Chlorhexidine-containing Acid Conditioner Preserves the Longevity of Resin-dentin Bonds

Abstract

SUMMARYThe current study evaluated the effect of 2% chlorhexidine digluconate (CHX) on the immediate and six-month resin-dentin bond strength (BS) and nanoleakage pattern (NL) of etch-andrinse adhesives when applied in aqueous or associated to the phosphoric acid conditioner. The occlusal enamel of 42 caries-free extracted molars was removed in order to expose a flat dentin surface. In groups 1 and 2 (control-C), the surfaces were acid etched with conventional phosphoric acid, and the adhesives Prime&Bond NT (PB) and Adper Single Bond 2 (SB) were applied after rinsing, drying and rewetting with water. In groups 3 and 4 (Ac/CHX), the adhesives were applied in a similar manner, however, a 2% CHX-containing acid was previously applied. In groups 5 and 6 (CHX), the adhesives were applied according to the control group; however, the rewetting procedure was performed with an aqueous solution of 2% CHX for 60 seconds. Composite buildups (Opallis, FGM) were constructed incrementally, and the specimens were longitudinally sectioned in the "x" and "y" directions to obtain bonded sticks (0.8 mm 2 ) to be tested in tension at 0.5 mm/minute immediately or after six months of water storage. For NL, two bonded sticks from each tooth were coated with nail varnish, placed in silver nitrate and polished down with SiC paper. Resin-dentin interfaces Clinical RelevanceThe addition of CHX digluconate in the acidic conditioner may be an excellent tool to increase the stability of collagen fibrils within the hybrid layer against host-derived metaloproteinases without the need for additional steps for the bonding protocol. 482Operative Dentistry were analyzed by EDX-SEM. The BS and NL data from each adhesive was submitted to two-way repeated measures ANOVA and Tukey's test (α α=0.05). After six months of water storage, significant reductions in BS were observed for both adhesives in the control group (p<0.05). When Ac/CHX or CHX was used, no significant reductions in BS were observed for both systems. Nanoleakage was more evident in the control group than in the experimental groups (p<0.05), even after six months. The use of CHX in an aqueous solution or associated with the acid conditioner was effective for reducing degradation of resin-dentin bonds after six months of water storage.

Influence of chlorhexidine application on longitudinal adhesive bond strength in deciduous teeth

“…7,8,12,13,16 The chlorhexidine application showed no interference on immediate bond strength but resulted in higher bond strength values than the control group after 6 months, even when the chlorhexidine application time was reduced to 30 seconds.…”

“…[7][8][9][10][11] In a few studies, researchers attempted to reduce this time to save both the professional's and the patient's time. 10,[12][13][14] However, none of these studies evaluated the reduced time of chlorhexidine application on the dentin of deciduous teeth.…”

Chlorhexidine does not increase immediate bond strength of etch-and-rinse adhesive to caries-affected dentin of primary and permanent teeth

“…Previous studies (13,24) have shown that caries-affected dentin applying the 2% CHX after acid etching, in order to minimize the degradation of resin-dentin bonds, does not negatively influence the immediate bond strength to sound permanent dentin. Similar results were observed in the present study in primary teeth, corroborating the findings of Ricci et al (17).…”

Bonding efficiency and durability: current possibilities

“…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. 87,97,102,103,104 First strategy was alleged to reduce the effectiveness of CHX in the inhibition of MMPs and CCs, due to the limited contact time and the little concentration of CHX at the moment of adhesive application.…”

“…76 CHX was accordingly shown to partially conserve the integrity of the hybrid layer, 77 , favoring bond durability. CHX can be used as an antiproteolytic "primer" solution directly applied on the dentin surface, or after phosphoric acid etching and rinsing 74,78,79,80,81,82 or incorporated into the acid etching agent 83,84 or within the adhesive system composition. 74,85,86,87 The use of 2% CHX solution as an effective and nonspecific protease inhibitor primer, after acid-etching, is attractive from a clinical point of view, since it is already used in other oral health situations as an antimicrobial agent.…”