Polymerization shrinkage stress of composite resins and resin cements - What do we need to know?
Level 5 - mechanism / opinion, no new human data
Narrative review of bench and clinical literature without systematic review methodology
PubMed 28902242 · doi:10.1590/1807-3107BOR-2017.vol31.0062
What was done
This narrative review synthesizes literature concerning polymerization shrinkage and shrinkage stress generation in composite resins and resin cements. It examines stress development mechanisms, laboratory research methodologies, contributing material factors, clinical consequences (including cusp deflection, bond degradation, and marginal gaps), clinical mitigation techniques, and developments in low-shrinkage dental materials.
What was found
No quantitative findings, sample sizes, or numerical effect sizes are reported in the abstract. Polymerization shrinkage stress is reported to associate with enamel crack propagation, cusp deflection, marginal and internal gaps, decreased bond strength, post-operative sensitivity, and marginal staining. The authors report an absence of strong evidence directly relating polymerization shrinkage to secondary caries or posterior tooth fracture, though an indirect relationship exists with composite and resin-bonded ceramic restoration longevity.
Why it matters
The paper contextualizes the clinical relevance of laboratory-measured shrinkage stress, cautioning that while stress causes marginal defects and sensitivity, direct links to secondary caries and tooth fracture lack robust evidence.
Limits
As a narrative review, it lacks a systematic search protocol, predefined inclusion criteria, quality appraisal, and meta-analytic synthesis. No quantitative comparison between material formulations or placement techniques is provided in the abstract.
Cited by
- supports Light curing large resin fillings creates shrinkage stress that exerts tensile force on the tooth and causes postoperative sensitivity and microfractures.