Be afraid, be very afraid. Australian dentists are joining the ranks of the undead this Halloween to spook parents into giving trick-or-treaters apples and cheap toys, rather than lollies.

The Australian Dental Association (ADA) has issued a stern warning that tooth decay and cavities are the twin evils lurking beneath the sugar frenzy of modern day Halloween.

Professor David Manton, Vice Chair of the ADA’s Oral Health Committee, cautioned parents that children who had tooth decay early were at risk of having more dental problems later in life.

Prof Manton said that regular sugary drinks and food were the number one cause of tooth decay and parents should encourage kids to divert their sugar-munching energies into playing games.

“The ADA understands that sugary treats play a role on occasions such as Halloween, however, we encourage that sugary treats be consumed only in moderation.

“Families should consider having a sugar break the week before and the week after, just to offset the sugar hits that will come on Halloween”, Prof Manton said.

To get its anti-sugar message across, the ADA has created the shadowy figure of the Sugar Bandit, an enigmatic, masked maverick who tempts little kids with sweet treats.

But pull off that mask and knock off that stetson and underneath could lie the kindly, smiling face of a grandparent; a benevolent aunt or a feeder parent storing up dental diseases for their little treasures later on in life.

An ADA Halloween survival guide advises parents to set limits on sugary treats, stop children from grazing on sweets over many hours and to make sure children clean their teeth thoroughly before bed-time.

The dentists are also keen to explode the myth of ‘healthy’ snacks that, on closer inspection of nutritional information, are just as bad for teeth. This list of shame includes fruit juice, dried fruit, crackers, muesli bars, flavoured popcorn, biscuits, sweetened yoghurt, fruit bars and banana bread.

Research shows that more than half of all six-year-olds have some decay in their baby teeth and by the time children are 12 almost half have decay in their permanent teeth.

“This Halloween children can still have their treats and lots of fun, provided we teach them the right healthy eating tricks,” Prof Manton said.

Halloween hasn’t always been about dressing your children up as ghosts and witches and parading them around the streets collecting lollipops, fizzy worms and chewy fruit bugs.

Dentists will be hoping to wind back modern trick-or-treating to its relatively healthier pagan and Christian beginnings and away from post-war 1950s America, when war-time sugar rationing was abandoned and confectionary companies went into marketing overdrive.

Halloween has its roots in the ancient, pagan Celtic festival of Samhain around 2,000 years ago in Ireland, the UK and northern France, when people would light bonfires and make edible offerings to honour the dead, who they believed came back to earth on Samhain.

There are various theories about the origins of trick-or-treating. One is that the practice dates back to these ancient celebrations, where people disguised themselves in animal skins to drive away the spirit visitors. In Medieval times, people started dressing as ghosts and demons and performed in exchange for food and drink. This was called mumming.

In 1000AD the Church declared All Soul’s Day on November 2, as a day to honour the dead after Christianity spread to Celtic lands. English celebrations were similar to Samhain, with bonfires and masquerades.

On All Soul’s Day, poor people would visit the houses of wealthier families, who would give them pastries called soul cakes (not approved by the ADA, who list baked goods as another nasty) in exchange for a promise to pray for the souls of the family’s dead relatives. This was called souling and was later taken up by children who would go from door to door asking for gifts such as food, money and ale (unlikely, too, that the ADA would support giving ale to minors).

Scotland and Ireland had their version of trick-or-treating: guising, where people dressed up in costumes and would visit households. In return for a ‘trick’, which could be a joke, poem or song, they would be given fruit, nuts or coins – a much healthier option, although ADA warnings on dried fruit masquerading as a ‘healthy’ snack should be heeded.