adequate, and being brittle as they are, they certainly aren't meant to withstand the wear and tear associated with being a grown up, meat-eating dog. Although less sharp, adult dog teeth are sturdier and built to tear, puncture, chew and grind food into smaller parts that are easy to swallow. Additionally, adult dogs need those teeth for attack and defense purposes. Unlike the more delicate puppy teeth, adult teeth are purposely designed to last a lifetime.
Puppy teeth emerge between the ages of 3 to 6 weeks and are only present for a limited period of time, which is why they're called deciduous. Around 3 months of age the baby teeth start falling out, and around this same time, the first adult, permanent teeth start erupting. During this time, puppies may present with a mix of baby teeth and permanent teeth, but by the time the puppy is 6 months, all permanent teeth should be in place. Monitoring the teething process as the permanent teeth come in is important to ensure no baby teeth are retained, which can cause problems.
Amounts of Teeth
Puppies are granted 28 baby teeth. Because puppies will mostly nurse during their first weeks of life and won't eat much hard food, they won't need to grind much, which explains why they lack molars. They'll need molars, though, later on so they can crush bones. Most adult dogs have 42 teeth comprising two canines, six incisors, eight premolars and four molars in the upper jaw and two canines, six incisors, eight premolars and six molars in the lower one.
Color and Size
Other than having different purposes, emerging at different times and coming in different numbers, puppy teeth and adult teeth look different, too. One of the most evident differences is size. Despite having very long roots compared to the overall size of the tooth, puppy teeth are considerably smaller than permanent teeth. When it comes to color, recently erupted permanent teeth have a brighter white color compared to their precursors.