Elastic Recovery — MFDS Part 1 MCQ

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ModerateDental MaterialsElastic RecoveryMFDS Part 1

During laboratory testing of a set elastomeric impression material, a specimen is subjected to a defined deformation. The load is then removed, and the proportion of that deformation reversed after a specified interval is calculated. Which property is being assessed?

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Correct answer: E — Elastic recovery

The correct answer is E, elastic recovery. It describes the extent to which an impression material returns towards its original dimensions after an applied deformation is removed. High elastic recovery reduces distortion when a set impression is withdrawn past undercuts. Plastic deformation is irreversible deformation. Creep is progressive, time-dependent deformation while a load remains applied. Permanent set is the residual deformation left after unloading and is therefore inversely related to elastic recovery. Compression set is the residual deformation specifically following prolonged compressive strain, rather than the proportion of deformation reversed. Elastic recovery is commonly determined by applying a defined strain and measuring the dimensional recovery after unloading.

Reference: Singer L, et al. Evaluation of the properties of a new super quick-setting (2 min) polyether impression material. Clinical Oral Investigations. 2023. https://pubmed.ncbi.nlm.nih.gov/37017760/