Synthesis and characterization of novel halloysite-incorporated adhesive resins.
OBJECTIVE
To investigate the effects of Halloysite® aluminosilicate clay nanotubes (HNTs) addition on selected physical, mechanical, and biological properties of experimental adhesive resins.


METHODS
Experimental dentin adhesive resins were prepared by mixing Bis-GMA, TEGDMA, HEMA (50/25/25wt.%), and photo-initiators. As-received HNTs were then incorporated into the resin mixture at distinct concentrations: 0 (HNT-free, control), 1, 2.5, 5, 7.5, 10, and 20wt.%. The degree of conversion (DC), radiopacity (RP), Knoop hardness (KHN), flexural strength (FS), and cytotoxicity analyses were carried out for each adhesive formulation. The adhesive resin of Adper Scotchbond Multi-Purpose (SBMP) was used as the commercially available reference for both the RP and cytotoxicity tests. Data were statistically analyzed using One-Way ANOVA and Tukey's test (p≤0.05).


RESULTS
All adhesives exhibited similar DC (p=0.1931). The RP of adhesives was improved with the addition of up to 5wt.% of HNTs (p<0.001). Adhesives containing 5-10wt.% of HNTs led to greater KHN when compared to the control (p<0.001). The FS was reduced only when 20wt.% of HNTs was added (p≤0.001). None of the prepared adhesives was cytotoxic.


CONCLUSIONS
The incorporation of up to 10wt.% of HNTs into the adhesive resins did not jeopardize the tested physical and biological properties.


CONCLUSIONS
When using HNTs as carriers of drugs/bioactive compounds, the amount of the former added into adhesive resin materials should not exceed 10wt.%; otherwise, a significant reduction in physicomechanical properties may be expected.
Department of Biomedical and Applied Sciences, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, IN 46202, USA.
Sabrina A
SA
Feitosa
Department of Biomedical and Applied Sciences, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, IN 46202, USA; Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas-UFPel, Pelotas, RS 96065-560, Brazil.
Eliseu A
EA
Münchow
Department of Biomedical and Applied Sciences, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, IN 46202, USA; Division of Operative Dentistry, Department of Conservative Dental Sciences, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
Afnan O
AO
Al-Zain
Department of Biomedical and Applied Sciences, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, IN 46202, USA.
Krzysztof
K
Kamocki
Department of Biomedical and Applied Sciences, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, IN 46202, USA.
Jeffrey A
JA
Platt
Department of Biomedical and Applied Sciences, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, IN 46202, USA. Electronic address: mbottino@iu.edu.
Marco C
MC
Bottino
D000538:Aluminum Silicates / Q000737:chemistry* / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D000077215:Clay; D003738:Dental Cements / Q000737:chemistry* / Q000633:toxicity; D004337:Drug Carriers; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D043942:Nanotubes; D012117:Resins, Synthetic / Q000737:chemistry* / Q000633:toxicity
D000538:Aluminum Silicates; D003738:Dental Cements; D004337:Drug Carriers; D012117:Resins, Synthetic; D000077215:Clay
Adhesive; Cytotoxicity; Drug delivery; Halloysite; Nanotubes; Radiopacity