The rule that matters most for scuba diving and your teeth is that any gas trapped in a tooth, under a filling or in a crack will compress on the way down and expand on the way up, so it pays to have restorations checked before a diving trip rather than after. A pilot survey published in the British Dental Journal asked 100 certified recreational divers about this and found 41 percent had experienced dental symptoms during a dive. That is a large number, and it comes with a large caveat that we get to below.
Divers often ask how this differs from flying, which we cover in our article on tooth pain when flying. Two things separate them. The pressure change underwater is far greater over a far shorter distance, since the first 10 metres of water doubles ambient pressure, whereas an aircraft cabin changes by a fraction of that over a whole climb. And a diver has a rubber mouthpiece clamped between the teeth for the entire dive, which adds a mechanical load that flying does not.
Key takeaways
- A pilot survey of 100 recreational divers found 41 percent reported dental symptoms during a dive, but it was self-selected and the authors described it as preliminary.
- Within that symptomatic group, 42 percent had barodontalgia, 24 percent had pain from gripping the regulator too tightly, 22 percent had jaw pain and 5 percent had a crown loosen.
- Across the wider literature, reported barodontalgia prevalence ranges from 10.8 percent to 56.1 percent depending on the population studied and the method used.
- The mechanism is Boyle's law. Gas volume is inversely proportional to pressure, so trapped gas compresses on descent and expands on ascent.
- A diver symptom study found the most frequent in-dive complaints were dry mouth at 51.9 percent, clenching at 32.5 percent and jaw joint pain at 19.5 percent.
- Stock regulator mouthpieces are associated with more symptoms than custom fitted ones, and clenching to hold the mouthpiece is the identified risk to the chewing system.
What Boyle's law does inside a tooth
Boyle's law states that at constant temperature the volume of a fixed mass of gas is inversely proportional to the pressure applied to it. Descend to 10 metres and ambient pressure roughly doubles, so a trapped bubble halves in size. Ascend and it returns, expanding as it goes.
Teeth are not supposed to contain gas. But small voids exist in more mouths than you would think. A gap under a leaking filling. A void inside an old restoration. A crack running through enamel into dentine. A pulp chamber that has become necrotic, or a periapical area with gas producing bacteria. Any of those can hold a pocket of air, and any of those can hurt sharply when that pocket changes volume against rigid tooth structure.
That is barodontalgia, and it is the most common orofacial pain reported by divers. Across the literature it is reported in a range of 10.8 percent to 56.1 percent, a spread wide enough to tell you that the studies are not measuring quite the same thing as each other.
A published breakdown of causes for pressure related dental pain is more useful than the prevalence figures, because it points to what to look for. Faulty restorations, including barotrauma, together with caries not involving the pulp accounted for 29.2 percent. Necrotic pulp or periapical inflammation accounted for 27.8 percent. Vital pulp pathology accounted for 13.9 percent. Recent dental treatment accounted for 11.1 percent. Barosinusitis, which is sinus rather than tooth pain but is felt in the upper teeth, accounted for 9.7 percent.
Nearly all of that is findable at a routine examination.
Descent pain and ascent pain mean different things
The timing of the pain is a genuinely useful diagnostic clue, and it is worth noting on your log.
Pain on descent, as pressure rises and trapped gas compresses, is more often associated with a defect that lets gas in, such as a leaking or faulty restoration, or a crack. Pain on ascent, as gas expands, is more often associated with gas trapped in a space that cannot vent, which raises the possibility of a necrotic pulp or periapical infection. Neither pattern is a diagnosis on its own, and a tooth can produce pain in both directions.
Cold water adds a second variable. Water at Sydney temperatures is well below body temperature, and a tooth with exposed dentine, a deep restoration or a crack will complain about that regardless of pressure. If your tooth hurts with a cold drink on land, it will very likely hurt underwater, and our page on cracked tooth syndrome covers how cracks are found and managed.
The regulator, the jaw and the clenching problem
The other half of the diving picture has nothing to do with pressure. Holding a mouthpiece between the teeth for an hour is a sustained, unnatural task for the chewing system.
In the pilot survey, 24 percent of symptomatic divers reported pain from holding the regulator too tightly and 22 percent reported jaw pain. A separate study of in-dive symptoms found clenching in 32.5 percent and temporomandibular joint pain in 19.5 percent. Stock regulator mouthpieces are associated with more symptoms than custom fitted mouthpieces, and clenching to retain the mouthpiece is the identified risk factor for the chewing system.
The fix is largely equipment and technique. A custom fitted mouthpiece, moulded to your own teeth, means the mouthpiece stays put without a hard bite. Relaxing the jaw and letting the lips do more of the sealing work helps. So does noticing when you are gripping, which most divers do without realising, particularly when cold or task loaded. The same pattern shows up in other sports, which our article on teeth clenching during exercise looks at, and if your jaw is already sore or clicking then our guide to jaw pain causes and treatment is worth reading before your next trip.
Dry mouth underwater
Dry mouth was the single most frequent in-dive symptom in one study, reported by 51.9 percent of divers. The reasons are simple. Compressed breathing gas from a cylinder is dry by design, since moisture in a tank causes corrosion. Breathing that gas continuously through the mouth strips moisture from the oral tissues. Immersion also drives a diuretic response, so divers tend to be more dehydrated than they realise.
