Chlorhexidine increases the longevity of in vivo resin–dentin bonds

Abstract

The aim of this study was to evaluate the mechanical stability of resin-dentin bonds produced in vivo in the presence of chlorhexidine. Children presenting at least one pair of contralateral primary molars with occlusal carious lesions were enrolled in the study. After cavity preparation and phosphoric acid etching, dentin was treated with 5 microl of either 2% chlorhexidine (experimental group) or deionized water (control group) [corrected].Thirteen pairs of teeth were restored and were collected after physiological exfoliation. The periods in oral function after restoration were divided as follows: up to 30 d; and 1-5, 10-12, and 18-20 months. Beam-shaped specimens (0.81 mm(2)) were obtained and subjected to microtensile bond-strength testing. A significant decrease of the bond strength was observed in the control group starting at the 1-5 month period (30.6%), while in the experimental group this decrease started only after 10-12 months of function (26.3%). The use of chlorhexidine as an adjuvant to the adhesion to dentin did not produce any detrimental effect to the immediate bond strength and was capable of reducing the rate of resin-dentin bond degradation within the first few months after restoration.

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

“…In addition to minimizing the degradation of resin-dentin bonds, CHX application should not negatively influence the immediate bond strength, which has already been pointed out in literature (13,17). However, it is unclear in the literature the effect of CHX in caries-affected dentin (18)(19)(20), especially in primary teeth.…”

Bonding efficiency and durability: current possibilities

“…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. 88 Compared to control, aged CHX-treated dentin relates to higher bond strength values 73,74,77,78,79,80,89,90,91,92 which are interestingly equivalent to each other in most of the immediate evaluations. 93 Especially when two step etch-and-rinse adhesives are used, reduction of bond strength values for conventionally treated dentin over one to two years is of approximately 50%; when CHX is applied after acid etching, total reduction is around 20% 72 to 84.9%.…”

“…105 Remaining concentration then becomes no longer appropriate to exert noticeable antiproteolytic effects. 92 Usage of CHX on etched dentin before priming plus bonding together, thus when two-step etch-and-rinse adhesives are applied, 116 is strongly recommended; by the way, demineralization increases CHX binding to dentin. 67,106 Its effect on the durability of the bonding when three-step etch and-rinse are used, in turn, appears to be only slightly favorable.…”

“…115 Adversely, a limitation of CHX indication as an enzymatic inhibitor is that its effect seems not to be indefinitely long. 85 Because CHX molecule is large and water soluble, it may be gradually leached out from the adhesive interface, 92 especially when in contact with an external environment (through marginal gaps, for instance). 105 Remaining concentration then becomes no longer appropriate to exert noticeable antiproteolytic effects.…”

“…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.…”