Epigallocatechin-3-gallate and Epigallocatechin-3-O-(3-O-methyl)-gallate Enhance the Bonding Stability of an Etch-and-Rinse Adhesive to Dentin

Abstract

This study evaluated epigallocatechin-3-gallate (EGCG) and epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG-3Me) modified etch-and-rinse adhesives (Single Bond 2, SB 2) for their antibacterial effect and bonding stability to dentin. EGCG-3Me was isolated and purified with column chromatography and preparative high performance liquid chromatography. EGCG and EGCG-3Me were incorporated separately into the adhesive SB 2 at concentrations of 200, 400, and 600 µg/mL. The effect of cured adhesives on the growth of Streptococcus mutans (S. mutans) was determined with scanning electron microscopy and confocal laser scanning microscopy; the biofilm of bacteria was further quantified via optical density 600 values. The inhibition of EGCG and EGCG-3Me on dentin-originated collagen proteases activities was evaluated with a proteases fluorometric assay kit. The degree of conversion (DC) of the adhesives was tested with micro-Raman spectrum. The immediate and post-thermocycling (5000 cycles) bond strength was assessed through Microtensile Bond Strength (MTBS) test. Cured EGCG/EGCG-3Me modified adhesives inhibit the growth of S. mutans in a concentration-dependent manner. The immediate MTBS of SB 2 was not compromised by EGCG/EGCG-3Me modification. EGCG/EGCG-3Me modified adhesive had higher MTBS than SB 2 after thermocycling, showing no correlation with concentration. The DC of the adhesive system was affected depending on the concentration of EGCG/EGCG-3Me and the depth of the hybrid layer. EGCG/EGCG-3Me modified adhesives could inhibit S. mutans adhesion to dentin–resin interface, and maintain the bonding stability. The adhesive modified with 400 µg/mL EGCG-3Me showed antibacterial effect and enhanced bonding stability without affect the DC of adhesive.

Adhesive systems modified with antimicrobial agents: a literature review

“…37,38 The basic components of the adhesive system are: conditioning agent, primer and adhesive, in addition to photo initiators, polymerization inhibitors, and inorganic fillers. 33 They can also be modified with antimicrobial agents, [1][2][3][4][5][6][7][8][9][10][11][12][15][16][17][18][19][20]22,24,26,[28][29][30][31][39][40][41][42][43][44] mineralizing agents, 2,3,16,22,26,30,45 protein repellent, 2 inhibitors of metalloproteinases, 6,46,47 and even inti-inflammatory agents. 5 The understanding of the function of each system component and their careful use, respecting their indications, will be essential for adhesion success.…”

“…2,4,9,16,18,19,52,53 One mechanism by which caries can affect the durability of restorations is related to biofilm accumulation on resinous restorative materials. 8,16,52 Therefore, the microbial colonization begins from the acquired film (protein layer from the saliva), forming the oral biofilm. 2,52 The bacteria use dietary carbohydrates for their metabolism and produce acids that lead to pH reduction and teeth demineralization.…”

“…9,52 Many researchers develop new antimicrobial adhesives, or modify the materials available in the market with the addition of antimicrobial agents as a resort to secondary caries inhibiting mechanisms. [1][2][3][4][5][6][7][8][9][10][11][12][15][16][17][18][19][20]22,24,26,[28][29][30][31][39][40][41][42][43][44] Thus, the addition of benefit with potential to increase restoration longevity is desired. 16,52 In this context, nanotechnology has been used in caries prevention.…”

“…Secondary caries leads to restoration failure. [1][2][3][4][5][6][7][8][9][10] In the oral environment, the restorative composite u ndergoe s poly mer i zat ion sh r i n k age, 9,11-1 4 receives masticatory loads, 10,15 and accumulates biofilm; 8,16 being, therefore, susceptible to marginal failure, 10,12,17,18 adhesive interface degradation, 6,8,10,15,17 and micro-infiltration. 1,10,13,15,19 Likewise, residual bacteria may remain after cavity preparation, thus inducing the formation of recurrent caries.…”

Avaliação do efeito antibacteriano e da citotoxicidade de um adesivo com nanopartículas de prata e sua resistência de união à dentina associado ao uso de nanopartículas de hidroxiapatita

“…Dentre os materiais restauradores de uso direto, a resina composta é aquele que mais acumula biofilme (3,4,24,26,36,44), a adesão inicial desses microorganismos ocorre após a deposição da camada de proteínas que está associada a forças Van de Waals e eletrostáticas (42). Assim, estudos sugerem que quanto maior a energia livre e maior hidrofilia do material, maior a adesão microorganismos (8,42).…”