Most of us don’t even think to look in a dog’s mouth. However, there are good reasons to discover problems before they arise. If a dog’s teeth are misaligned, or if there are retained baby teeth, it can cause undue rubbing on the enamel and eventually lead to abscesses or painful teeth that need to be removed, causing a dog to not want to eat and become thin.
If there are hereditary defects, such as an overbite or an underbite, or missing teeth or misaligned teeth, you should consider not breeding that dog into your bloodlines because it will create the problems mentioned above and can be passed on down the bloodlines.
Puppies have 28 Baby Teeth (12 incisors, 4 canine, 12 premolars). They erupt at about 3 weeks old and sometime between 4 months and 7 months, the roots start to disintegrate and they eventually fall out by month 7 and are replaced by 42 permanent teeth (12 incisors, 4 canine, 16 premolars, 10 molars).
A puppy grows so much in the first year, you should wait to evaluate bite in a dog until they are a year old. In saying that, however, you should check for the above-mentioned problems during the change from puppy teeth to adult teeth. If you notice something that is not right, check with your veterinarian and have it addressed before the bite is permanently formed at maturity and keep notes on which dogs have issues so you can make informed decisions about breeding.