A recent article by Dr. Gary DeWood, "Attack of the Collagen Eaters," created a very interesting discussion and led me to revisit my bonding checklist.
As discussed in the post, besides Chlorhexidine, application of a desensitizer - 5% Glutaraldehyde + 35% HEMA product like GLUMA (Heraeus) is highly effective in reducing post-op sensitivity. This is beneficial because of the following two actions.
I. Effect on bacteria
Glutaraldehyde is an antibacterial. It has an immediate affect, killing bacteria on the surface and also has long-term benefits preventing bacterial growth in micro gaps in dentin-resin interface.
II. Effect on Dentin structure
1. HEMA acts on the collagen of dentin as a cross-linking agent or flocculating agent increasing the strength and durability of resin-dentin bonds.
2. Glutaraldhyde + HEMA react with the dentinal fluid in the tubules and form a coagulation plug decreasing fluid movement in the tubules.
3. HEMA being very hydrophilic, acts as a re-wetting agent. In the case of etch-and-rinse bonding procedures, the re-wetting acts to expand the demineralized collagen and increase its surface energy, facilitating the diffusion of the hydrophilic resin monomer into the etched dentin.
So, what are the benefits of using a desensitizer?
1. Reduction of post-op sensitivity.
2. Antibacterial effect which helps mitigate bacterial growth and micro leakage at the restoration-tooth interface.
3. Improvement in the durability of the resin-dentin bond because of its affect on collagen of dentin.
4. "Re-wetting" improves the working of etch-and-rinse type bonding agents.
- G5 (Clinicians Choice)
- Microprime G (Danville Materials)
- Calm it (Dentsply Caluk)
Cobb DS, Reinhardt JW, Vargas MA. Effect of HEMA containing dentin desensitizers on shear bond strengths of a resin cement. Am J Dent 1997;10:62â5.
Macedo GV, Yamauchi M, Bedran-Russo AK. Effects of chemical cross-linkers on caries affected dentin bonding. J Dent Res 2009;88:1096â100.
Xu J, Stangel I, Butler IS, Gilson DF. An FT-Raman spectroscopic investigation of dentin and collagen surfaces modified by 2-hydroxyethylmethacrylate. J Dent Res 1997;76:596â601.