Antibacterial, chemical and physical properties of sealants with polyhexamethylene guanidine hydrochloride

Abstract

The aim of this study was to evaluate the influence of polyhexamethylene guanidine hydrochloride (PHMGH) in the physicochemical properties and antibacterial activity of an experimental resin sealant. An experimental resin sealant was formulated with 60 wt.% of bisphenol A glycol dimethacrylate and 40 wt.% of triethylene glycol dimethacrylate with a photoinitiator/co-initiator system. PHMGH was added at 0.5 (G 0.5%), 1 (G 1%), and 2 (G 2%) wt.% and one group remained without PHMGH, used as control (G CTRL). The resin sealants were analyzed for degree of conversion (DC), Knoop hardness (KHN), and softening in solvent (ΔKHN), ultimate tensile strength (UTS), contact angle (θ) with water or α-bromonaphthalene, surface free energy (SFE), and antibacterial activity against Streptococcus mutans for biofilm formation and planktonic bacteria. There was no significant difference for DC (p > 0.05). The initial Knoop hardness ranged from 17.30 (±0.50) to 19.50 (± 0.45), with lower value for G CTRL (p < 0.05). All groups presented lower KHN after immersion in solvent (p < 0.05). The ΔKHN ranged from 47.22 (± 4.30) to 57.22 (± 5.42)%, without significant difference (p > 0.05). The UTS ranged from 54.72 (± 11.05) MPa to 60.46 (± 6.50) MPa, with lower value for G 2% (p < 0.05). PHMGH groups presented no significant difference compared to G CTRL in θ (p > 0.05). G 2% showed no difference in SFE compared to G CTRL (p > 0.05). The groups with PHMGH presented antibacterial activity against biofilm and planktonic bacteria, with higher antibacterial activity for higher PHMGH incorporation (p < 0.05). PHMGH provided antibacterial activity for all resin sealant groups and the addition up to 1 wt.% showed reliable physico-chemical properties, maintaining the caries-protective effect of the resin sealant over time.

An effective method for preparation of high purity oligohexamethylene guanidine salts

“…Furthermore, the positive charge of the OHMG derivatives enables them to act as organic bases or form salts with various inorganic or organic acids such as hydrochlorides, hydrocyrates, hydrosalicylates, hydrosuccinates, etc. Especially the properties of the branched oligohexamethylene guanidine hydrochloride salt (OHMG-HC) have been earlier established [5,6], indicating its low toxicity and antibacterial activity against various bacteria and fungi [7]. Therefore, it has been used as an active base for dental gels [8] or for sprays to treat diseases of the oral cavity [9].…”

Myristyltrimethylammonium Bromide (MYTAB) as a Cationic Surface Agent to Inhibit Streptococcus mutans Grown over Dental Resins: An In Vitro Study

“…For the assessment of antibacterial property, discs of the polymerized dental resins entered into contact with an enriched broth containing S. mutans as previously performed [13,33,[40][41][42].…”

Antimicrobial Polymer−Based Assemblies: A Review

“…Figure 9 shows some chemical structures for cationic APs with sulfonium, phosphonium, or guanidinium as the cationic moiety. Besides the quaternary ammonium, cationic moieties in antimicrobial polymers could be sulfonium [139,140], guanidinium [125,128,141], or phosphonium [142,143]. Polymeric sulfonium salts exhibited high antibacterial activity against Gram−positive bacteria but were less active against Gram−negative bacteria [139].…”

“…Figure 9 shows some chemical structures for cationic APs with sulfonium, phosphonium, or guanidinium as the cationic moiety. From left to right, some cationic polymers with different cationic moieties such as sulfonium [139,140], phosphonium [142], and guanidinium [141,144].…”