I love a new word, and here’s a brilliant one: diphyodont.
It sounds like something that ought to have roamed the Earth alongside a diplodocus, but actually it describes a developmental attribute that humans and dogs share: we grow two successive sets of teeth during our lifetime.
In humans, this results in a shiny five-pence piece being left under your pillow by the tooth fairy — well, that was my experience, which probably tells you something about inflation, or my age. In puppies, it results in gappy grins, suddenly enormous-looking adult teeth and a brief Bugs Bunny stage that manages to be both charming and slightly disturbing.
But what is happening inside your puppy’s mouth during those few months is much more sophisticated than simply swapping one set of teeth for another.
How many baby teeth do puppies have?
Most puppies have 28 deciduous teeth, commonly called baby or milk teeth. These begin to erupt when puppies are only a few weeks old.
Later, these are replaced as part of the development of the adult dentition. Most adult dogs have 42 permanent teeth: 12 incisors, four canine teeth, 16 premolars and 10 molars. According to the Merck Veterinary Manual, permanent teeth generally begin appearing at around four to five months of age, with the adult dentition usually complete by approximately seven months.¹
That is an extraordinary amount of dental redevelopment to fit into a relatively short period of puppyhood.
And those notoriously sharp puppy teeth have a purpose.
Why are puppy teeth so incredibly sharp?
Anyone who has lived with a puppy will know that their baby teeth are disproportionately effective weapons. They are tiny, fine and needle-sharp, and it can feel as though evolution has played a particularly cruel joke on anyone attempting to cuddle a young puppy.
However, those sharp deciduous teeth are functional.
In my teaching and work with puppies, I describe their sharpness as part of the mechanism that helps facilitate the weaning process. As puppies develop teeth and continue attempting to suckle, nursing becomes increasingly uncomfortable for their mother. Alongside the puppies’ growing nutritional requirements and increasing ability to consume other foods, this helps drive the transition away from dependence on milk.
Ouch, ouch, ouch. Poor mum.
Those delicate little puppy teeth are perfectly adequate for early puppy life, but the adult dog needs something rather more substantial. The permanent dentition is larger, stronger and suited to the feeding and behavioural demands of adult life.
But the really clever bit is how the body gets rid of the old teeth.
What happens to the roots of puppy teeth?
Long before you notice a wobbly tooth, something fascinating is happening inside your puppy’s jaw.
The permanent teeth have been developing within the jaw before they become visible. As dental development progresses and a permanent replacement tooth begins its journey towards eruption, the baby tooth does not simply get physically pushed out from underneath.
Instead, its root is gradually resorbed.
Specialised cells involved in the resorption process break down the hard tissues anchoring the deciduous tooth. As the root disappears, the little crown you can see above the gum becomes less and less firmly attached.
Imagine a tree whose roots are gradually disappearing underground. The trunk may still look perfectly normal, but eventually there is almost nothing left holding it in place.
That’s essentially what is happening to a puppy tooth.
By the time it becomes noticeably wobbly, much of its root has disappeared. This is why, if you are lucky enough to find one on the kitchen floor, it may look surprisingly small and almost hollow rather than resembling a miniature version of an extracted adult tooth.
The body has done most of the removal work before the tooth ever falls out.
Is it normal for puppies to swallow their baby teeth?
Absolutely.
In fact, this is probably where most puppy teeth go.
They may fall out while the puppy is eating, chewing or playing and simply be swallowed without anyone noticing. For most puppies this is entirely normal and causes no problem at all.
Owners are therefore often surprised by how few teeth they actually find.
My Japanese Spitz, Truly Scrumptious, was almost clockwork in the timing and sequence of her tooth changes and, despite me being ridiculously vigilant about looking for them, I found precisely two.
Twenty-eight baby teeth and only two souvenirs. Frankly, I felt slightly cheated.
When do puppies get their adult teeth?
There is individual variation between puppies and breeds, but the transition happens remarkably quickly.
The permanent incisors generally start appearing first, from around four months, while the canine teeth typically erupt later, at around five to six months. Premolars and molars also emerge during this period, with the final adult teeth generally present by around six to seven months.¹ ²
This explains that rather wonderful stage when a puppy can appear to have a completely different mouth every time you look at them.
One week there are tiny white needles. Then there are gaps. Then enormous adult teeth seem to appear in a jaw that hasn’t quite caught up with them.
And suddenly that unmistakable puppy face begins to change.
When should I worry about my puppy’s teeth?
Although changing teeth is a normal developmental process, it is worth occasionally having a gentle look inside your puppy’s mouth.
One thing to watch for is a retained deciduous tooth. This is a baby tooth that remains in place when its permanent successor has begun to erupt.
This matters because two teeth occupying space intended for one can alter the position of the permanent tooth, create overcrowding and trap food and debris. Small breeds are particularly prone to retained deciduous teeth. Veterinary guidance recommends assessment and, where appropriate, extraction rather than simply leaving a retained tooth indefinitely.³
It is also sensible to speak to your vet if you notice unusual swelling, obvious pain, persistent bleeding, a badly positioned adult tooth, difficulty eating or anything else about your puppy’s mouth that concerns you.
Puppy teeth are another sign that puppyhood doesn’t last long
For me, there is something rather poignant about the transition from puppy teeth to adult ones.
We spend the first few weeks wishing those needle-sharp little horrors would disappear — especially if we have a puppy who enjoys using them — and then suddenly they do.
Those gappy grins and ridiculous oversized teeth are another visible reminder of just how quickly true puppyhood passes.
With Truly, I found myself feeling unexpectedly sad about it. My baby was turning into a teenager.
Still, there was compensation. Her brand-new permanent teeth were such a sparkling, brilliant white that I genuinely thought she could model for a toothpaste commercial.
Puppy development is full of these tiny transitions. Some are behavioural, some emotional and some physical, and many happen almost without us noticing.
The changing of the teeth happens to be one of the most visible — provided, of course, you know what you’re looking at.
And finally… if you think puppy teeth are clever, meet the manatee
Dogs and humans may be diphyodont, but nature apparently looked at the manatee and thought, we can do better than that.
Manatees use a system known as horizontal tooth replacement.
Rather than having one set of teeth replaced vertically by another, new molar-like teeth develop towards the back of the jaw. The teeth gradually migrate forwards, rather like a very slow dental conveyor belt. As the oldest teeth at the front become worn, they are lost and replacement teeth continue their journey forward from behind.⁴
And this isn’t just a juvenile process. It continues throughout the manatee’s life.
There is a very good reason for it. Manatees consume tough, abrasive vegetation, which places enormous wear on their grinding teeth. Research into manatee dentition has shown that this continuous horizontal replacement system is an adaptation to that demanding diet.⁵
Honestly. Nature.
Hats off to you.
Further help with puppy behaviour and training
Teething is only one of the enormous number of developmental changes taking place during the first few months of a puppy’s life. Learning, emotional development, social behaviour and habits are developing at extraordinary speed too.
If you’re local to the Henley-on-Thames area in the UK and would like individual help getting those early months right, my Elite Puppy Behaviour & Training Programme provides one-to-one coaching with me, including practical training in your own home and the real-life environments in which you need the behaviour to work.
Elite Puppy Behaviour & Training Programme:
https://sarahwhitehead.com/puppy-behaviour-training-programme/
For puppy owners further afield, my online education platform also contains puppy training and behaviour resources that can be worked through from home.
Sarah Whitehead Online Learning:
https://sarahwhitehead.thinkific.com/
