Examining your pet's mouth can be a challenge. Start your oral exam with some good loving and then gently lift your pets lips to allow for visualization of the gums. Dogs tend to be more amenable to this than cats - one trick with cats is to have them on a counter or table facing away from you and then pull their lips back. Gums should be pink and not bright red. Some animals will have dark pigment spots on their gums and tongue and this is normal. If your pet's gums look red or swollen this can be an indication of periodontal disease. As this condtion worsens the gums will recede leading to loss of bone around the teeth which means increased sensitivity, loose teeth and increased risk of a tooth root infection.
Next examine the teeth. They should be white and clean with a smooth surface. Make sure you get a good look at those far back molars as they are the teeth most prone to heavy tartar and fractures. Even superficial fractures of the enamel can lead to pain and risk of infection. If caught early, these kind of fractures can be smoothed and have a sealant applied to protect the tooth from furhter damage. Fractures that extend into the pulp cavity require either extraction or a rool canal.
And of course take a good whiff of your pet's breath - it may not smell fabulous but it should not smell rotten. Other indications of dental disease can be excessive drooling, reluctance to chew on things or groom themselves.
If doing an oral exam becomes a battle with your cat or dog then a visit to your veterinarian or veterinary technician can be a help. Sometimes strong resistance to letting you look in their mouths can be due to the fact that their mouth hurts. Being proactive is always the best plan - and can save you significant money and keep your pet happy and healthy!