Montgomery and Valid Consent in UK Dentistry: A Medico-Legal Reference

What the Montgomery standard actually requires

Before 2015, the adequacy of risk disclosure was judged by the Bolam test — essentially, "would a responsible body of clinicians have disclosed this?" Montgomery v Lanarkshire Health Board [2015] UKSC 11 replaced that test for information and risk disclosure with a patient-centred standard.

The duty, in the words the Supreme Court used, is that a clinician must take reasonable care to ensure that the patient is aware of any material risks involved in any recommended treatment, and of any reasonable alternative or variant treatments.

The test for whether a risk is material is twofold. The objective limb: would a reasonable person in the patient's position be likely to attach significance to the risk? And the subjective limb: is the clinician aware, or should the clinician reasonably be aware, that this particular patient would be likely to attach significance to it?

Two practical consequences follow. First, materiality is not a fixed percentage — a low-frequency risk can still be material if its consequences are severe or if it matters to this patient (for example, altered tongue sensation for a wind-instrument player, or any aesthetic risk for a patient whose occupation depends on appearance). Second, the standard is a dialogue, not a disclaimer: the patient must be given the opportunity to ask questions and the information must be comprehensible, not buried in a signed form.

The three elements of valid consent

For consent to be legally valid in the UK, all three of the following must be present. A signed consent form is evidence that a conversation happened — it is not consent in itself.

1. Capacity — the patient must be able to understand, retain, weigh and communicate the decision (Mental Capacity Act 2005 in England & Wales; equivalent frameworks in Scotland and Northern Ireland). Capacity is decision-specific and time-specific. For children, consider Gillick competence and the relevant age-of-consent rules.
2. Information — the patient has been told about the nature and purpose of the treatment, the material risks, the reasonable alternatives (including no treatment and its consequences), and the likely outcomes — to the Montgomery standard above.
3. Voluntariness — the decision is made freely, without coercion or undue influence from clinicians, family or financial pressure.

Consent is also a continuing process: it can be withdrawn at any time, should be revisited if the plan, the costs, the operator or the patient's circumstances change, and (for anything beyond simple, low-risk care) is best taken at a separate visit from the one at which treatment is carried out, so the patient has time to reflect.

What to document for consent

Good consent records are the single most effective medico-legal protection, because in a complaint or claim the question is rarely "did you treat well?" but "can you evidence what you discussed?" If it is not in the notes, it is very hard to prove it was said. FGDP/CGDent record-keeping guidance and defence organisations expect the consent conversation to be recorded contemporaneously. A defensible consent note should capture:

• The specific procedure discussed and its purpose / clinical justification (why this tooth, why now).
• The material risks discussed, named individually — not "risks explained". Record the ones relevant to this patient and procedure.
• The reasonable alternatives offered, including no treatment and its consequences.
• Expected outcomes, prognosis and any uncertainty, plus likely number of visits and after-care.
• Costs / NHS vs private status where relevant, and any plan or payment discussion.
• Patient-specific factors — questions the patient asked, concerns they raised, anything that made a particular risk material to them, and any information leaflets given.
• Confirmation that the patient had the opportunity to ask questions and that their understanding was checked.
• The decision and consent (and, for higher-risk or surgical care, a signed consent form and, ideally, a cooling-off period).
• Capacity / best-interests notes where relevant, and for children the basis of consent (parental responsibility / Gillick competence).

Material risks by procedure (quick reference)

The table below summarises the headline material risks and figures most commonly discussed for routine UK dental procedures, taken from the Nosht Consent Checklists dataset. These are prompts for discussion, not an exhaustive or patient-specific list. Tailor the conversation to the individual; the procedure sections beneath give the fuller lists.

Per-procedure material risks (the consent conversation)

The lists below mirror the Nosht Consent Checklists tool. They are discussion prompts — what a reasonable patient would commonly want to know — not a script, and not a substitute for tailoring to the individual.

Extraction (simple). Discuss: why the tooth cannot be saved; that it is done under local anaesthetic with forceps/elevators; post-op instructions (bite on gauze, soft diet, no rinsing for 24 hours); recovery (1–2 weeks for socket healing); replacement options (denture, bridge, implant, or accept the space); and the consequences of not extracting (infection, pain, spread). Material risks: pain; swelling; bleeding that may persist for several hours; dry socket (alveolar osteitis); nerve damage — numbness/tingling of lip, chin or tongue (lower teeth); oro-antral communication (upper premolars/molars); root fracture needing surgical retrieval; damage to adjacent teeth/restorations; socket infection. Reasonable alternatives: root canal treatment to retain the tooth; monitoring if symptom-free; specialist referral; no treatment.

