“I Can Still Only Fit Two Fingers In”: Restricted Mouth Opening (Trismus) After Jaw Surgery
Summary
Almost everyone is stiff after jaw surgery, and for most people the mouth opens a little more each week. This guide is for people whose opening has stalled, gone backwards, or never come back the way they were told it would. It explains what trismus is, how recovery usually unfolds, the signs that need a same-day call, what your records should show, and when restricted opening might point to care that fell short.
Quick answer · updated November 2026
Restricted opening is expected in the first weeks after jaw surgery and usually improves over months, especially with guided exercises. If yours has stopped improving, is getting worse, or comes with fever, swelling or a changed bite, ask for it to be measured and the cause found. Ongoing restriction is not something you simply have to accept.
Your recovery at a glance
- 1The first two weeksSwelling peaks, opening is very limited, liquid or soft food only.
- 2Weeks two to sixSwelling settles, opening creeps up, exercises start when your surgeon says.
- 3Six weeks to three monthsSteady gains. Your opening should be measured, not guessed.
- 4Three to six monthsStill improving? Good. Stalled or worse? Ask why, and ask for a plan.
- 5Six months and beyondOngoing restriction deserves a proper review, physio and, if needed, imaging.
At any stage: fever, swelling that comes back, pus or a bad taste, a bite that suddenly feels wrong, or a jaw that locks needs a same-day call to your surgeon, or your nearest emergency department.
The kitchen bench was where I measured. Every Sunday night, after Mia was asleep, I'd stand at the bench, stack my fingers sideways and try to slide them between my front teeth. Two fingers. Then two fingers again. Sixteen weeks after my lower jaw was moved forward, it was still two fingers.
I'd cut grapes into quarters so I could get them in. I'd stopped eating with the blokes at work because I couldn't fit a sandwich in and I was sick of the jokes. My jaw ached by the afternoon, a tight, wooden ache just in front of my ears.
At the four-month review the surgeon looked in my mouth for about a minute. “It'll loosen up, mate. Everyone's stiff.” Nobody got out a ruler. Nobody mentioned a physio. I drove home thinking I must be doing something wrong, that I wasn't chewing enough gum or stretching hard enough.
What I wanted to know was simple. Is this normal? And if it isn't, who do I ask?
A composite story, drawn from the experiences of many families I have worked with, combined and changed so that no one can be identified. It does not describe any individual client.
If you are reading this late at night with a ruler or your own fingers in your mouth, I want you to know that the question you are asking is a reasonable one. Stiffness after jaw surgery is normal. Stiffness that stops improving, or that nobody measures or explains, is a different thing, and it deserves a proper answer.
This guide is for anyone who has had jaw surgery (orthognathic surgery, often called BSSO, Le Fort or double jaw surgery) and is still struggling to open their mouth. It is also for partners and parents watching someone they love eat through a gap the width of a straw. It covers what trismus is, how recovery usually goes, the warning signs, what to ask, what your records should show, and how the law looks at it.
Why I can write this
I have been a medical negligence lawyer since 2014 and have worked on many hundreds of claims, including many involving oral and maxillofacial surgery. My doctorate looked at patterns of failure in medical negligence. I am not medically qualified. The clinical facts in this article are checked against named sources, listed in the references, and I explain how I work in our editorial standards.
Start with your question
- How much should I be able to open my mouth after jaw surgery?
- How long does trismus last after jaw surgery?
- My opening has stopped improving. What could be causing it?
- When is restricted opening an emergency?
- What should I ask my surgeon at the next review?
- What should my records show?
- Could this be medical negligence?
- Is it too late to do anything about it?
What trismus is, and what “normal” opening looks like
Definition
Trismus is restricted opening of the mouth from any cause. The term was first used for the “lockjaw” of tetanus, but doctors and dentists now use it for any reduced jaw opening, including after surgery. Many clinicians describe an opening of less than about 35 millimetres as trismus, and a typical adult opening is roughly 40 to 60 millimetres.1
In plain terms: trismus means your mouth won't open as far as it should. It is a description of the problem, not an explanation of the cause.
Clinicians measure opening as the gap between your top and bottom front teeth when you open as wide as you comfortably can. You may see it written in your notes as MIO (maximal interincisal opening) or MMO (maximum mouth opening), with a number in millimetres. A number matters, because “a bit stiff” at three months and “a bit stiff” at nine months can mean very different things.
