Dental issues are reportedly common in rescue bears due to years spent in captivity, when they often chew on their cage bars as a response to stress. Photo courtesy Animals Asia I have worked at Animals Asia for six years as a senior veterinary surgeon at the Vietnam Bear Rescue Center and within the Veterinary and Behavioral Husbandry Services department. Our work within the sanctuary focuses on the bears’ overall health, incorporating their physical, mental, and emotional needs. This holistic approach means we can aid a well-rounded recovery for often very unwell and traumatized bears that are farmed for bile extraction for use in traditional medicines. Often, after the rescue, bears arrive with severe dental problems from having been captive for many years in rusty metal cages, often chewing on the bars as a stress behavior. Also, poor diets when captive and being used for bile extraction will exacerbate the condition of their teeth and overall oral health. Anyone who has had problems with their teeth is all too aware of how painful and insufferable it can be, so providing treatment for bears with broken or decaying teeth is high on the agenda for Animals Asia’s veterinary teams, and as part of our lifelong care promise post-rescue. Veterinarians have become so versed in advocating for quality dental care of companion animals due to the inability of their guardians to recognize the pain their pets are suffering. We advocate for the same for captive wildlife. Treatment, procedures, and innovations In our sanctuaries, extraction has been our most common mode of treating fractured teeth. However, as with many veterinary species, this procedure is not without possible complications for bears. The very large root of the canine teeth provides not only a strong anchor of the tooth to the jaw but also a large volume that contributes to the jaw’s structural integrity. Removing the bone overlaying the lateral aspect of the tooth and extracting the tooth leaves a thin bone bridge (3 mm on some CT scans). It is easy to understand why any levering of the tooth risks fracturing that boney bridge, leading to a fractured mandible or a communication between the alveolus and the nasal cavity that is now at risk of forming an oronasal fistula. Alternative therapies for extraction have been considered in the past. However, poor technique and using tools designed for humans did not resolve the disease. Additionally, bears get systemic hypertension, and we treat this with cardiac medications, including calcium channel blockers. However, bears also appear to have an individual, dose-dependent unintended response to forming gingival hyperplasia.1 This complicated cycle requires us to monitor dental health due to these possible complications while also ensuring that they are appropriately medicated. We also ensure we do not have sustained dental disease from periodontal disease due to the presence of gingival hyperplasia while also treating systemic hypertension to prevent end organ damage and the formation and progression of aortic aneurysms that can lead to dissection or rupture. Rescue bear Rae was the first patient at the Vietnam Bear Rescue Sanctuary to receive a root canal in place of a tooth extraction. Case study: Rae In place of extractions, we have been performing root canal therapy on our bears, which is less painful and requires far less recovery time: one night of close monitoring post-anesthetic with no change to diet or extra pain medication versus up to three weeks of recuperation and need for much pain relief. Rescue bear Rae was the first to receive this treatment from me at our Vietnam Bear Rescue Sanctuary. Performing a two-stage root canal treatment means filling the tooth with material to clear the infection within it, then following up with a second stage, which is a permanent filling material used to obturate the root canal. The procedure and materials used for Rae were the same as those used for human root canal therapy, but they used much larger tools. Rae’s canine tooth is 67 mm long, and human-sized files for this procedure are ~30 mm long. The veterinary market now has a range of files up to 120 mm long. We use the files to remove the debris from the canal and remove infected material that lines the root canal by using files that become bigger and bigger in size—a combination of mechanical and chemical disinfection. The veterinary market now has a range of larger dental tools, such as files up to 120 mm long. We then clean the canal by filing, flushing, then placing the calcium hydroxide paste into the canal to seal it with a temporary filling. A few months later, it was replaced with a permanent sealant and restored by a specialist Cedric Tutt, BVSc, BVSc(Hons), MMedVet (Med), Diplomate EVDC, during his dental week with the sanctuary. I continue to train in advanced veterinary dentistry, and we are teaching two of our junior vet surgeons to perform this treatment. In total, we have performed more than 100 root canals on our bears; with a much less invasive solution to their discomfort, with far less recovery time and the need for strong pain-relief medication. From the expert’s mouth For the last three years, Animals Asia has been supported by Dr. Cedric Tutt, who practices advanced dentistry and oral surgical options. Here, he reiterates the impact of dental diseases on animals, particularly bears: “Dental disease is debilitating in any species, and because bears have such a high level of