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Localized mechanics of dentin self-etching adhesive system
Rodolfo Bruniera Anchieta1, Eduardo Passos Rocha, Ching-Chang Ko
1Dental School of Araçatuba, São Paulo State University, Araçatuba, SP, Brazil.
Journal of Applied Oral Science : Revista FOB
|December 18, 2008
Summary
The hybrid layer (HL) thickness significantly impacts stress distribution at the dentin-adhesive interface, especially under oblique loading. Thicker hybrid layers increase stress, while resin tag length has a minor effect.
Area of Science:
- Dental Materials Science
- Biomaterials Engineering
- Finite Element Analysis
Background:
- Composite resin bond strength to dentin relies on hybrid layer (HL) and resin tag (TAG) microstructure.
- Self-etching primer systems offer an alternative to etch-and-rinse protocols but HL thickness and TAG length can vary.
- Understanding interfacial stress distribution is crucial for optimizing adhesive performance.
Purpose of the Study:
- To investigate the localized stress distribution within the hybrid layer and at the dentin/adhesive interface.
- To evaluate the influence of hybrid layer thickness and resin tag length on stress distribution under different loading conditions.
Main Methods:
- Finite element (FE) analysis was employed using five 2D FE models simulating dentin restored with composite resin.
- Models varied in hybrid layer thickness (3 or 6 microm) and resin tag length (13 or 17 microm).
- Two loading conditions were simulated: perpendicular and oblique (25 degrees) with a 20N force.
Main Results:
- Peak von Mises and maximum principal stresses were higher under oblique loading compared to perpendicular loading.
- Hybrid layer thickness and resin tag microstructure did not affect stress under perpendicular loading.
- Decreasing hybrid layer thickness reduced stress under oblique loading; resin tag length primarily influenced peributular dentin stress.
- Hybrid layer thickness had a greater impact on stress than resin tag length.
- Peritubular dentin and adjacent structures experienced the highest stresses, particularly under oblique loading.
Conclusions:
- Hybrid layer thickness is a critical factor influencing stress distribution at the dentin-adhesive interface, especially under functional oblique loads.
- Resin tag length has a less significant role in stress dissipation compared to hybrid layer thickness.
- Optimizing hybrid layer formation is essential for enhancing the durability of composite resin restorations under occlusal forces.
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