Generalised erosion with jaw pain, and a dentist proposing 4 mm of bite opening
A 33-year-old woman is referred for full-mouth rehabilitation of generalised tooth wear. Her general dentist has proposed 'full-mouth crowns with the bite opened 4 mm'. She has gastro-oesophageal reflux, was treated for bulimia six years ago, and reports cold sensitivity and difficulty eating. She also reports morning preauricular pain, jaw tightness and occasional headaches, and takes a selective serotonin reuptake inhibitor. Examination shows a maximum opening of 34 mm with 2 mm deviation to the right, no click and no history of locking; bilateral masseter and temporalis tenderness; the temporomandibular joints are not tender and there is no swelling. There is 4 mm of occlusal vertical dimension loss with cupping of the posterior teeth, exposed dentine and near-complete loss of anterior guidance. Twenty-eight teeth are present, none mobile, with no periapical pathology. She is anxious about irreversible treatment and asks directly whether her jaw pain is caused by her bite.
1. What is the diagnosis of her jaw pain, and how does it affect the timing of any prosthodontic treatment?
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Diagnosis
The picture fits myofascial pain rather than a joint problem:
- Bilateral, diffuse tenderness of masseter and temporalis, worst in the morning - typical of clenching.
- Limited opening with deviation but no click, no locking, no joint tenderness and no swelling - against disc displacement or arthropathy.
- A selective serotonin reuptake inhibitor is associated with sleep bruxism as a recognised adverse effect.
Answering her question directly
There is no good evidence that occlusal factors cause temporomandibular disorders, and irreversible occlusal treatment is not an appropriate first-line treatment. Tell her that honestly: her bite is not the cause, and her pain is not a reason to rush crowns.
Management before prosthodontics
- Education, self-care, soft diet, short-term NSAIDs, thermotherapy, jaw exercises and sleep hygiene.
- A hard, full-arch stabilisation splint with even contacts in centric relation and guidance distributed in excursions.
- Ask her physician to review the SSRI, since that is a medical decision, not yours.
- Reassess in four to six weeks.
Why this matters for the plan
Starting irreversible crown work on a patient with untreated myofascial pain means that any subsequent pain is attributed to the restorations and the dentist cannot disentangle the two. Reversible treatment first, then reassess. In most cases the symptoms settle and the rehabilitation can proceed.
2. Is a 4 mm increase in occlusal vertical dimension reasonable here, and how would you test it before committing to it?
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Is it reasonable?
A freeway space of 2-4 mm is usual, so a 4 mm increase takes her towards the upper limit of comfortable opening; increases beyond about 5 mm are poorly tolerated (speech, swallowing, aesthetics, muscle fatigue). She has genuine indications - 4 mm of wear, lost anterior guidance, dentine exposure - so some opening is justified. But the number should be determined by aesthetics, phonetics and the wax-up, not fixed in advance by her dentist.
Testing it reversibly
- Diagnostic wax-up at the proposed vertical dimension, then either a full-arch hard splint worn at that dimension or, better, provisional restorations.
- Wear the trial for at least three months, and judge it on comfort, speech, appearance, swallowing, muscle symptoms and whether a stable, repeatable centric relation can be recorded.
- If symptoms worsen or speech is affected, reduce the opening rather than persist.
The trap in this case
Her erosion is active. Restoring eroded palatal and occlusal surfaces while reflux continues means the margins will be exposed and the restorations will fail. Control the acid first - medical management of reflux, dietary advice, no brushing immediately after reflux, and fluoride - and confirm with her physician that the reflux is controlled before starting definitive work.
Note on evidence
Opening the bite is not a treatment for temporomandibular disorders; it is a treatment for tooth wear. Sound reasoning should keep those two claims separate.
3. Outline the final rehabilitation plan: sequence, occlusal scheme and material choices.
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Sequence
- Disease control: reflux management, dietary and hygiene advice, fluoride, caries removal, periodontal treatment, and splint therapy with reassessment of the myofascial pain.
- Trial vertical dimension: wax-up, then either a splint at the proposed dimension or, preferably, adhesive provisional restorations worn for about three months.
- Provisional phase: full arch, allowing aesthetics, phonetics and occlusal scheme to be tested before anything is irreversible.
- Definitive restorations in a planned order, starting in the arch and segment where the trial was most successful, keeping posterior support and anterior guidance consistent throughout.
- Night guard and a maintenance programme, because erosion and bruxism are lifelong.
Occlusal scheme
Mutually protected: maximum contacts on posterior teeth in centric relation, with immediate anterior and canine guidance in excursions and no non-working interferences. Centric relation must be recorded, not assumed.
Materials
- Anterior and premolar: lithium disilicate bonded where enamel permits; monolithic or minimally layered zirconia if parafunction dominates.
- Posterior: monolithic zirconia or cast metal for wear resistance.
- Consider additive or direct composite first in the most eroded areas - it is cheaper, reversible and tests the vertical dimension before committing to a full-mouth reconstruction.
Consent
Explain that the restorations do not cure the reflux or the bruxism, that long-term survival depends on the guard and on acid control, and record that alternatives including continued monitoring were discussed.