Effect of Chlorhexidine Pretreatment on Bond Strength Durability of Caries–affected Dentin Over 2-Year Aging in Artificial Saliva and Under Simulated Intrapulpal Pressure

Abstract

Pretreatment of caries-affected dentin with 5% chlorhexidine decelerates the bond strength loss over the long term. SUMMARYObjective: To evaluate the influence of 2% and 5% chlorhexidine (CHX) pretreatment on bond durability of a self-etching adhesive to normal (ND) and caries-affected (AD) dentin after 2-years of aging in artificial saliva and under simulated intrapulpal pressure (IPP).Methods: One hundred twenty freshly extracted carious teeth were ground to expose ND and AD. Specimens were distributed into three equal groups (n¼40) according to whether the dentin substrates were pretreated with 2% or 5% CHX or with water (control). Clearfil SE Bond (Kuraray) was applied to both substrates and composite cylinders (0.9 mm diameter and 0.7 mm height) were formed. Pretreatment and bonding were done while the specimens were subjected to 15 mm Hg IPP. After curing, specimens were aged in artificial saliva at 378C and under IPP at 20 mm Hg until being tested after 24 hours or 2 years (n¼20/group). Microshear bond strength was evaluated. Failure modes were determined using a scanning electron microscope (SEM) at 4003 magnification. Data were statistically analyzed using three-way analysis of variance (ANOVA); oneway ANOVA tests, and t-test (p,0.05). Additional specimens (n¼5/group) were prepared to evaluate interfacial silver precipitation.Results: For the 24-hour groups, there were no significant differences among the ND groups and AD groups. For ND aged specimens, the 5% CHX group had the highest value followed by the 2% CHX and control groups, although the difference was statistically insignificant. For AD aged specimens, the 5% CHX group revealed statistically higher bond values compared to the 2% CHX and control groups. Fracture modes were predominately adhesive and mixed. Different interfacial silver depositions were recorded.Conclusions: Two percent or 5% CHX pretreatment has no adverse effect on the 24-hour bonding to ND and AD. Five percent CHX was able to diminish the loss in bonding to AD after 2years of aging in artificial saliva and under simulated IPP.

Effect of chlorhexidine on the bond strength of a self-etch adhesive system to sound and demineralized dentin

“…Our results corroborate those of previous studies 9,10 reporting that disinfection did not adversely affect bonding to dentin compared with a control group. Nevertheless, these results do not agree with earlier reports showing decreased bond strengths when self-etch adhesive systems were applied after CHXbased cavity disinfectant.…”

“…6 However, the scientific literature reports conflicting results, since in vitro studies have demonstrated decreased bond strengths with self-etch adhesive systems applied after CHX-based cavity disinfectant, [7][8][9] while analysis of other data [9][10][11] demonstrated no adverse effect on dentin bonding compared with a control group. In the most commonly encountered clinical situations, especially when a cavity disinfectant is applied, bonding procedures are carried out in abnormal dentin, such as caries-affected dentin.…”

Bonding efficiency and durability: current possibilities

“…77,96,97,98,99 Higher bond strength durability of a two-step self-etch adhesive over 2-year aging in artificial saliva and under simulated intrapulpal pressure was also described in the literature when caries-affected dentin was pretreated with CHX. 100 Besides, the degradation of the adhesive interface in primary teeth may be counteracted or blocked by the application of CHX as a therapeutic primer. 92,101 Avoiding to add another step in the adhesive treatment of dentin, 6,88 some investigators have studied the beneficial effects of incorporation CHX into the etchant 83,84 or the adhesive.…”

Two-Year Interfacial Bond Durability and Nanoleakage of Repaired Silorane-Based Resin Composite

“…Output light intensity (!500 mW/cm 2 ) was periodically checked using an LED radiometer (Kerr Dental Specialties, West Collins Orange, CA, USA). The specimens were left to stand for 15 minutes and then were immersed in artificial saliva 17 for one month at 378C.…”