The Tooth About Animal Dental Care
An apple a day won't keep the dentist away or—in this case—the veterinarian.
Healthy smiles aren't only important for humans. Healthy teeth, beaks and bills are just as important for animals. These structures let them snap up, chew, crunch and tear into all sorts of tasty morsels. From self-grinding tooth structures to simply replacing teeth on a routine basis, invertebrates, fishes, reptiles, birds and mammals rely on different strategies and adaptations so they can keep eating throughout their lifetimes. And yes, while some shrimp, fishes and birds play the part of "dental hygienists" in specific ecosystems, most animals make do without trips to the dentist.
However, dental and oral exams aren't optional for animals residing in human care, like those at the National Aquarium. These animals can often live beyond their usual life expectancy, thanks to a lack of predators and excellent health care. A side effect of this is that their teeth, beaks or bills can change with age. Having a varied, nutritious diet also impacts an animal's oral health, especially if certain foods or other natural materials are what help keep its mouth in shape. Vets and animal care staff must pay close attention to an animal's foraging and overall condition and do routine exams to catch any issues.
Sea urchins are known for devouring kelp and, occasionally, mussels. Scraping off algae and gnawing through mussels nourishes the urchin and helps keep its teeth in check. The urchin's mouth is ringed with five toothlike structures made of calcium that continually grow. Not only does the abrasive quality of rocks and mussel shells grind these "teeth" down, but the teeth themselves point inward and meet in the middle. This allows them to line up and grind against one another. If the grinding occurs evenly, there aren't too many issues. However, sometimes one or two may become overgrown, leading to difficulty chewing. While this type of defect might correct itself, especially if the overgrowth breaks off on its own, National Aquarium vet staff have opted for a different method of treatment in the past: a rotary tool.
Because the calcite making up the teeth is organic (produced by the urchin), it doesn't cleave or shatter at deeper levels when its surface cracks. As the outer layers gnash together and slough off, the inner ones continue growing and hardening without issue. Brief bursts of the rotary tool against the calcareous tooth plates quickly file down the overgrowth, allowing the urchin to graze and eat normally again.
Sharks are arguably some of the most well-known polyphyodonts—that is, animals that are repeatedly losing and replacing their teeth. They are far from the only ones, however. They are joined by many other toothed fishes and reptiles like geckos, other lizards, and crocodilians.
In many fishes, teeth are not only found in rows but can also appear in patches throughout their mouths. Some even have a second set of jaws in their throats, known as pharyngeal jaws. With so many hidden teeth, it can be challenging to spot poor oral health immediately. While tooth replacement allows an animal to continue catching and eating food in the long run, it does not solve other oral health issues like bacterial infections, dental fractures or misaligned jawbones. These problems are often noticed when an animal's appetite changes, and it begins losing weight due to a reluctance or inability to eat. Annual or routine exams also offer chances for detecting and treating such injuries.
As many doctors and dentists have reminded us during visits, preventive care is vital. The same holds true in a veterinary context. Animal care staff regularly offer means for animals to maintain their teeth, beaks or bills. For example, birds will use rough surfaces such as tree branches in their habitats to sharpen and file their bills. Pufferfish, with their continually growing tooth plates, are given hard clam shells to crunch on to prevent overgrowth.
In some cases, though, staff can take preventive care to the next level by either training animals to allow carers to gently brush their teeth or teaching animals to actively participate in other oral hygiene routines. In fact, one of the Aquarium's bearded dragons has been trained to clean her mouth with a sponge doused in an antibacterial liquid to help prevent gum disease regularly seen in the species.
Once a problem has been noted and treated, vet staff will often conduct more frequent exams to keep tabs on any reoccurrence. For non-invasive exams and gentle trimming via a rotary tool, most birds and reptiles tolerate holding still. Anesthesia is the preferred approach if a closer look is needed, or the procedure to correct a problem is more advanced. With an animal sedated, vet staff can handle them more easily, positioning them for more intense scans like radiographs (a type of x-ray imaging). This must be done efficiently, especially if the animal cannot stay out of water for long.
A prime example is the Aquarium's striped burrfish, whose fused, plate-like teeth occasionally need trimming. Despite having clamshells to bite on, sometimes their tooth growth outpaces the natural grinding; vets break out files and rotary tools like a Dremel to shape and cut back the excess growth. This allows the burrfish to eat normally until their next appointment.
Conducting dental and oral exams on so many different species demands creativity from the Aquarium's vet team. After all, getting an animal to open wide can be daunting, especially when its mouth is small or has an intense bite force. From leveraging mouths open with old (sanitized) credit cards or guitar picks to relying on small power drills, the vets use a diverse toolkit.
The most common solution, aside from filing or maintaining tooth or bill edges, is extraction. Since many of these animals can replace teeth, removing one will not impact the animal in the long term. Luckily, even animals that cannot replace extracted teeth adapt fairly quickly, compensating by chewing or taking food apart differently. Without needing to deal with dentures or implants—which could also be uncomfortable for the animals—the vet and animal care teams can continue focusing on exams and preventive care regimes so all the animals have brilliant, healthy "smiles."
Stay close to home with stories and videos about Baltimore's Inner Harbor and how we care for Aquarium animals' teeth, beaks and bills—and then follow us to the literal end of the Earth, to Antarctica.
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