Children can be such harsh critics. Nothing fills me with dread quite as much as the call that comes from a primary school requesting a talk from a dentist.

Oh the smell of the greasepaint, the roar of the crowd... Unless I can produce a guest appearance from Harry Styles, I know that I’m not likely to be met with much enthusiasm by a class of 10 year olds.

If only teeth were a bit more interesting, I might be able to muster some enthusiasm. I’ve been into many schools and nurseries in my time, but none so daunting as the school which I know and love, the school my children go to in Shiplake.

When I was at primary school, I don’t remember teachers being so enthusiastic.

Maybe it’s because there were less targets to meet or levels to rise through.

Maybe teachers just seem to care a bit more now.

How lucky we are to have such a happy, encouraging school on our doorstep and how I have underestimated how utterly terrifying it must be to stand up in front of a class day in, day out.

Despite not being the only dentist parent in the school, somehow I seem to have been volunteered to provide the 20 minutes of potential boredom to every class.

My own children have yet to reach the age where they are totally embarrassed by me; I would estimate a 5/10 depending on what I am wearing and whether it involves singing or any form of dancing.

I am, of course, aware that this is very likely to rise to 10/10 in the near future which will prohibit me from coming within 25 metres of them in any public place. But for now, they seemed relatively comfortable with the idea of my school visit.

As usual, preparation for my torture was minimal. Armed with a bag full of disclosing tablets; (food dye tablets to stain purple the plaque on teeth), and foods from my own cupboards I arrived at the school ready for action.

My first class was year 5, a brutal start. Not because the children are in any way difficult, but more because I had underestimated just how intelligent kids of this age can be. Faced with 30 staring faces, my woeful lack of preparation dawned on me.

Thank goodness for the child who chewed a tablet, spilt dye down his shirt and entertained the crowd with the display of a bright purple tongue. That managed to fill the first 10 minutes.

My bag of foods bad for your teeth slightly backfired though, no kid in the world is ever going to get as enthusiastic over a lump of cucumber as a bag of Maltesers.

There’s always one smartarse kid though, it’s as if they can sense a weakness. “If you brought that food in from your cupboards, how come you have all this stuff which is so bad for your teeth anyway?”

Good point. Do as I say and all that...

Reception class is always the easiest when cynicism has yet to creep in. Though I’m fairly sure that half the class misunderstood the point I was making and went home convinced that if you eat Coco Pops, your teeth go purple.

One thing I learnt is never to ask a class of children if they have any questions and expect an easy ride. You can guarantee that there will be one child who has no concept of the word question and uses it as platform to tell everyone gruesome stories of her own parents dental horrors and another couple who are destined to be abstract thinkers.

“How does a blue whale chew its food?”

“Why are they called molars?”

“How much does a dentist earn?”

After a full three hours of ritual humiliation and a school full of children with purple teeth I left, safe in the knowledge that being a teacher is 100 per cent harder than anyone gives them credit for; and that I had fulfilled my public service for the year.

Next year, I have a dentist friend whose children are starting at the same school. I’ve done my time, I’m going to be handing the reins over to her.

I had a great morning with lovely children but when I die I definitely want to come back as an accountant. They never have to do school talks. Well, an accountant or Harry Styles.