Many people use their fingers as a rough check at home, stacking them sideways between the front teeth. It's a useful way to notice change, but it is not a measurement. Finger widths vary. If you are worried, ask for a ruler measurement at every review and write it down.
Restricted opening matters because of what it does to an ordinary day: eating, brushing the back teeth, a dental check-up, yawning, kissing, singing, speaking clearly at work. Long-term restriction can also make future dental treatment harder. It is not a cosmetic complaint.
The first weeks: what's expected
Jaw surgery cuts and repositions bone, then holds it with plates and screws. The muscles that open and close your jaw are stretched, bruised and swollen. In the first days and weeks, being able to open only a little is expected. The Australian and New Zealand Association of Oral and Maxillofacial Surgeons lists “limited mouth opening requiring a soft diet” among the usual early effects, along with pain, swelling and fatigue.2 An NHS patient guide notes that most of the swelling goes within about a fortnight, while subtler swelling can take months.3
Research on how fast opening comes back is thinner than you might expect. A small 2022 pilot study measured opening before surgery and at two weeks, one month and three months. Opening dropped sharply in the first two weeks, then improved steadily over the three months that followed.4 That fits what most patients describe: a frightening start, then slow, real gains.
Weeks to months: when exercises and physio come in
Opening usually comes back with movement. Your surgeon or physiotherapist will tell you when to start jaw exercises, which might include gentle opening and closing, side-to-side movements, stretching with stacked tongue depressors, or a jaw-stretching device. Medical references describe stretching programmes, heat, and in stubborn cases physiotherapy and commercial stretching devices as standard approaches to trismus.1
Rehabilitation can make a real difference. In an older study that is still widely cited, researchers measured patients at least six months after jaw surgery, none of whom had a structured physiotherapy programme. People who had a sagittal split to move the lower jaw forward had lost, on average, about 29 per cent of their opening. The authors concluded that a structured post-operative rehabilitation programme was “critical”.5 Techniques have changed since then, but the lesson hasn't: opening needs a plan, not just time.
Definition
BSSO (bilateral sagittal split osteotomy) is the most common operation on the lower jaw. The surgeon splits the back of the jaw on each side lengthways so it can slide forward or back. Le Fort I is the common operation on the upper jaw. Doing both is often called bimaxillary or “double jaw” surgery.
In plain terms: these are the names you'll see on your operation report. They tell you which bones were moved, which helps explain where stiffness, numbness or joint problems might come from.
Questions to ask at your next review
- What is my opening today, in millimetres, and what was it last time?
- What opening would you expect me to have by now?
- Should I be seeing a physiotherapist, and can you refer me?
- What exercises should I be doing, how often, and for how long?
- If it's not improving, what do you think is causing it, and how will we find out?
- Do I need a scan?
- When should I worry, and who do I call out of hours?
When opening stalls or goes backwards
Most stiffness improves. When it doesn't, there is usually a reason, and finding it matters because the right treatment depends on the cause. Causes can include:
- Muscle stiffness and guarding that hasn't been worked through, sometimes because exercises weren't started, weren't explained, or hurt too much to keep up.
- Scar tissue in the muscles or soft tissues around the jaw.
- Infection, including infection around the plates and screws. An NHS consent guide notes that plates occasionally become infected and need to come out, usually months after surgery.3 A 2025 review of 29 studies estimated that plates or screws were removed because of infection in about 1.9 per cent of sagittal split operations.6
- Problems in the jaw joint (the temporomandibular joint, or TMJ), which can cause clicking, locking or pain in front of the ear. This series covers it in TMJ pain after jaw surgery.
- Bleeding or a haematoma in the muscles, and more general inflammation around the surgery.1
- Bone position or hardware problems, which may show up alongside a change in your bite. See “My bite has shifted”.
Only your treating team, with an examination and sometimes imaging, can work out which applies to you. What you can do is notice the pattern, write down the numbers, and keep asking until someone gives you an explanation that makes sense.
Expected, worth a review, or same-day help
This is a general guide only. If something feels wrong, trust that feeling and call. Your surgeon's own instructions come first.
Usually expected
- Very limited opening in the first two weeks
- Stiffness and aching that ease week by week
- A soft diet for some weeks
- Swelling that slowly goes down
In plain terms: uncomfortable, but heading in the right direction.
