A learned friend, who lives on the other side of the world in a country constructed largely from number eight fencing wire, told me recently that once a person reaches fifty, they’ll generally suffer from at least two life-impacting conditions. Multi-morbidity, he explained, is the more serious category of this, where someone has more than one chronic disease co-occurring. His face Cheyne-Stoked in and out of focus on the Skype call and I may have missed some of his more critical points.  So what, you say, reaching for another rhubarb flavoured gin or a finger-pinch of oven-baked crisps.  Well he’s a doctor and a public health professional and he used to tease apart the organs of small white mice in the name of cancer research. Ah, Johnny Foreigner and an animal abuser to boot, you retort. You sip primly at the gin and one of the two chinking ice cubes rolls into your mouth and the sudden pain in a lower molar renders you temporarily senseless.

So, if you’re fifty plus and you’re still reading, you’re already counting. You’ve got your fingers out in front of you and you are ticking off those conditions one by one.  If you’ve ticked off more than two your stomach’s just dropped a level as sure as a tide on the ebb because now you know you’re worse than average. That must mean you’re actually unhealthy and this can’t be true because you go to hot yoga twice a month. I sympathise. You’re not alone. Hot yoga is not my thing. However, I once went to a spin class on account of a discount code and I had to have a lie down half way through because the room was too hot and even a hamster couldn’t have spun a wheel in those conditions which were more suited to indentured labour than sorting out the nation’s health one revolution after another.

Some of these long-term multi-morbidity conditions are clearly more serious than others. Diabetes, Chronic Obstructive Pulmonary Disease, and Stroke are all life threatening. Some are less serious; they threaten the way we’d like to live our lives rather than life itself. Mine are in the latter category. The most obstreperous, osteoarthritis, is a full time, chronically painful, occupation. I pore over Excel spreadsheets just to keep track of it all. Mechanical interference. Contraptions with Velcro. Light touch medication. People with name badges and trouser suits. Receptionists who rage, rage against the dying of their Windows XP systems and ask if you wouldn’t mind phoning them back in a month. Home exercise and subsidised gym visits. Skulduggery. And on occasion low dose Diazepam just to get through the revolving doors for the appointment.

The most recent on my list of these unsolicited freeloader conditions, a shy one in polite company, and one that my learned friend had not thought to mention, is Bruxism.  Bruxism it turns out, does not mean constant brushes with death, although to be fair, that would probably cause it. But grinding teeth and jaw clenching can, along with the menopause for a woman of my age, cause sensitive teeth. This news was relayed to me by a young Romanian woman, wearing something akin to white pyjamas with a primary colour print, whose professional qualification had not yet been accepted by the authorities. I was lying flat on my back on the dentist’s chair, my hot damp hands clutched together over my groin, trying not to grind my teeth, and wondering whether I should have just kept silent about the sensitive tooth. The woman’s boss, the diminutive Ammit, seared grey in a crocodile mask, told me to open wide, poked her lion claws into the far pink recesses of my  mouth which, incidentally, prefers to chew on the left side on account of the sensitivity, and advised me it was time to try a mouth guard.

Sweat trickled down under my armpits. Bile inched up my gullet. I imagined some monstrous red plastic palatine that would envelope my lips and slowly throttle me to death. I’m not a lover of sport, but I’ve seen boxers’ faces and, more to the point, their maws. How would I speak? What about my self-respect? My basic human dignity?  Ammit offered me a plastic cup of pink water. It’s up to you, she said as I rinsed and spat although nothing had actually happened yet. The tooth is not split she continued, scanning the x-ray. We could wait. Of course that might end up with root canal work. She coughed discretely and her sly amber eyes flashed fire. If I hadn’t already been lying on my back I would have passed out. I nodded. Through a mouthful of her claws and a mirror on a stick I was foiled. They’re nothing like you see on the telly, she said. You won’t even notice it. So if you’re ready, I need to make an impression.

