Which type of restraint is safest when examining aggressive dogs?

Using a muzzle for restraint during the examination of aggressive dogs is regarded as the safest option primarily because it minimizes the risk of bites while still allowing the veterinary staff to safely assess the dog's condition. A muzzle can help protect both the dog and the personnel involved. It prevents the dog from biting, helping to ensure that everyone remains safe during the exam.

Muzzles are particularly useful because they can be applied quickly and might not require extensive handling of the aggressive animal, which could provoke further agitation. Additionally, many dogs can still breathe comfortably and can be calmed easier with verbal reassurances while wearing a muzzle.

While chemical restraint is another option, it requires time to take effect and may not be suitable in all situations, especially emergencies. Physical restraint without equipment carries a higher risk of injury for the handlers and the dog. Leash restraint can also be risky as it might lead to a situation where the handler is in close proximity to the dog's mouth, increasing the likelihood of a bite.

Thus, the use of a muzzle serves as a pragmatic and protective approach in scenarios involving aggressive dogs, enabling a safer examination for both the veterinary staff and the animal.