Ask for a review
- No improvement over several weeks
- Opening getting smaller after it had improved
- Clicking, catching or pain in front of the ear
- Exercises are too painful to do
- Nobody has measured your opening
In plain terms: not an emergency, but don't wait months for the next routine appointment.
Same-day help
- Fever or feeling unwell
- Swelling that returns or spreads
- Pus, discharge or a foul taste
- Your bite suddenly feels different
- Your jaw locks, or you can't swallow or breathe easily
In plain terms: call your surgeon now. If you can't reach them, go to an emergency department or call 000.
Fever with jaw restriction can signal infection, and restriction that doesn't improve, or is extreme, is a reason for referral to an oral and maxillofacial surgeon.1 If your opening has been restricted since surgery and you now also have new numbness, see “My lip and chin are still numb”, and for numbness after dental work generally, our guide to lower lip numbness and mental nerve injury.
Six months on: getting real answers
If you are six months or more past surgery and still restricted, you are entitled to more than reassurance. Reasonable next steps might include a measured examination, a referral to a physiotherapist with experience in jaw rehabilitation, imaging if the cause isn't clear, and a frank conversation about what is going on. You can also ask for a second opinion from another oral and maxillofacial surgeon. This series covers that in second opinions and revision jaw surgery.
Oral and maxillofacial surgeons in Australia hold qualifications in both medicine and dentistry, and the specialty is recognised by both the Dental Board and the Medical Board.7 You can check any practitioner's registration, and any conditions on it, on the Ahpra public register.8
If you feel brushed off, you are not imagining it, and you are not alone. Being told repeatedly that a real symptom is “normal” is something I write about in when being dismissed by a doctor becomes a legal issue.
It was the physio who got out the ruler. Nine months after surgery, on a GP referral I'd had to ask for myself. She measured, wrote “22 mm” on her pad, and looked at me for a second too long. “Has anyone measured this before?”
Nobody had. When I got my records, the review notes said “progressing well” three times. There was no number, no mention of exercises, and nothing about the hot, swollen patch I'd complained about at the six-week check. I sat at the same kitchen bench and read them twice.
My wife read them after me. She said, “You weren't doing it wrong. They just weren't looking.”
The physio sent a letter back to the surgeon asking for a scan. For the first time since the operation, someone had a plan. I still had a long way to go. But I stopped measuring alone on Sunday nights, and I stopped thinking it was my fault.
A composite story, drawn from the experiences of many families I have worked with, combined and changed so that no one can be identified. It does not describe any individual client.
What to look for in the records
Your records are often where the story becomes clear. You have a right to access your own health information. In NSW the Health Records and Information Privacy Act 2002 covers both public and private providers, and the Information and Privacy Commission explains how to ask.9 Our step-by-step guide to getting your medical records in Australia walks you through it.
| Record | Why it matters |
|---|---|
| Consent form and pre-operative information | Shows which risks were explained, including stiffness, infection, nerve injury and joint problems, and whether the conversation was more than a signature. |
| Operation report | Records which bones were cut and moved, how far, how they were fixed, and anything unexpected during surgery. |
| Discharge summary and instructions | Shows what you were told about diet, exercises, warning signs and follow-up. |
| Post-operative review notes | Should record your opening in millimetres at each visit. Repeated “progressing well” with no measurement is worth noticing. |
| Physiotherapy referral and notes | Shows whether rehabilitation was arranged, when, and how your opening changed. |
| Imaging and reports (OPG, CT, MRI) | Can show plate position, healing, joint changes or signs of infection. |
| Medication and antibiotic records | Can show whether infection was suspected and how it was treated. |
| Letters between surgeon, orthodontist and GP | Often contain the frankest account of what the team thought was happening. |
| Your own diary, photos and measurements | Your notes made at the time are evidence too. Keep them. |
How the law looks at it
Restricted opening after jaw surgery is not, on its own, negligence. Stiffness is a known part of recovery, and some people are left with restriction even after excellent care. The legal questions are about whether the care you received met the standard expected, and whether any shortfall made a real difference to you.
A claim usually turns on three questions: whether the care fell below what peers would widely accept as competent practice (section 5O of the Civil Liability Act 2002 (NSW))10, whether that shortfall probably caused harm you wouldn't otherwise have had (Tabet v Gett)11, and, where it matters, whether you were told the material risks first (Rogers v Whitaker)1213. Our guide to how a medical negligence claim works explains each one in plain terms.
