does my child need a fissure sealant

The chewing surfaces of back teeth are not smooth. They have deep, narrow grooves called pits and fissures, often narrower than a single toothbrush bristle. Food and bacteria settle into them and the brush cannot reach the bottom. That is why most cavities in children's adult teeth start on the biting surfaces of the molars.

A fissure sealant is a thin layer of resin, or of glass ionomer (a fluoride-releasing material), that flows into those grooves and sets hard. It smooths the surface so it is easier to clean and harder for decay to start.

Which teeth, and when

• First permanent molars: these come in at around six years, behind the last milk teeth. Many parents don't realise they are adult teeth that must last a lifetime.
• Second permanent molars: around 11 to 13 years.
• Premolars and milk molars: sometimes, if the grooves are deep or the child is at high risk.

The best time is soon after the tooth has fully come through, because newly erupted enamel is at its most vulnerable for the first couple of years.

Does your child need one?

Sealants are not automatic. A dentist weighs your child's risk of decay. They are most clearly worth doing if your child:

• already has, or has had, cavities in milk teeth
• has deep, stained grooves on the molars
• snacks often on biscuits, chocolates, sweet chai or juice
• finds it hard to brush well, including children with braces or special needs
• has enamel defects such as MIH, chalky molars that break down easily

A child with shallow grooves, no history of decay and good brushing habits may get little extra benefit. It is fair to ask the dentist why sealants are being recommended for your child.

What the procedure involves

1. The tooth is cleaned and kept dry with cotton rolls and suction.
2. A mild gel is applied to roughen the enamel slightly, then rinsed off.
3. The sealant is painted into the grooves and set with a blue curing light.

There is no injection and usually no drilling. It takes a few minutes per tooth. The hardest part for a young child is staying still and keeping the tooth dry, which is why sealants placed by a dentist used to working with children tend to last better.

What can go wrong

• Sealants can chip or wear away over time. They need checking at routine visits and topping up when needed.
• Moisture during placement can make a sealant come off early.
• Sealing over a hidden cavity is a risk if the tooth is not examined properly first. The dentist checks the grooves carefully, sometimes with an X-ray.
• A sealant protects only the biting surface. It does nothing for the spaces between teeth, so brushing with fluoride toothpaste and flossing still matter.

Sealants are not on our published online fee list, so the cost will be explained at the consultation. For children under 10, ask for our MDS Pedodontics department. For more on chalky molars, see molar incisor hypomineralisation.