Synergistic effects of VE-TPGS and riboflavin in crosslinking of dentine

Daood U 1 , Matinlinna JP 2 , Fawzy AS 3

Affiliations 

  • 1 Clinical Dentistry, Restorative Division, Faculty of Dentistry, International Medical University Kuala Lumpur, 126, Jalan Jalil Perkasa 19, 57000 Bukit Jalil, Wilayah Persekutuan Kuala Lumpur, Malaysia
  • 2 Dental Materials Science, Applied Oral Sciences, Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Sai Ying Pun, Hong Kong SAR, China
  • 3 UWA Dental School, University of Western Australia, 17 Monash Avenue, Nedlands, WA 6009, Australia. Electronic address: amr.fawzy@uwa.edu.au
Dent Mater, 2019 02;35(2):356-367.
PMID: 30528297 DOI: 10.1016/j.dental.2018.11.031

Abstract

OBJECTIVE: Effect of d-alpha-tocopheryl poly(ethyleneglycol)-1000-succinate (VE-TPGS) with riboflavin-5'-phosphate solution on crosslinking of dentine collagen was investigated to analyze collagen's structural integrity.

METHODS: VE-TPGS was added to RF-solution, at RF/VE-TPGS (w/w) ratios of 0.125/0.250 and 0.125/0.500. Demineralized dentine beams were used (10wt.% phosphoric acid), rinsed using deionized-water and analysed using ELISA (Human MMP2 ELISA; Human CTSK/Cathepsin-K for MMP2 and Cathepsin K analysis). AFM of dentine collagen-fibrils structure was done before and after dentine specimens' placement in mineralization solution and tested after 14days in artificial saliva/collagenase (AS/Co) solution. The specimens were tested after 24h in mineralization solution for surface/bulk elastic modulus. Nano-indentation was carried out for each specimen on intertubular-dentine with lateral spacing of 400nm. Reduced elastic-modulus and nano-hardness were calculated and collagen content was determined using hydroxyproline-assay. Micro-Raman were performed. TEM was carried out to study structural variations of dentine-collagen in artificial-saliva (collagenase). Data were presented as mean±standard deviation and analyzed by SPSS v.15, by analysis of variance.

RESULTS: Synergetic effect of VE-TPGS was observed with RF through higher structural integrity of dentine collagen-fibrils shown by TEM/AFM. Superior surface/bulk mechanical stability was shown by nano-indentation/mechanical testing. Improvement in collagenase degradation resistance for hydroxyproline release was observed and lower endogenous-protease release of MMP-2/Cathepsin-K. Raman-analysis analysed chemical interactions between RF and collagen confirming structural-integrity of collagen fibrils after crosslinking. After 24h mineralization, AFM showed mineral depositions in close association with dentine-collagen fibrils with RF/VE-TPGS formulations.

SIGNIFICANCE: Potential synergetic effect of RF/VE-TPGS was observed by reflection of higher structural integrity and conformational-stability of dentine-collagen fibrils.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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