Retained Deciduous Incisors By Patricia Doescher A frustrating, although non-debilitating problem with some Shiba Inu puppies is that of retained deciduous incisors, the six top and six bottom baby teeth in front. This condition doesn’t become evident until the primary (adult) teeth start to replace the deciduous teeth around four months of age. It is quite disheartening to the breeder as retention of these teeth can cause a positional deviation in their replacement teeth. As a primary tooth begins to replace a deciduous tooth it triggers that root to disintegrate allowing the tooth to fall out leaving room, or path, to allow for the exchange. This process doesn’t always take place, as it should with the Shiba Inu whose roots seem to be very strong. The timing of tooth conversion is a crucial factor to a correct bite in regards to this problem. If the lower incisors cut through prior to the top, this will usually set the stage for trouble. The lowers will be grown so far in, that by the time the uppers appear, the uppers won’t have a chance to overlap them and will take a permanent position locked in behind the lower teeth when the mouth is shut. Even as the puppy’s head matures this arrangement will remain locked with no chance to change to the correct position. The detainment of the top primary incisors is also a contributing factor. When the upper deciduous teeth roots do not disintegrate, as they should, the replacement tooth is slowed and has no recourse but to slide into position in back of (behind) the upper puppy tooth. This sets the primary tooth back a bit and if the corresponding lower tooth is already in position, as mentioned above, there is even less chance of a proper bite. Ideally you would like the primary incisors to break surface at about the same time, positioning both upper and lower teeth into the proper alignment for clear growth. Retained deciduous incisors can leave the primary incisors twisted, turned or scrambled and possibly with an anterior cross-bite, where the premolar relationship is normal but half the bite is in a normal scissor position and the other half incorrectly reversed. The bite might also look undershot, where all or most of the lower teeth sit in front of the upper teeth, yet the occlusion (proper alignment of teeth and how they fit within each other) with the molars is perfect. Pulling the puppy teeth may help to correct this problem if done early enough and if the entire root is removed. This is also within the rules and regulations of the American Kennel Club. Gently applied pressure as the teeth emerge to help them shift to the proper position may be helpful to some degree, if you can get the puppy to hold still for it! As this problem does seem to run in certain lines of Shiba Inus, it might be a deterrent from using such Shibas in breeding plans. As a breeder who has dealt with this issue I can attest to the joy of proper tooth exchange!