In a trismus case, the questions might be: was your opening measured and monitored? Were exercises or physiotherapy arranged? Were signs of infection recognised and treated in time? Was a stalled recovery investigated?
In plain terms, the question is whether earlier or better care would probably have left you able to open further.
Queensland Health publishes a standard consent form specifically for orthognathic (corrective jaw) surgery, which shows how seriously the risks are taken.14 This series covers consent in “I didn't know that was a risk”.
Who can claim, and when
The person who had the surgery can claim. If they were under 18, a parent or guardian can usually act for them. Many people have jaw surgery in their late teens, and it's important to know that time limits for young people don't always wait until they turn 18. In NSW, time usually runs from when you knew, or ought to have known, enough to claim, not from the treatment itself, and courts can sometimes extend it, so an old injury may still count. See time limits in NSW or other states, and ask early.
More: complaint or claim? · how a claim is paid for · what a claim can cover
In my practice
When I read files about restricted opening after jaw surgery, I rarely find one dramatic mistake. I find a chain of small ones. A review note that says “progressing well” without a number. A second one the same. A patient who mentions a hot, swollen patch, and a note that doesn't record it. No physiotherapy referral, or one made months late. A bite that “feels a bit off” put down to swelling. Each link on its own can look minor. Together they can mean a problem that might have been caught at six weeks is found at nine months. What strikes me most is how often patients blame themselves. They think they didn't chew enough gum, didn't stretch hard enough, weren't brave enough. In the files, the gap is almost never effort. It is usually that nobody measured, nobody explained, and nobody followed up.
Both things can be true
Your surgeon may be skilled and caring, and your recovery may still have deserved closer attention. Stiffness may be a normal part of healing, and your restriction may still need answers. You can be grateful for parts of your care and still ask hard questions about others. Asking is not an accusation. It is how you get the information you need to move forward.
The bigger picture
The published evidence on how mouth opening recovers after jaw surgery is surprisingly limited. Some of the most cited work is decades old, and some recent studies involve only a handful of patients.45 In the United Kingdom, oral and maxillofacial surgeons and orthodontists have set up a national project collecting patients' own reports of their outcomes, with questionnaires before surgery, at four to eight weeks, and at one year.15 I am not aware of an equivalent national, patient-reported outcomes project for jaw surgery in Australia.
Here, oral and maxillofacial surgeons are regulated through Ahpra and both the Dental and Medical Boards.7 Complaints about care in NSW can go to the Health Care Complaints Commission.16 Paying for jaw surgery is its own maze. The professional association notes that Medicare rebates may be available for many procedures, but that private cover varies by policy.17 We cover this in Medicare, private health and jaw surgery in Australia.
Restricted opening also overlaps with other injuries on this site, including lingual nerve damage, loss of sensation in the lips, cheek, chin or tongue, neuropathic facial pain and permanent nerve damage after dental surgery.
Support
Living with a mouth that won't open can be isolating, painful and frightening. These services can help:
- Lifeline, 24-hour crisis support: 13 11 14 (listed on healthdirect's helplines page)18
- Beyond Blue, anxiety and depression support: 1300 22 4636
- Medicare Mental Health, help finding mental health support: 1800 595 212
- healthdirect, 24-hour nurse advice: 1800 022 222
- Health Care Complaints Commission (NSW): 1800 043 159
- Information and Privacy Commission NSW, help getting your health records: 1800 472 679
A man who measured alone at his kitchen bench every Sunday found someone who measured with him, and a plan. Whatever your number is tonight, you deserve the same.
With care,
Rosemary
Frequently asked questions
How long does trismus last after jaw surgery?
Opening is usually most limited in the first two weeks and improves over the following months, especially with exercises. If it has stopped improving or is getting worse, ask for it to be measured and the cause investigated.
How much should I be able to open my mouth after jaw surgery?
A typical adult opening is roughly 40 to 60 millimetres, and under about 35 millimetres is often described as trismus. What matters most is your own trend over time, measured in millimetres.
Is it normal to only fit two fingers after jaw surgery?
Early on, yes, it can be. Months later, especially if it isn't improving, it is a reason to ask for a measured review and a physiotherapy referral.
Can trismus after jaw surgery be permanent?
It can be, which is why early, structured rehabilitation and investigation of a stalled recovery matter. Ask your treating team what is causing yours and what can still be done.
Can I sue if I can't open my mouth after jaw surgery?
Restricted opening alone isn't negligence. A claim depends on whether your care fell below the accepted standard and whether that caused harm you wouldn't otherwise have had.
