Citation Information :
K Vallabhdas A, Kabbinale P, Nayak R, Rajakumari M, Shilpa T. Evaluation of Hybrid Layer and Bonding Interface after Water Storage with and without the Usage of 2% Chlorhexidine: A Scanning Electron Microscope Study. J Contemp Dent Pract 2018; 19 (1):52-59.
Aim: Restorative dentists employ different bonding systems
between the resin and the dentin and other dentinal tissues to
achieve the goal of micromechanical retention. Studies have
shown that the bond between composite and dentin degrades
over time because of the action of matrix metalloproteinases
(MMPs) on collagen fibrils left unprotected by acid etching. The
MMPs may be partially responsible for hybrid layer degradation.
Since chlorhexidine (CHX) inhibits MMPs, we hypothesized that
CHX would decelerate the loss of resin–dentin bonds. Hence,
this in vitro study is intended to evaluate the effects of 2% CHX
on hybrid layer and bonding interface.
Materials and methods: Totally, 40 freshly extracted molars
were randomly divided into four experimental groups. In all
40 specimens, class II cavities were prepared to a depth of
1 mm below the dentinoenamel junction with no axial wall, but
the elimination of the proximal enamel ridge. The teeth were
then randomly divided into four experimental groups, i.e.,
All Bond 2 without 2% CHX (group I), All Bond 2 with 2%
CHX (group II), One Coat 7.0 without 2% CHX (group III),
and One Coat 7.0 with 2% CHX (group IV). All the specimens
were derooted and sectioned mesiodistally into two halves
and placed under water at 37°C for 3 months and observed
under scanning electron microscope for the hybrid layer and
resin tag formation.
Results: Groups I and II showed statistically significant difference
when the presence/absence of resin tags was compared.
When groups III and IV were compared for the presence/absence of hybrid layer and resin tags, the results were statistically
Conclusion: Between all the four experimental groups, irrespective
of the bonding systems used, we concluded that groups
with 2% CHX usage showed promising results with presence/
absence of hybrid layer and resin tags formation.
Clinical significance: Studies suggest that the bond between
composite and dentin degrades over time because of the action
of MMPs on collagen fibrils left unprotected by acid etching.
Measures should be taken to prevent this from happening and
thus allow bond between composite and dentin last longer.
Carrilho MR, Tay FR, Donnelly AM, Agee KA, Tjäderhane L, Mazzoni A, Breschi L, Foulger S, Pashley DH. Host-derived loss of dentin matrix stiffness associated with solubilization of collagen. J Biomed Mater Res B Appl Biomater 2009 Jul;90(1):373-380
. Limitations in bonding to dentin and experimental strategies to prevent bond degradation. J Dent Res 2011 Aug;90(8):953-968
The role of host-derived dentinal matrix metalloproteinases in reducing dentin bonding of resin adhesives. Int J Oral Sci 2009 Dec;1(4):163-176
Effects of MMP inhibitors incorporated within dental adhesives. J Dent Res 2012 Jun;91(6):605-611
Effects of etch-and-rinse and self-etch adhesives on dentin MMP-2 and MMP-9. J Dent Res 2013 Jan;92(1):82-86
MMP inhibitors—a review. Int J Pharm Sci Health Care 2017 Mar-Apr;7(2):45-56
Substantivity of chlorhexidine to human dentin. Dent Mater 2010 Aug;26(8):779-785
Collagen degradation by host-derived enzymes during aging. J Dent Res 2004 Mar;83(3):216-221
Use of a specific MMP-inhibitor (galardin) for preservation of hybrid layer. Dent Mater 2010 Jun;26(6):571-578
In vitro degradation of resin-dentin bonds analyzed by microtensile bond test, scanning and transmission electron microscopy. Biomaterials 2003 Sep;24(21):3795-3803
Review of matrix metalloproteinases’ effect on the hybrid dentin bond layer stability and chlorhexidine clinical use to prevent bond failure. Open Dent J 2010 Jul;4:147-152
Effect of 2% chlorhexidine on microtensile bond strength of composite to dentin. J Adhes Dent 2003 Summer;5(2):129-138
SEM analysis of hybrid layer and bonding interface after chlorhexidine use. Oper Dent 2012 Mar-Apr;37(2):172-180
Dentine permeability and dentine adhesion. J Dent 1997 Sep;25(5):355-372
Reactivation of inactivated endogenous proteolytic activities in phosphoric acid-etched dentine by etch-and-rinse adhesives. Biomaterials 2006 Sep;27(25):4470-4476
Optimizing dentin bond durability: Control of collagen degradation by matrix metalloproteinases and cysteine cathepsins. Dent Mater 2013 Jan;29(1):116-135
Inhibition of the activities of matrix metalloproteinases 2, 8, and 9 by chlorhexidine. Clin Diagn Lab Immunol 1999 May;6(3):437-439
et al. In vivo preservation of the hybrid layer by chlorhexidine. J Dent Res 2007 Jun;86(6):529-533
Chlorhexidine stabilizes the adhesive interface: a 2-year in vitro study. Dent Mater 2010 Apr;26(4):320-325
In vivo chlorhexidine stabilization of hybrid layers of an acetone-based dentin adhesive. Oper Dent 2009 Jul-Aug;34(4):379-383
Effect of 2% chlorhexidine digluconate on the bond strength to normal versus cariesaffected dentin. Oper Dent 2009 Mar-Apr;34(2):157-165
Influence of chlorhexidine digluconate concentration and application time on resin-dentin bond strength durability. Eur J Oral Sci 2009 Oct;117(5):587-596
Effect of chlorhexidine on the 18-month clinical performance of two adhesives. J Adhes Dent 2013 Jun;15(3): 287-292.