dental disease, the debilitation that it causes is greater. With dental disease comes bacteremia, which means bacteria circulating around the body that can settle anywhere in the body and cause problems. There needs to be more research and resulting evidence on this with regards to cause and effect, but there are associations [working on learning more about it], so when, for example an animal passes away and a post-mortem is done where there was known dental disease, they might also find there was liver disease, or others. Whilst we can’t yet say dental disease caused the liver disease, there is clear indication the two or three diseases were present at the same time. Therefore it’s important in the wider sense to address dental issues for the overall welfare of an animal.” Challenges Bear teeth are much larger than human, cat, and dog teeth, so the tools to complete dental procedures have not existed on the market until recently. Before, this work could require trial and error, with custom-made tools to get the job done. However, the procedure needs to be done well to be successful. These are challenging procedures, the poorer the technique, the poorer the results. This procedure is one where if you cannot or will not do it well, then pursuing this route of treatment is not in the best interests of the patient. Treatment failures due to poor technique will lead to unacceptable and unnecessary suffering of the patients. Examining a bear’s mouth is difficult. However, increasingly, many of the bears at the sanctuary now participate in monthly dental checks through our dedicated work in cooperative care. This means they will voluntarily open their mouths, allowing the vets or vet nurses to look in the mouths for any abnormalities that have not been noted and enabling us to create a diagnostic and treatment plan. Rarely, compared to the amount of dental disease we see, can animals show us they have toothache. Although progress is being made in this area, it can be difficult to identify and read an animal’s pain signifiers. Sometimes, we will notice things, such as drooling or only eating on one side of the mouth, that indicate there is likely pain in the mouth. Dr. Thomson performing a root canal procedure on rescue bear Rae. We treat any tooth with pathology that could cause pain in humans as a possible source of pain in animals, too. This is why dental X-rays are so important when assessing oral health—not all diseases below the gum will cause disease above the gum. For conditions with a low risk of causing pain (e.g. discolored teeth), we may take the approach of monitoring that tooth with X-rays. Then, if we see any additional pathology, we treat the tooth as there is an increased risk of it being painful. We treat animals where we cannot do this intensive monitoring from the outset, ensuring the potential source of pain is removed. As with all medicine, it is about balancing the odds to do the least harm. A rescue bear undergoing root canal therapy performed on a fractured left upper canine tooth. What’s next? Having applied several different types of root canal filling material, we are now looking to analyze the clinical results in these bears to see if there is an ideal filling material for the market. This is a balance of good flowability to fill the canal, and antibacterial activity while also being good stewards of antibiotics, biocompatibility, and setting time. Due to the time necessary for full assessment of a successful root canal treatment (greater than six months post-treatment) and the bears coming to hospital only every two to three years, these results take time. So far, of the bears we treat, more than 100 teeth treated, only two have required revision to surgical apicoectomy, and we eagerly await the reassessments of these treatments. Having looked at several bear species, the anatomy of the molar teeth is likely more complex than it appears on 2D X-ray. Considerations for the treatment of these teeth likely require 3D imaging modalities. This complex pulp canal anatomy is possibly also reflected in the canine teeth, where an apparently round canal on 2D images may have a different 3D structure (e.g. figure of 8 shape), and failure to identify and treat this properly may lead to infected material staying within the canal. We are looking into these morphological differences and the use of tools, such as cone-beam computed tomography (CBCT), is likely to be required. Shaun Thomson, MBA (HEC Leige) BVSc, is a senior veterinary surgeon at Animals Asia's Vietnam Bear Rescue Center, with more than a decade of experience in veterinary medicine and animal welfare. He focuses on holistic care for bears rescued from bile farming, advanced surgeries, and veterinary education. A graduate of Massey University, Thomson has led innovative projects, including the veterinary planning for the Animals Asia Bach Ma Bear Rescue Center in Vietnam and the development of a bespoke cloud-based ERP/PMS system to enhance animal care and organizational efficiency. He earned his MBA from the University of Liege in 2022 and is studying veterinary epidemiology and public health at the Royal Veterinary College in London. Reference Sanki R and Linney C (2024), Gingival Hyperplasia as a side effect of amlodipine use in Asiatic black bears. Manuscript in preparation. Dental issues are reportedly common in rescue bears due to years spent in captivity, when they often chew on their cage bars as a response to stress.
