Developmental Dental Abnormalities In Dogs
There are several dental abnormalities in dogs which are mostly genetic. The mouth and teeth develop in a sequence of events. If this does not happen or the sequence is not in its proper order, then long term complications such as an improper bite will occur. The development is in three stages. During each of these stages, the animal should be examined by a veterinarian as there can be problems during each of the stages. Stage one begins at birth and lasts until sixteen weeks old, stage two begins at sixteen weeks and lasts until seven months old, and stage three begins at seven months and last until one and eighteen months old.
At birth, the upper jaw of a puppy is longer than the lower jaw. The long upper jaw allows them to nurse. As the puppy grows and is weaned, the lower jaw has a growth spurt. If specific deciduous teeth erupt in the lower jaw before the growth spurt, they may catch on the upper teeth and will restrict the jaw growth. This will sop the lower jaw from reaching the correct length. If this is discovered in an examination, it may be necessary to remove the deciduous teeth. With the lower teeth removed, the lower jaw should grow to the correct length, which will prevent problems in the permanent teeth. Some animals naturally develop an overbite regardless of tooth extraction. It is also possible for the reverse of this to occur. The lower jaw can grow faster than normal. If this happens, then the lower jaw is too long for the upper jaw. The result of this is an under bite. This can be seen at eight weeks of age or later. The teeth of the upper jaw may catch on those of the lower jaw which will restrict the growth of the upper jaw. Removing some of the upper teeth may help. It is important that these problems are identified and corrected early so as the long term prognosis is good.
Other problems that can occur in the first stage of dental development include extra teeth and teeth erupting in the wrong position. These should be removed if they are causing interference with the other teeth. It is also possible for the left and right sides of the jaw to grow at different speeds. If this happens, then teeth should be removed from the under-developed side of the jaw as this may allow the growth to correct itself.
The biggest problem in stage two is deciduous teeth which do not fall out. Normally, the deciduous upper central incisors begin the process of shedding the teeth. This happens at around fourteen weeks old. The lost teeth are replaced by permanent ones and this process takes around three months. Permanent teeth which do not have deciduous teeth counter parts also erupt at this time. If the deciduous teeth are not shed as the permanent teeth erupt, there may be an abnormal bite and tooth pattern in the mouth. This can be avoided by the removal of the deciduous teeth as soon as the retention of them is noticed. It is in stage two that tilting of the canine teeth in both the upper and lower jaw, which is abnormal tooth placement may appear. The treatment for this will depend on a number of factors including the age of the animal and which teeth are involved. It may be necessary to fit the animal with orthodontic braces. This is common in Shetland Sheepdogs but has been noticed in other small breeds. Overbite is often noticed at this stage and depending on the severity can be treated with a plate fitted in the mouth, tooth shortening or tooth extraction.
In stage three, it is possible for incorrect placement of teeth to occur. If the veterinarian decides that treatment is necessary then teeth may be removed or orthodontic measures may be taken. If the teeth become crowded, then it may be necessary to remove one or more of the teeth. If there are teeth with significant rotation then the rotated teeth are removed. This is can be found often in brachycephalic breeds.
It is possible that fever or chemical deposition within the tooth during the development of tooth enamel may cause permanent damage to the enamel. The distemper virus can affect the cells that produce enamel and causes a fever, which can be significantly damaging to the enamel. The result is enamel which is thinner than it should be. Other diseases which cause fever can result in weaker enamel and enamel which has not developed correctly.
Enamel defects are also seen in young dogs who are severely malnourished. If the defect is in one isolated tooth then it is most likely a result of some trauma to the tooth, or an infection. It is common for an infection in a fractured deciduous tooth to have an effect on the enamel of the permanent tooth behind. It is also possible that some enamel defects may be inherited as they are commonly seen in Siberian Huskies. Treatment options for enamel defects include fluoride treatment, bonding a synthetic material to the teeth and frequent dental care to prevent further complications.