Happy Gas for Kids: What Actually Happens, at 3, 5 and 8

The nose mask is about the size of a matchbox. It comes in scents, and the child picks one. That is genuinely the first decision your child makes in the appointment, and it is not a gimmick: a child who has chosen something has already stopped being a passenger.

What follows is what happens in our chair at 129A Canterbury Road, broken up by age, because a three-year-old and an eight-year-old need almost nothing in common from us beyond the gas itself.

What the gas is actually doing

Nitrous oxide is mixed with oxygen and breathed in through the nose. It does not numb anything. If your child needs a filling, they still need local anaesthetic. The gas does not replace the needle; it changes how your child feels about the needle.

What it does is take the edge off. Children describe it as their legs feeling heavy, or the room going a bit further away, or tingling in their fingers. They stay awake the whole time. They can hear us, answer us, put a hand up. That last part matters more than parents expect, because the deal we make with a child is that a raised hand stops everything, and a child on nitrous is still able to keep their end of that deal.

At the end of treatment we run plain oxygen through the same mask for a few minutes. The nitrous clears, and it clears fast. There is no drowsy afternoon afterwards, which is why it suits a school-day appointment in a way that oral sedation does not.

Two things determine whether it works on a given child, and neither is age on paper:

Can they breathe through their nose? The gas only goes where the air goes. A blocked nose, a cold, hay fever in October, and the appointment is a waste of everyone’s time. We reschedule rather than push on.
Will they keep the mask on? Not “will they sit still”, because a child can wriggle. But if the mask comes off every twenty seconds, the level never builds.

Age is really a proxy for those two questions.

At three

Three is the age where nitrous most often does not carry the appointment on its own, and pretending otherwise sets a family up for a bad morning.

A three-year-old is frequently a mouth-breather when nervous. They may take the mask, then talk continuously through their mouth, which vents most of what they are breathing. They also have very little capacity to sit through the sensation of something unfamiliar happening for twenty minutes, gas or no gas.

So at three, our first question is usually not “will they tolerate nitrous”. It is “does this tooth actually need the drill today”. Very often the answer is no. This is where we use silver diamine fluoride, and we use a lot of it here, mostly on children this age. It is a liquid painted onto the decayed spot. It arrests the decay and hardens the softened tooth. No drill, no needle, about a minute of a child’s cooperation rather than twenty. The trade-off is honest and we say it up front: the treated area goes black. On a back baby molar nobody will ever see it. On a front tooth we will show you a photograph of what it looks like before you agree to it.

The other three-year-old tool is a Hall technique crown, a preformed metal cap pushed over a decayed baby molar with no drilling and no numbing. It seals the decay away from its food supply.

Where we do use nitrous at three, we use it for short, single-tooth appointments, and we use it after a visit or two where nothing happened except counting teeth and a ride up and down in the chair. Dr Linda Huang runs most of these. She takes a lot of the families who arrive after a difficult attempt somewhere else, and the aim is to treat the child in the chair rather than send them on for a general anaesthetic.

At five

Five is the age where nitrous starts doing the work it is known for.

A five-year-old can follow “breathe in through your nose like you are smelling a flower”. They can hold a mask on because they have been asked to. They understand a countdown, and a promise that something will end. They are also, usually, midway through the baby molars that decay most often, so five is when a first filling tends to land.

A typical five-year-old filling appointment here runs like this. We seat them, the ceiling TV goes on with whatever show they have asked for, and they choose their own music if they would rather have that. The mask goes on with the scent they picked and we run oxygen only for the first minute, so the first thing they experience is nothing happening. Then the nitrous comes up slowly while we talk to them about the show. When they are settled, the topical numbing gel goes on, then the local anaesthetic, which is the moment the gas is really there for. Then the filling. Then oxygen, and then they get up.

Parents are welcome in the room. The one thing we ask is that you let us do the talking during the actual treatment, because two adults narrating at once is how a calm five-year-old becomes an unsettled one.

At eight

By eight the conversation moves from managing a child to negotiating with a person.

