I remember my father as seldom smiling. When he was amused by something, you could see the muscles in his face fighting for control of his lips as he tried to avoid revealing his teeth. He had shocking teeth, you see. Not Shane MacGowan shocking, but yellowed by years of smoking and avoiding dentists. Sadly, they're two vices I share. I did return to dentistry a few years back, but was put off again after an extraction that went badly wrong and ended with jagged shards of tooth embedded in my gum. On my check-ups - roughly every seven years - the dentist always professes amazement that I don't need fillings. But I know that even my insanely vigorous brushing (which has the side effect of scratching the enamel) will not save me from my father's smile for ever.

The benefits of flossing have often been explained to me - it fights bacteria, helps with plaque, protects against gum disease, helps you pay off your mortgage quicker - and it is to a packet of Boots floss that I turn in my bid to up my dental hygiene. Eventually. But habits are as hard to pick up as they are to break, and it takes a fortnight after my decision to floss for me to remember to actually do so. I have been promised a sense of toothsome revelation: an unparalleled feeling of oral cleanliness, combined with a sense of horror that the gaps between my teeth could harbour so much mealtime detritus.

No such revelation arrives. My teeth are not evenly spaced. The street of my gums is occupied by detached houses of teeth, surrounded by broad pink lawns, or tightly packed white terraces. There are none of the little alleyways into a which a piece of floss can easily slide. So those troublesome bits of food either can't get into the gaps, or they don't lodge there. And the effort of forcing the floss into gaps that don't exist sees me cut open my gums several times, as I force the floss through with such effort that it saws into me like cheese wire.

Floss and I, it seems, are unlikely to be friends. My loss, I know.