How long do I have to make a claim?
In NSW it is usually three years from when you knew, or ought to have known, enough to bring a claim, but exceptions apply and young people's time can run before 18. Ask early.
Questions about trismus after jaw surgery?
When you're ready, and not before, I can look at what happened and help you understand your options.
Jaw surgery: recovery, complications and your rights
- “Is it too late?” Time limits and what a jaw surgery claim can cover
- “I can still only fit two fingers in”: Restricted mouth opening (trismus) after jaw surgery (you are here)
- “Should my BSSO have been double jaw?” How surgeons plan BSSO vs bimax
- “Biggest mistake of my life”: Regret after jaw surgery
- “My lip and chin are still numb”: Nerve injury after jaw surgery
- “What will it cost?” Medicare, private health and jaw surgery in Australia
- “Nobody told me it would take this long”: Double jaw surgery recovery timeline
- “My bite has shifted”: Relapse after jaw surgery
- “The plate is poking through”: Infection and plates after jaw surgery
- “I didn't know that was a risk”: Consent before jaw surgery
- “My jaw clicks and locks now”: TMJ pain after jaw surgery
- “Do I need it redone?” Second opinions and revision jaw surgery
Part of our guide to oral, maxillofacial and dental negligence. Not sure where you stand? Try the free claim checker.
References
- Santiago-Rosado LM, Lewison CS. Trismus. StatPearls, NCBI Bookshelf. Updated October 2022.
- Australian and New Zealand Association of Oral and Maxillofacial Surgeons. Corrective jaw (orthognathic) surgery.
- Cambridge University Hospitals NHS Foundation Trust. Patient information and consent to jaw or chin corrective surgery (orthognathic surgery).
- Dinu C, Manea A, Tomoiagă D, et al. Recovery following orthognathic surgery procedures: a pilot study. Int J Environ Res Public Health. 2022;19(23):16028.
- Aragon SB, Van Sickels JE, Dolwick MF, Flanary CM. The effects of orthognathic surgery on mandibular range of motion. J Oral Maxillofac Surg. 1985;43(12):938–943.
- Kantzanou M, Kostares E, Koumaki V, et al. Prevalence of osteosynthesis hardware removal due to surgical site infections following sagittal split osteotomy: a systematic review and meta-analysis. J Clin Med. 2025;14(10):3558.
- Dental Board of Australia. Specialist registration.
- Australian Health Practitioner Regulation Agency. Register of practitioners.
- Information and Privacy Commission NSW. Fact sheet: Accessing your health information in NSW.
- Civil Liability Act 2002 (NSW) s 5O, Standard of care for professionals.
- Tabet v Gett [2010] HCA 12.
- Rogers v Whitaker [1992] HCA 58; (1992) 175 CLR 479.
- Australian Commission on Safety and Quality in Health Care. Informed consent.
- Queensland Health. Informed consent: maxillofacial (including the orthognathic (corrective jaw) surgery consent form).
- British Association of Oral and Maxillofacial Surgeons and British Orthodontic Society. Orthognathic PROMs project: patient information leaflet, version 2.0, January 2024.
- Health Care Complaints Commission NSW. Home page.
- Australian and New Zealand Association of Oral and Maxillofacial Surgeons. Medicare, private health insurance and your fees.
- healthdirect Australia. Mental health helplines.
Stories in this article are composites, drawn from the experiences of many families I have worked with, combined and changed so that no one can be identified. They do not describe any individual client.
Dr Rosemary Listing, PhD (Law), Medical negligence lawyer since 2014 · Of Counsel, Peter Evans & Associates. Rosemary's doctorate examined patterns of failure in medical negligence, and she teaches health law at the University of Newcastle. She is not medically qualified. About Rosemary.
Last updated: 10 November 2026 · First published: 10 November 2026 · Next review: May 2027
Cite this article: Listing R. “I can still only fit two fingers in”: Restricted mouth opening (trismus) after jaw surgery. Reframe Legal. Published 10 November 2026. https://reframelegal.com/trismus-after-jaw-surgery/
This article is general information, not legal or medical advice. It does not create a lawyer–client relationship. Speak to your treating clinicians about your health, and get legal advice about your own situation.
If you are in danger or need urgent medical help, call 000. For crisis support, call Lifeline on 13 11 14.
Legal services are provided by Peter Evans & Associates.