For a single dive this is a nuisance rather than a hazard. For someone diving daily for a week, or for a dive professional working season after season, it removes saliva's protective effect for hours every day. Rehydrating properly between dives is the practical answer, along with avoiding sugary drinks as the rehydration method, since that combines low saliva with high sugar.
What to do about a symptom
| Symptom during the dive | Likely cause | What to do before the next dive |
|---|---|---|
| Sharp pain on descent | Gas compressing in a void under a faulty or leaking restoration, or in a crack | Have the tooth examined and X-rayed. Leaking restorations usually need replacing rather than monitoring |
| Pain on ascent | Gas expanding in a space that cannot vent, which raises the possibility of a necrotic pulp or periapical infection | Get it assessed promptly, including sensibility testing and an X-ray. Do not dive again until the cause is known |
| Jaw ache after the dive | Clenching to hold the regulator, sustained over a long dive, loading the muscles and joint | Move to a custom fitted mouthpiece, work on relaxing the jaw, and get persistent joint pain assessed |
| Crown or filling loosened | Pressure change acting on a restoration that was already compromised, plus biting force on the mouthpiece | See a dentist before diving again. A loose crown underwater is an aspiration risk, not just a dental one |
| Dry mouth | Dry compressed gas breathed through the mouth, plus immersion related fluid loss | Rehydrate with water between dives, avoid sugary drinks as the rehydration method, and take dryness seriously if you dive daily |
| Tooth sensitive to cold water | Exposed dentine, a deep restoration, gum recession or a crack | Have it checked. Cold sensitivity that lingers after the stimulus is a different problem from a brief twinge |
Diving after dental treatment
Recent dental treatment accounted for 11.1 percent of cases in the published aetiology breakdown, so this is not a theoretical concern. A temporary crown or temporary filling is not designed to resist repeated pressure change or hard biting on a mouthpiece, and a temporary that comes off underwater is an aspiration risk.
Divers Alert Network guidance on implants is that you should not dive until healing is complete, osseointegration has had adequate time, and the definitive restoration is in place. The definitive prosthesis is typically made 4 to 6 months after placement. The reasoning is straightforward, since temporaries risk loosening and aspiration.
For extractions and other procedures, no organisation publishes a fixed number of days to wait, and you should be sceptical of any page that quotes one. The principles are the ones that apply to any healing wound: let it heal, do not dive with an open socket or an active infection, be aware that a regulator sits directly on healing tissue, and ask the dentist who did the treatment. Our article on flying after a filling or dental work covers the same reasoning for air travel, which is a milder version of the same physics.
How much should you trust the 41 percent
Not as much as the headline suggests. That figure comes from a self-selected online pilot survey of 100 recreational divers. Divers with a dental problem are more motivated to complete a survey about dental problems, which pushes the number up. The authors themselves described the work as preliminary.
The wider literature reflects that uncertainty. Barodontalgia is reported at 11.9 percent of divers and 11.0 percent of military aircrew in one review, with an aircrew rate of 5 episodes per 1,000 flight years. Across orofacial pain types in divers, barodontalgia has the highest prevalence but is reported anywhere from 10.8 percent to 56.1 percent depending on the population and the method.
A range that wide across studies is a signal that the true figure depends heavily on who is asked and how. What does not depend on methodology is the physics, and the fact that almost every listed cause is something a dentist can find at a routine examination before a trip.
Common questions
Why does my tooth hurt when I scuba dive?
The usual reason is gas trapped in or under a tooth changing volume with pressure, which is barodontalgia. Common sources are leaking restorations, cracks, decay and a necrotic pulp. Cold water and clenching on the regulator can also produce pain that is not pressure related.
Can I dive with a temporary crown or filling?
It is not a good idea. Temporaries are not made to withstand repeated pressure change or hard biting on a mouthpiece, and one that comes loose underwater is an aspiration risk. Wait until the permanent restoration is in place.
How long after a tooth extraction can I dive?
There is no published fixed interval, and any specific number of days you see quoted is someone's opinion rather than a guideline. The principles are to let the socket heal, avoid diving with an active infection, and remember that the regulator sits on healing tissue. Ask the dentist who did the extraction.
Can I dive with dental implants?
Diving guidance is to wait until healing is complete, osseointegration has had adequate time, and the definitive restoration is fitted, since temporaries can loosen. The final prosthesis is typically made 4 to 6 months after placement. Once fully restored and healed, implants are not generally considered a barrier to diving.
Does a custom mouthpiece help with jaw pain from diving?
It may. Stock regulator mouthpieces are associated with more symptoms than custom fitted ones, and clenching to hold the mouthpiece in place is the identified risk factor for the jaw. A custom fitted mouthpiece lets you hold the regulator with less bite force.
Getting checked before a trip
If you have a dive trip coming up, a check-up with X-rays is the cheapest insurance available, because most of the causes of in-dive tooth pain are visible before you get in the water. The team at Lumi Dental sees patients Monday to Saturday at Melrose Park, with Sunday appointments by arrangement. New patients can find the current first visit offer on the current deals page.
This article is general information only and is not a substitute for personal dental or medical advice. Fitness to dive is a medical assessment, and any dental symptom experienced during a dive should be assessed before you go back in the water.
