Puppies have 28 temporary (deciduous) teeth that erupt from about 3 to 8 weeks of age (14 in each jaw), and 42 permanent teeth that replace them (20 upper, and 22 lower) beginning at about 4 months and being complete by 6 or 7 months.  The first deciduous teeth to come in are the canines, followed by the incisors and the premolars (there are no deciduous molars).  Each puppy tooth should be lost before its corresponding adult tooth erupts, but sometimes a deciduous tooth is retained.  Retained deciduous teeth can affect the dog's bite, or occlusion, so a veterinarian should be consulted if this occurs.  The sequence in which permanent teeth erupt is from front to back:  incisors, canines, premolars, and lastly molars.   

In the adult Frenchie, each side of the upper jaw normally has 3 incisors, 1 canine, 4 premolars, and 2 molars.  Each side of the lower jaw has 3 incisors, 1 canine, 4 premolars, and 3 molars.  However it's not unusual for one or more teeth to be absent in Frenchies as in brachycephalic breeds in general.  Each type of tooth has a specific function:
    •  Incisors cut and nibble food
    •  Canine teeth hold and tear food
    •  Premolars cut, hold, and shear food
    •  Molars grind food.

The way that the upper teeth align with the lower teeth is called occlusion; and the surfaces that come in contact are the occlusal surfaces.  In Frenchies, unlike in most other breeds, the correct bite is slightly undershot, which means that the lower jaw is longer than the upper jaw so that the lower teeth protrude slightly in front of the upper teeth.  If the upper and lower jaws meet each other edge to edge, this is called a level bite, and is incorrect in Frenchies.  Also, if the upper jaw is longer than the lower so that the upper teeth protrude further than the lower, this is termed "overshot" and is also incorrect in Frenchies.

Wry mouth (wry jaw) occurs when one side of the jaw grows more than the other so that the jaws are not symmetrical.  A detailed description of this fault follows.  Wry mouth is thought to be inheritable, and difficult to correct in a dog.  It can cause problems in grasping and chewing food

A Frenchie's teeth are not oriented the same way as a long-nosed dog's teeth because of the short jaws.  This means that its biting and chewing are less efficient because the incisors don't meet and because the premolars, in particular, are less effective in holding and chewing.  This can also cause more of a predisposition to gum disease.  It is important to keep a Frenchie's teeth clean so as to avoid periodontal problems, which can lead to serious health problems, some of which are life-threatening.  Special toothpaste can be used, and a dog who becomes accustomed to having its teeth brushed while a puppy is more likely to tolerate it well as it matures.

GLOSSARY OF CANINE DENTAL TERMINOLOGY

Anatomiske vilkår

Alveolus:  the socket in the jawbone into which the root of the tooth fits.

 Apex:  the tip of the root of a tooth.
Apical foramen:  little openings in the apex of the root through which nerves and blood vessels pass into the root canal.
Cementum:  the bony layer that covers the surface of the root of a tooth.
Crown:  the part of a tooth that is covered with enamel.
Cusp:  a rounded or pointed eminence on or near the chewing surface of a tooth.
Deciduous (Primary) teeth:  the "baby teeth" that are lost and replaced by permanent teeth.