Q. "My daughter, who is 8, has an overbite -- it's obvious to anyone -- and yet the dentist said she shouldn't wear braces for probably four more years," writes a mother in Bethesda.

"This means that she will be going into high school mortified by a mouthful of metal and all those awful jokes about railroad tracks. "She's shy enough without that.

"But to make matters worse, the dentist wants Christy to start seeing an orthodontist now. I have this awful feeling I'm going to be ripped off. Our income takes us well out of the turnip category, but I still resent having the blood squeezed out of us.

"Should I look for another opinion?"

A. HEW advises a second opinion for any surgery, and we think it's a good idea for any treatment that will cost a lot of money or take a long time -- and braces do both.

There are, however, good reasons for a child to see an orthodontist as early as 7, even though he won't put her in braces at that age.

As a full-time teeth straightener with at least two extra years in dental school, he uses a lot of techniques now that can make the braces work quicker when she gets them, and give better results.

In the first visit the orthodontist measures the jaw and the teeth, whether they have erupted or not, and studies the profile to work out the right treatment plan. It differs with each child, since each mouth is different.

Teeth may grow in crooked or crowded or widely spaced, or the bite may be bad because Christy sucks her thumb, or pushes her tongue against her teeth, or loses her baby teeth too soon ( or not soon enough), or she may have inherited a bad bite.

The orthodontist may have to pull some teeth so the rest can grow straight, or in radical cases foreshorten the jaw.

More likely he will have your child wear a lip bumper between the lower lip and the teeth -- so the second set grow in straighter -- or braces on the back teeth, with or without a retainer. Headgear may be worn too, usually for 12-14 hours a day for 3-6 months -- an assignment that can shift the teeth permanently as much as 2 millimeters. All this is preliminary and may be enougenough.

If braces still are needed, the orthodontist is able to monitor the growth of the mouth, until it is about as big as it ever will be -- usually around age 12.

The child also must be emotionally mature enough to cooperate.

As more than one ortodontist has said, this is the key to the success of braces.

If she has this maturity you can expect Christy to accept braces in fairly good spirits -- perhaps even better than yours -- for she can look around the classroom. In some schools braces are almost standard equipment, like penny loafers and Lacoste shirts.

Turnip-wise, the cost of braces is high, but the orthodontist will charge about the same, whether your child starts now or later.

Q. "I am 9 years old," writes a child from Spring Valley.

"My parents are divorced because they were afraid they couldn't tell each other their feelings and they couldn't put it back together. Although they tried, they couldn't do it.

"Is that good or bad?

"P.S. I don't like it one bit."

A. Obviously it's pretty bad for you right now, and it must be pretty scary too.

If you're like most people your age, deep inside you think that the divorce is all your fault, or even that one day your mother or dad might divorce you.

Neither is true.

There is nothing a child could do or say that could ever destroy a parent's love for her. If you ever have a child of your own, you will find out that you no more can divorce your child than you can divorce yourself. And you accept this child the way you accept yourself -- warts and all.

And though it may be hard to believe, you didn't cause the divorce either. If anything, you probably prevented if for a long time, for parents know that their child is the best of both of them. It's hard enough to give up a marriage; it's agony to give up a child, even part of the time.

If this divorce has taught you anything, you must have learned how important it is to be able to talk about feelings.

It's around your age that we start to lock them in. Finally it becomes such a habit that by the time we're adults we often lose they key. It takes practice to be honest about the things that matter most, especially the ones that hurt.

Remember that it's okay to say when something hurts you, so long as you don't blame anyone for the blame, or call them names, for that makes people feel so bad they don't hear what you're trying to say.

And if your parents would be too sad to hear about your unhappiness now, find one special person to talk to regularly -- your teacher or a neighbor lady, if your marks are getting a lot worse -- or you can't pay attention in school, you might even need a child psychologist, which your mother or father would have to arrange.

But for the day-in, day-out miseries, use a notebook.

Get a special book or pad and write down everthing you feel: every pain, every wish, every question or complaint, no matter how awful or silly they seem. It can be full of words that make no sense or pictures that are dark and scratchy. It's your book and no one else has the right to see it.

As the weeks go by, a strange thing will happen. You won't be quite so sad or so mad as you were when you started, and soon you won't need to write in it so often, and finally, not at all.

It's much better to release your feelings a bit at a time than to keep the lid on them. Otherwise you'll explode like a bottle of fizz, and you know what a mess than can make.