An eight-year-old has adult molars in the mouth, usually with deep grooves that are either sealed or on their way to a cavity. They can tell you specifically what they are afraid of, which is useful, because the fear is usually narrower than “the dentist”. It is the sound. Or it is the suction. Or it is something a cousin told them. When a child can name it, we can often deal with the actual thing, and sometimes the gas turns out to be unnecessary.

At this age we also explain the treatment to the child directly rather than over their head. We show the instrument, say what it will feel like, and then do exactly that and nothing else. An eight-year-old who catches you doing something you did not warn them about will not trust you again for years.

Eight is also the age where a child can say plainly that they want the gas, and that is a good enough reason to use it.

Asthma, colds, and the medical history

Parents ask about asthma more than anything else. Asthma is not in itself a reason we would rule out happy gas, and we go through the full medical history before we plan anything. The practical issue on the day is the same one that applies to every child: can they breathe comfortably through the nose right now. A child who is congested, mid-flare, or has an ear infection gets rebooked, and we would rather move the appointment than have a child sit through treatment with gas that is not reaching them.

Bring the inhaler. Tell us what your child takes, and tell us if anything has changed since the last visit. If your child is under a paediatrician, or has a condition we want a second opinion on, we will contact them before treatment rather than proceeding and hoping.

For the clinical safety literature on nitrous oxide in children, the Royal Children’s Hospital publishes a parent fact sheet that is worth reading, and we are not going to pretend to improve on it. What we can tell you is what happens in this room.

What we do not do

We do not offer general anaesthetic. There is no theatre here and no anaesthetist. What we have is happy gas and, for some children, an oral anti-anxiety premedication taken before the appointment.

That covers the large majority of children who need restorative work. It does not cover all of them. If your child genuinely cannot be treated awake, we will say so and refer for hospital care rather than spend three appointments failing. We would rather tell you that at the assessment than after you have paid for two attempts.

We also do not do orthodontics of any kind, so nothing here is about braces or aligners.

What it costs, and what CDBS pays

The Child Dental Benefits Schedule is the scheme most Blackburn families end up using, and it does cover inhalation sedation. The item number is 88943 and the benefit is $77.60.

The rules worth knowing:

Eligibility runs from age 0 to 17, provided the child is in that range for at least one day of the calendar year and the family receives an eligible payment such as Family Tax Benefit Part A.
The cap is $1,158 across two consecutive calendar years, except that it is $1,132 if your child’s two-year window opened in 2025. Check which window your child is in before you plan a course of treatment, because the difference is real money.
CDBS is explicitly allowed in private practice. We bulk bill under CDBS.
A bulk-billed CDBS service cannot carry a co-payment. If a practice bulk bills your child and then asks you for a gap on that same item, that is not permitted.
CDBS covers exams, x-rays, cleaning, fissure sealing, fillings, root canals, extractions and partial dentures, as well as the inhalation sedation above. It does not cover general anaesthetic, and it does not cover orthodontics.

If you are not eligible for CDBS, two Victorian options are worth checking before you assume you are paying privately:

Smile Squad covers every student at a Victorian government school. There is no card requirement and no Medicare requirement. If your child is at a government primary or secondary school, they are covered.
Public dental is open to children aged 0 to 12. It is free with a concession card. Without one, it is a flat $40 per child, capped at $160 per family.

If you hold private extras, we run HICAPS on site so you see the rebate before you leave, and we are an HCF preferred provider under More For Teeth.

Booking it

Tell reception when you book that your child is nervous, or that you want happy gas, so we schedule the right length of appointment. A rushed nitrous appointment is worse than no nitrous at all, because the gas needs time to come up.

We are at 129A Canterbury Road, Blackburn, with on-site parking and a Saturday morning list from 9:00 to 1:00, which is usually easier than pulling a child out of school. Consultations are available in Mandarin, Cantonese, Teochew and Shanghainese as well as English, and having the procedure explained to a grandparent in their own language is often what settles the whole family.

Read more about happy gas at our practice, about children’s dentistry generally, or about the no-drill options we reach for before the drill.

Call us on (03) 8838 8820 or text 0435 025 318.