Root Caries Management
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Direct answer
Root caries is a disease of recession plus xerostomia: when the gingiva retreats, cementum sits in the plaque zone, and a dry mouth — most often the side effect of the antihypertensives, antidepressants and antihistamines that ageing patients take for granted — removes the saliva that would have buffered it. The lesion is a softened, yellowish or light-brown area at or below the cemento-enamel junction; a hard, dark, shiny lesion is arrested and needs no restoration. Management mirrors that distinction: prevention and remineralisation for active non-cavitated lesions, and restoration only when cavitation or function demands it — with glass ionomer the material of choice on root surfaces for its chemical bond to cementum and dentine and its fluoride release.
What you must remember
- Risk profile (viva favourite): age with recession, xerostomia from polypharmacy, poor plaque control, and dietary carbohydrate — the geriatric restorative triad, aggravated by radiotherapy and Sjögren syndrome.
- Active versus arrested: active root caries is soft or leathery, yellowish-light brown, often covered by plaque; arrested caries is hard, dark brown-black, shiny — leave the arrested lesion alone and manage its risk.
- Diagnosis: visual and tactile with a gentle probe at the CEJ; radiographs help where the lesion hides cervically, and bitewings of denture-bearing ridges are checked routinely.
- Non-cavitated management: fluoride — 5 percent sodium fluoride varnish applications at 3-6 month intervals for high-risk patients, and 5000 ppm fluoride dentifrice prescriptions — remineralise and harden the lesion.
- Material of choice: glass ionomer (conventional or resin-modified) bonds chemically to cementum and dentine, releases fluoride, tolerates moisture during setting — ideal on root surfaces where isolation is hard.
- When composite: aesthetic zones and moisture-controllable fields, with enamel bevelled where a margin lands on enamel and no bevel on cementum, which lacks the prism structure to etch.
- Saliva management: for xerostomic patients — sialagogues, frequent sips, alcohol-free chlorhexidine or saliva substitutes — because restoring without managing the dry mouth invites recurrence.
Managing a retired teacher's root lesions
A 68-year-old on two antihypertensives presents with recession and multiple cervical lesions: a soft, light-brown lesion at the mesiobuccal 13, a shallow hard black lesion at 34, and a cavitated leathery lesion at the 46 root surface carrying occlusal load. Three lesions, three rungs of the same ladder. The 13 lesion is active but non-cavitated: fluoride varnish now and at three months, 5000 ppm toothpaste prescribed, salivary substitutes discussed with the physician's awareness — no restoration. The 34 lesion is arrested: hard, dark, cleanable — photographed, documented, and left, with the patient taught that its colour is a scar, not an active disease. The 46 root lesion is cavitated, soft, and subject to masticatory load, so it is restored: rubber dam where the recession allows, carious cementum and dentine removed with a slow-speed round bur, and a resin-modified glass ionomer placed — chosen over composite because isolation at that cervical margin is imperfect and the chemical bond plus fluoride release serve a xerostomic mouth better. Recall is three-monthly with varnish, because the risk profile — recession, polypharmacy, dry mouth — is permanent even after the lesions are treated.
Where students slip
The classic error is restoring every discoloured root surface: cutting into an arrested lesion creates a cavity in cementum that never heals, and examiners present exactly this dark-but-hard case to catch the reflex. The viva trap is material justification — students name GIC for root caries but lose marks until they give the three reasons: chemical adhesion to cementum, fluoride release, and moisture tolerance during setting. Another documented confusion is bevel logic: enamel margins are bevelled, cementum margins are not, because etching does not create prism microporosity in cementum. The xerostomia question is the third standard probe — the answer expected is the polypharmacy link and saliva's buffering role, not a list of lozenges.
Frequently asked questions
Why is root caries common in elderly patients?
Gingival recession exposes cementum to plaque, and polypharmacy-induced xerostomia removes the saliva that buffers acid, combining exposure with reduced protection.
How is an arrested root caries lesion recognised?
It is hard, dark brown to black, and shiny — a remineralised scar that requires risk management and monitoring rather than restoration.
Why is glass ionomer preferred for root surface restorations?
It bonds chemically to cementum and dentine, releases fluoride locally, and tolerates the moisture that cervical margins rarely escape.
What fluoride regimens suit high-risk root caries patients?
5 percent sodium fluoride varnish at 3-6 monthly intervals with 5000 ppm prescription dentifrice for daily use, per current preventive guidance.
Should cementum margins be bevelled like enamel?
No — cementum lacks prismatic structure, so etching cannot create the microporosity a bevel exploits; enamel margins alone are bevelled.