A Removable Orthodontic Appliance for Dogs
Leen Verhaert Belgium
Lingually deviated/displaced mandibular canines are a relatively common orthodontic problem in the dog (1-6). This malocclusion may be due to a dental abnormality, a skeletal abnormality or a combination of both (7,8). This condition is more than just an esthetic problem. Due to the palatal contact of the mandibular canine crown tips, this condition frequently causes discomfort and pain and may lead to mucosal ulceration, infection, and even oronasal fistulation (7-10). Treatment modalities for movement of the maloccluding teeth may be undertaken using fixed appliances: inclined plane (direct or indirect) (11-14), telescoping inclined plane (15), and active devices (expansion screw, W-wire, modified quad helix) (2,8,16). Other treatment options include surgical repositioning (17-19), surgical crown reduction, and extraction (8,10,19,20).
All of these techniques have certain advantages and disadvantages, which have been reviewed extensively (4,6,21). All of them require anesthesia on at least one occasion, with some requiring it on multiple occasions.
The technique described here is a very simple, inexpensive, animal-friendly technique for correction of lingually deviated/displaced mandibular canines when no other severe malocclusion is present (22). It can be described as a behaviour modification technique utilizing a removable orthodontic device.
The technique consists of stimulating the dog to play, as often as possible, with specific rubber toys of the right size and shape. The toy should be round or oval and made of hard rubber with a smooth surface to avoid abrasion of the canine teeth. The correct size of toy sits in between and just behind the canine teeth, too large to actually fit, principally applying lateral pressure to the teeth while the dog plays. For small dogs this usually means a rubber ball of 4 cm in diameter, large breeds need one with 6-8 cm in diameter.
Correct diagnosis of the malocclusion is of major importance for success of this technique. No major jaw discrepancy should be present. The diastema between the maxillary third incisor and canine should be wide enough to accommodate the mandibular canine tooth. The idea behind the technique is that the act of playing and chewing on a suitable object might force the teeth in a more appropriate position.
The owner is advised to play with the dog as often as possible, and to take away all the other toys. Assuming a one-week learning phase before the treatment becomes effective, two further weeks will be needed before any benefit from the treatment is likely to be seen. Therefore the occlusion is checked after three weeks, then again at further monthly intervals as necessary. If no movement is seen after three weeks, other treatment methods should be considered.
Over 50 cases were followed for between two weeks and two years. Most dogs were very young (less than seven months of age). No relapses were reported following use of this technique. There seems to be little risk of over correction (labioversion), since it never happened in any of the dogs treated. The technique worked in the majority of cases, often taking no longer than a few weeks for correction. Results will be presented with emphasis on correct diagnosis of the malocclusion. The major reasons for failure of the technique were occlusion problems other than lingual displacement of the mandibular canine teeth.
ADVANTAGES OF THE TECHNIQUE
The technique with the rubber toy avoids the necessity of anesthesia. As with any orthodontic technique, it would be advisable to obtain full pre- and post-treatment impressions, but for understandable reasons owners do not want their dogs to be anesthetised just for that. As a compromise, hard wax bite wafers can be used to record crown tip positions in most conscious dogs. Photographs should be taken to record the degree of malocclusion and as a further means of recording malocclusion and success or failure of treatment.
The technique with the rubber ball has several other major advantages when compared to working with the commonly used appliances. Good oral hygiene is not mandatory for successful outcome when using the rubber ball technique although it should be advised for prevention of periodontal disease. Oral soft tissue trauma from pressure, inflammation, and ulceration are unlikely with this technique and jaw growth will not be inhibited as is seen with some of the fixed appliances.
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