Surgical extraction / wisdom tooth. Discuss: why a surgical approach is needed (impaction, angulation, root morphology); that it involves a flap, bone removal, sectioning and sutures; radiographic findings (proximity to the IAN canal / sinus); anaesthesia options (LA, LA with sedation, or GA); post-op regime; time off work/activities (2–5 days); suture removal if non-resorbable. Material risks: pain, swelling and bruising (may be significant for 5–7 days); inferior alveolar nerve (IAN) damage — numbness of lip and chin; permanent damage risk 0.5–2%; lingual nerve damage — numbness/altered taste of tongue; permanent damage risk 0.1–0.5%; numbness may be temporary (weeks–months) or permanent; bleeding; dry socket; jaw fracture (rare, higher risk in an atrophic mandible); trismus; infection requiring antibiotics; oro-antral communication (upper wisdom teeth); damage to adjacent teeth. Reasonable alternatives: monitoring with radiographic review if asymptomatic; coronectomy (deliberate root retention to protect the IAN); referral to oral surgery / maxillofacial; extraction under GA.

Root canal treatment. Discuss: the reason for RCT (irreversible pulpitis, necrotic pulp, periapical pathology); the procedure (access, cleaning, shaping, obturation); 1–3 visits depending on complexity; rubber dam isolation; that the tooth will usually need a crown/onlay afterwards; and the success rate (approximately 85–95% for primary RCT). Material risks: file fracture; root perforation; missed canal; treatment failure / persistent infection; need for retreatment, apicectomy or extraction; flare-up between visits; tooth fracture if not restored promptly with a crown; discolouration over time; sodium hypochlorite incident (rare but serious). Reasonable alternatives: extraction (± replacement); referral to an endodontist; pulp capping (if exposure is small and vital); no treatment (with risk of worsening infection, abscess, cellulitis).

Crown / bridge. Discuss: the reason and the preparation required; material options (PFM, zirconia, e.max, gold); typically 2 visits (preparation + fit); a temporary crown between visits; shade and aesthetics; longevity (average 10–15 years with good care); and that bridge abutment teeth require irreversible preparation. Material risks: post-op sensitivity; pulp death requiring root canal treatment (2–5% risk); shade mismatch; cement failure/debond; porcelain fracture; periodontal issues at margins; recurrent caries; abutment failure (bridges); bite adjustment at fit. Reasonable alternatives: direct composite; onlay/overlay (more conservative); removable partial denture; implant-supported restoration; resin-bonded (Maryland) bridge; accept the space.

Dentures (complete / partial). Discuss: the type (complete, partial acrylic or cobalt-chrome); the visits (impressions, bite registration, try-in, fit); the adaptation period; cleaning/maintenance; the need for review and reline; and realistic expectations. Material risks: initial speech changes; sore spots/ulceration; difficulty eating some foods; reline needed as bone resorbs; ongoing bone resorption; reduced taste (upper complete); gagging; looseness (esp. lower complete); increased caries/perio risk around clasps (partial); denture stomatitis. Adaptation over 4–8 weeks. Reasonable alternatives: implant-retained overdenture; fixed bridgework; implants with a fixed prosthesis; accept the spaces.

Dental implant. Discuss: suitability; the timeline (surgery, healing 3–6 months, restoration); possible bone graft/sinus lift; that smoking significantly reduces success; maintenance demands; cost/plan cover; and success rates (approximately 95% at 10 years). Material risks: nerve damage (IAN or mental nerve); sinus perforation (upper); failure to osseointegrate; peri-implantitis (infection and bone loss); bone-graft failure; post-op pain/swelling/bruising; bleeding; prosthetic complications (screw loosening, porcelain fracture); need for further surgery if it fails; damage to adjacent teeth. Reasonable alternatives: conventional fixed bridge; removable denture; resin-bonded bridge; accept the space.

Whitening / bleaching. Discuss: the type (home trays or in-office); pre-treatment assessment (caries, restorations, gingival health); that existing restorations will not whiten and may need replacing; realistic shade expectations; duration (home 2–4 weeks; in-office 1–2 sessions); and UK legal concentration limits — under the Cosmetic Products Enforcement Regulations 2013, products releasing >0.1% and up to 6% hydrogen peroxide may be supplied/used only by a dental professional, the first use must be by or under the supervision of a dentist, the patient must be 18 or over, and anything releasing >6% is illegal for cosmetic tooth whitening. Material risks: tooth sensitivity (may be significant); gingival irritation; uneven result; colour relapse over months to years; restoration mismatch; not effective on all discolouration (e.g. tetracycline, fluorosis); temporary increase in tooth porosity. Reasonable alternatives: composite bonding/veneers; porcelain veneers; microabrasion (surface staining); no treatment.

