Zinc–Calcium–Fluoride Bioglass-Based Innovative Multifunctional Dental Adhesive with Thick Adhesive Resin Film Thickness

Abstract

Apart from producing high bond strength to tooth enamel and dentin, a dental adhesive with bio-therapeutic potential is clinically desirable, aiming to further improve tooth-restoration longevity. In this laboratory study, an experimental two-step universal adhesive, being referred to as Exp_2UA, applicable in both etch-and-rinse (E&R) and self-etch (SE) mode and combining a primer, containing 10-methacryloyloxydecyldihydrogen phosphate (10-MDP) as functional monomer with chemical binding potential to hydroxyapatite, with a bioglass-containing hydrophobic adhesive resin, was multifactorially investigated. In addition to primary property assessment, including measurement of bond strength, water sorption, solubility and polymerization efficiency, the resultant adhesivedentin interface was characterized by TEM, the filler composition analyzed by EDS and the adhesive's bioactive potential estimated by measuring long-term ion release and assessing its anti-enzymatic and anti-bacterial potential. Four representative commercial adhesives served as reference/controls. Application in both E&R and SE mode resulted in durable bonding performance to dentin, as evidenced by favorable 1-year aged bond-strength data and a tight interfacial ultra-structure that, as examined by TEM, remained ultra-morphologically unaltered upon 1-year water-storage aging. TEM revealed a 20-µm thick hydrophobic adhesive layer with a homogeneous bioglass filler distribution. Adequate polymerization conversion resulted in extremely low water sorption and solubility. In-situ zymography revealed reduced endogenous proteolytic activity, while Streptococcus mutans biofilm formation was inhibited. In conclusion, the three/two-step E&R/SE Exp_2UA combines high bonding potential and bond-degradation resistance with long-term ion release rendering the adhesive anti-enzymatic and anti-bacterial potential.

Nanoindentation Mapping and Bond Strength Study of Adhesive–Dentin Interfaces

“…Nevertheless, the term “transition” is valid as both the nano‐elastic modulus and nanohardness gradually increase from the hybrid layer towards unaffected dentin. The bottom of the hybrid layer could be considered as the weakest area across the adhesive interface, [ 26 ] as resin is there expected to have least effectively infiltrated and enveloped exposed collagen, in particular when an E&R adhesive is used or one of the newest generations of “universal” adhesives is applied in E&R mode. Such incomplete resin infiltration has indeed been documented to have resulted in a discrepancy between dentin demineralization and resin infiltration.…”

“…is the most common filler adding in the adhesive, while bioglass filler is sometimes added to fortify bioactive efficacy. [ 1,26,46 ] Nevertheless, whether the filled adhesive is more beneficial to mechanical characteristics and clinical bonding performance than the unfilled one, still needs to be established.…”

Physicochemical Effects of Niobic Acid Addition Into Dental Adhesives

“…Dental adhesives have been modified to present superior therapeutic and physicochemical properties (Profeta, 2014;Balbinot et al, 2020a;Bendary et al, 2020;Garcia et al, 2020b;Yao et al, 2020). In this context, bioactive fillers have been incorporated into dental adhesives (Profeta, 2014;Balbinot et al, 2020a;Bendary et al, 2020;Braga and Fronza, 2020;Yao et al, 2020). However, the effect of these fillers in the physicochemical properties of resin-based materials must be addressed to guarantee the proper behavior for dental adhesives.…”

“…Bioactive particles have been used to assist in tooth remineralization (Balhaddad et al, 2019;Braga and Fronza, 2020), making bioactive resinbased dental materials to be feasible approaches to prevent dental demineralization and to provide the recovery of hard dental tissues affected by caries (Garcia et al, 2017;Ibrahim et al, 2020a;Ibrahim et al, 2020b). Calcium phosphates (Garcia et al, 2017;Braga and Fronza, 2020), calcium silicates (Profeta, 2014), bioactive glasses (Balbinot et al, 2020a;Yao et al, 2020), and zincbased particles (Toledano et al, 2016) were already tested and showed mineral deposition or remineralization effect on dental hard tissues. Recently, niobium-based particles have been highlighted due to their interesting properties for dentistry, such as high radiopacity and bioactivity (Marins et al, 2018).…”

Assessment of Zinc-Bound Phosphate-Based Glass-Coated Denture-Relining Material with Antifungal Efficacy for Inhibiting Denture Stomatitis

“…Therefore, this discrepancy in the role of zinc has induced the use of zinc-doped phosphate-based glasses (Zn-PBGs) as independent controlled delivery agents, which have been reported to remain stable and effective for long-term use. Bioglass-based materials, including phosphate-based or phosphate-containing glasses, have also been used in this context [ 26 ]. The primary advantage of these materials is their negligible cytotoxicity.…”