Restorative & Materials · patient case question
In a deep Class V preparation, which material is placed LAST?
Patient case: Cervical lesions in a care-home resident
Patient: Male, 84 years old
Chief Complaint: Brought by his caregiver — “His teeth are wearing away at the gumline.”
Background: Lives in residential care with an all-day caregiver. Mild cognitive impairment; cooperates for short appointments only. Takes four medications, three of them anticholinergic. Limited manual dexterity.
Vital Signs: BP 142/80 mmHg · HR 70 bpm
Findings: Generalised recession with multiple soft, leathery root-surface Class V lesions across all quadrants. Markedly reduced salivary flow. Isolation is difficult and he cannot tolerate rubber dam or long appointments.
Show answer and explanation
Correct answer: D. The definitive restorative material
- A. The bonding agent is the last step BEFORE the restorative material — applied to conditioned enamel and dentine and light cured. But the restorative material still goes on top of it, which is what the question asks.
- B. Calcium hydroxide goes FIRST, and only over the deepest area closest to the pulp. It is placed as a thin liner and must then be covered, because it is soluble and mechanically weak.
- C. A base sits over the liner and beneath the restorative material, replacing missing dentine bulk and providing thermal insulation where the remaining dentine is thin.
- D. CORRECT. The DEFINITIVE RESTORATIVE MATERIAL is always placed last, over everything beneath it. The sequence runs from the pulp outward: LINER (calcium hydroxide or a calcium silicate, only over the deepest dentine) → BASE if bulk replacement or insulation is needed → ADHESIVE, meaning etch, prime and bond → RESTORATIVE MATERIAL. Each layer protects and is covered by the next.
Note: Liners and bases are used far more sparingly now than in traditional teaching. Current practice restricts calcium hydroxide or a calcium silicate to a genuine or very near pulp exposure; over the rest of the preparation the ADHESIVE itself serves as the liner, and placing unnecessary bulk beneath a restoration simply reduces the bonded tooth surface available.
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