Orthodontics. Discuss: the appliance (fixed brackets, aligners, removable); duration (typically 12–24 months); any planned extractions; reviews every 4–8 weeks; that oral hygiene is critical (higher caries risk); long-term retainers; dietary restrictions; and cost. Material risks: root resorption; decalcification/white-spot lesions; relapse without retainer wear; TMJ issues; treatment longer than estimated; soft-tissue ulceration; bracket debonding; pulp devitalisation (rare); gingival recession; nickel allergy. Reasonable alternatives: accept current alignment; cosmetic bonding/veneers (camouflage); a different appliance type; surgical orthodontics (skeletal discrepancy).

Use the Nosht Consent Checklists tool

This page explains the standard and the material risks. To work through a consent conversation in clinic and produce a record, Nosht has a dedicated Consent Checklists tool: pick a procedure and work through four sections — discussion points, material risks, reasonable alternatives and expected outcomes — ticking items as you cover them, then copy a note-ready summary (with a Montgomery statement and an items-discussed count) straight into your clinical record. It covers 8 common procedures (simple and surgical extraction, RCT, crown/bridge, dentures, implant, whitening and orthodontics). The tool is a deterministic reference aide-mémoire: it works from a fixed UK consent dataset, stores nothing (state is in-memory only), and is not generated by a language model — the prompts and figures are fixed by design.

Nosht's separate note-writing features optionally use clinician-reviewed AI (Anthropic Claude Haiku 4.5) to help structure clinical notes from what you type; the clinical reference tools like Consent Checklists are deterministic and are not AI-generated. The checklist supports — it does not replace — the consent conversation: always tailor the discussion to the individual patient and document consent in your notes.

What is the Montgomery standard for consent in dentistry?

Montgomery v Lanarkshire Health Board [2015] UKSC 11 is the UK Supreme Court case that sets the standard for risk disclosure. It requires the clinician to take reasonable care to make the patient aware of any material risk of the recommended treatment and of any reasonable alternative. A risk is material if a reasonable person in the patient's position would attach significance to it, or if the clinician should reasonably be aware that this particular patient would. It is a patient-centred, dialogue-based standard that applies to dentistry as it does to medicine.

What makes dental consent valid?

Valid consent needs three things: capacity (the patient can understand, retain, weigh and communicate the decision), information (the nature and purpose of treatment, the material risks, the reasonable alternatives including no treatment, and the likely outcomes — to the Montgomery standard), and voluntariness (a free decision without coercion). It is a continuing process, can be withdrawn at any time, and must be documented. A signed form alone is evidence of consent, not consent itself.

What risks must I discuss before an extraction?

The commonly discussed material risks of a simple extraction are pain, swelling, bleeding that may persist for several hours, dry socket, nerve damage (numbness/tingling of lip, chin or tongue for lower teeth), oro-antral communication for upper premolars and molars, root fracture, damage to adjacent teeth and socket infection. For surgical or wisdom-tooth removal, also discuss trismus, jaw fracture (rare) and the nerve figures: IAN permanent damage risk around 0.5–2% and lingual nerve around 0.1–0.5%. Always include the reasonable alternatives (including coronectomy and no treatment) and tailor to the individual.

What should I document for consent?

Record the specific procedure and its purpose, the named material risks discussed, the reasonable alternatives offered (including no treatment), expected outcomes and prognosis, costs/NHS-vs-private where relevant, any patient-specific concerns or questions, confirmation the patient could ask questions and that understanding was checked, and the decision (with a signed form and cooling-off period for higher-risk or surgical care). The test: could a colleague reconstruct what the patient was told and why they agreed?

Is a signed consent form enough?

No. A signed form is evidence that a consent process took place, but it does not by itself prove the patient understood the material risks and alternatives. Valid consent is the conversation — capacity, adequate information to the Montgomery standard, and a voluntary decision — recorded in the clinical notes. For routine, low-risk care, a well-documented discussion is the core record; for surgical or higher-risk treatment, use a signed form and a contemporaneous note, ideally with time to reflect before treatment.

Do I need to mention rare risks?

Possibly, yes. Under Montgomery, frequency is not the deciding factor — a rare risk can still be material if its consequences are serious (for example permanent nerve damage) or if it matters to this particular patient. The duty is to disclose risks a reasonable person in the patient's position would attach significance to, and any the clinician should know this patient would. When in doubt, discuss it and document the discussion.