Q: My dog is unhappy and...

Q: My dog is unhappy and destructive when left alone. Any advice?--M.N. A: Dogs left alone for long periods may suffer from separation anxiety. They may bark excessively, soil in the house or behave destructively. Because they become distressed when separated from those they love, they need to learn they are not being abandoned.

Most separation-anxiety misbehavior occurs during the first 30 minutes after the owner departs. Therefore, you should introduce the dog to separation in a gradual manner, starting with absences of up to 10 minutes. Vary the hours training episodes, because if the dog adapts to the owner’s work departures, it may still exhibit distress if left alone at other times.

Anti-anxiety drugs help with some dogs; with others, drugs can cause hyperactivity. Do not rely on any drug for more than a few weeks, and reduce dosages gradually.

Although some people claim that their dogs have a guilty look after an anxiety attack, punishment is not an effective treatment. The “guilty look” is in response to the owner’s annoyed expression, which the dog has learned to associate with disciplinary action. The dog knows that the presence of feces, urine or destroyed items will result in some form of punishment, but it seldom associates those things with prior misbehavior.

Q: When do dogs and cats get all their permanent teeth?J.S.

A: Dogs have 28 temporary or deciduous teeth that start erupting at three weeks of age. These are gradually replaced with 42 permanent teeth, and all are usually in place by eight months of age. Cats have 26 deciduous teeth; the 30 permanent ones are usually in place by six months of age.

Dogs and cats need yearly dental check-ups after two years of age. Tooth problems can be considerably reduced with a good diet, daily feeding of dry food or biscuits, and chewing bones (if not done excessivley) or rawhide. Wiping the teeth daily with a salt-and-water solution ( 1/2 teaspoonful of salt to one cup of warm water), or the use of a specially formulated pet toothpaste and toothbrush are also recommend for owners who want the best dental care for their pets.

Dr. Clarke welcomes pet-care questions for use in this column, but regrets she cannot answer mail personally. Send your questions to Pet Doctor, Home magazine, Los Angeles Times, Times Mirror Square, Los Angeles 90053.