Dentistry lectures are always especially popular at Congress – and even more so when a leading expert shares their skills.
Americans are well known in this country for the high quality of their dental work and so perhaps it is not surprising that even their pets can receive cutting edge orthodontic care. A leading exponent of veterinary dentistry from the US has been invited to pass on his skills to his British and European colleagues at BSAVA Congress in Birmingham in April. Among a series of presentations on different aspects of oral surgery, Professor Bill Gengler of the University of Wisconsin will outline the principles of orthodontics to correct conditions resulting from malocclusions.
From man to beast
Appliances similar to those originally developed in human dentistry are used with increasing frequency in dogs on both sides of the Atlantic to create a more regular bite. But in contrast with human orthodontics these methods are never used simply for cosmetic reasons. “The orthodontic procedures that we do perform are only for the health and comfort of the animal,” he explains. As a member of the American Veterinary Dental College, he uses these techniques to prevent or to treat the painful consequences of malocclusions, not to give the dog’s owners hope of success in shows. “As a group, we are very ethical and try not to change the appearance so it will have an advantage in the ring. We also encourage owners to neuter animals that have orthodontic treatment resulting from hereditary defects.”
Problems and solutions
Two defects which these methods are often used to treat are linguoversion of the mandibular canine teeth (or base narrow canines) and rostroversion of the maxillary canine tooth. The former can be a very painful condition and occurs mainly in long-nosed dogs such as Labradors, German Shepherd Dogs and Standard Poodles. Affected animals have very narrow mandibles and lower canine teeth that erupt vertically, with the result that over time the lower canine teeth drill holes through the roof of the mouth into the nasal compartment, allowing food and debris to cause a septic rhinitis.
The latter condition occurs frequently in Shetland Sheepdogs but can also occur in a wide range of other breeds including Italian Greyhounds, poodles, and many types of terrier. It is also seen frequently in cats, and in both species causes lip trauma, periodontal disease and temporomandibular joint pain.
The underlying principles of orthodontics are to induce movement in the malpositioned tooth by applying gentle force on the periodontal ligament. This will result in migration of monocytes to the immediate area and their differentiation into bone-resorbing osteoclasts in the direction of the tooth movement and into new bone-forming osteoblasts on the opposite side. To avoid damaging these structures, the required force should not exceed the capillary blood pressure of the ligament. While they can be applied constantly or intermittently, pressure for at least six hours a day will be necessary to reposition the affected teeth, he explains.
Basic skills to future trends
While describing the novel technologies and surgical methods needed to achieve these changes, Prof. Gengler will emphasise the importance of more fundamental veterinary skills in achieving a good visual appearance and functional result. “The key messages that I want to get across are the importance of knowing your oral and dental anatomy and carrying out a thorough oral examination.”
Radiography and conventional photographs are essential in planning appropriate treatment, he says. “As in many situations, the inexperienced ‘newby’ will encounter problems through underestimating the problem at hand or failing to think through the treatment plan. With orthodontics it is important to be able to think in three dimensions. It is essential to be able to understand what effects the appliance you are using will have on the other oral structures.”
As well as bringing colleagues up to date on current methods, Prof. Gengler will also be able to highlight future trends. “What is over the horizon? Well dental implants are already here but not widely used and they will likely be used increasingly with time. Jaw lengthening or shortening for the correction of malocclusion through distraction osteogenesis may become more prominent in the future. And the use of allografts or xenografts for reconstructive surgery following surgery for oral cancers is another new frontier.”