The woman in the children’s pyjamas mixed something in a plastic tub. She passed it to Ammit. The putty was pink, sticky and terrifying. Ammit handed me a bubble-gum spit size of putty to put in my fingers. Now, she husked, as if speaking to a toddler, when that gets firm, it will all be done. Open up. Bite down and remember to breathe. She rammed something into my mouth. Her devil ears pointed and pranced in the thick ruff of her blond mane. I gagged. I gasped. I worked that finger putty into a frenzy. My eyes crossed and a thin line of spittle escaped Ammit’s gaze and trickled down the side of my neck and onto the paper bib. There was no way of hiding it.  And then, just as I’d moulded that putty into a voodoo doll of perfect malevolent proportions, Ammit was pulling everything out of my mouth and announcing that I’d made a very fine impression.

I arrived home with my new shame and a mouth full of instructions. The guard, made from transparent thermo polymer, came in a pink plastic tub that screams falsers to anyone that doesn’t have a mouth guard. I cleared a space at the back of the lower bathroom shelf and hid it. Not only from judging friends. But also from the thieving cat. According to Ammit, the causes of lost and damaged mouth guards occur in the following order: cats; dogs; washing machines; and other. I didn’t ask about the other. Wait, she’d called, as I’d been legging it out of the surgery with the pink tub pushed deep into an anorak pocket. I need to tell you what do.  I stopped, turned, and kept my distance.  Her thin scaly tail flicked a fly from her buttocks. Once you’ve worn it to bed for three nights in a row and it’s still there in the morning, you can move to the next stage. Two whole weeks and then start skipping a night. Oh, and never remove it using your tongue. Your tongue is wily, and if you teach it what to do, it will remove the guard itself at every opportunity. The fly was still there. Her tail shook. She glanced down at a paper in her claws. You can pay the £67 next time you’re in. Good luck! I walked along the street until I was out of sight then stopped and stared at my pocket. What did she mean if was still there in the morning? Where would it go? Might it creep down my throat and masticate in my oesophagus? Or might the cat extricate it with a judicious furry snatch while I slept, open mouthed and snoring, a gormless victim in the fight against Bruxism. Who would guard the guard?

In my rush to leave the clinic, I’d forgotten one last thing. I rang the dentist’s receptionist. The cleaning instructions were clear. No washing machines. I smirked. I wasn’t that stupid. She continued. No dish washers. I don’t have a dish washer, I said. There was a short silence as she reassessed my capacity for reason. No hot water. No scrubbing it with a toothbrush. I interrupted but she was on to me. And if you must clean it with something other than cold water, buy some denture cleansing tablets and soak it in that. I snorted. Are you kidding me? Going into a chemist and declaring I’ve got false teeth? I’d have to say they were for my rabid uncle and they’d see through me, as sure as night follows day.

As I write this, I’m into day eight of the mouth guard. It seems I may have been a touch alarmist. My dignity is still intact. I haven’t lost my self-respect. Each morning, as soon as I wake, my tongue slides gently along my lower jaw to check that the thermo thug is still there. It always is. The cat has yet to steal it. It hasn’t been drubbed by the washing machine. My jaw is slack and I clamp rather than grind. I expect to be treating my mouth guard like a lifelong chum any day now. A chum that can prevent root canal work is a special chum indeed. So, the next time an ice cube renders you senseless, don’t despair. If Bruxism is the cause, a mouth guard might just be the answer. Which brings me back to my learned friend. In 1998 a stranger on the coach travelling from Fort William to Glasgow got off at Ballachulish with my learned friend’s black trolley bag.  The doctor had to halt the bus, leap down the steps and run after the thief, gasping from the pain of his sclerotic back. The trolley bag didn’t contain life-changing work on Bruxism. It did, however, contain important research on immunology and vaccines. My learned friend has gone on to save lives on the other side of the world. And now, thanks to my foray into transparent thermo polymer, I’m urging him to order a mouth guard himself. He adores a gin, but every evening, as he sits on his balcony and watches the last of the sun’s rays melt into the harbour, an ice-cube renders him senseless.