Basic Research| Volume 47, ISSUE 6, P939-946, June 2021

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A Novel Self-Mineralizing Antibacterial Tissue Repair Varnish to Condition Root-end Dentin in Endodontic Microsurgery

Published:February 25, 2021DOI:



      A novel 2-part varnish system containing chitosan nanoparticles (part 1) and chitosan-grafted hydroxyapatite precursor nanocomplex (part 2) was developed to condition the root-end dentin using the principle of biomineralization while rendering both antimicrobial efficacy and bioactivity. This in vitro study aimed to characterize and assess the effectiveness of the chitosan nanoparticles and chitosan-grafted hydroxyapatite precursor nanocomplex containing self-mineralizing antibacterial tissue repair varnish to condition as well as seal root-end dentin during endodontic microsurgery.


      In phase 1, the antibacterial properties and cellular response of the varnish were characterized. The antibacterial activity and cellular responses were evaluated using Enterococcus faecalis and periodontal ligament (PDL) fibroblasts, respectively. In phase 2, a resected root-end model was used to apply the 2-part varnish and examine the dentin-varnish interface using transmission electron microscopy. The percentage of root end sealed with time was determined using scanning electron microscopy (n = 6/time point). Statistical analysis was performed using 1-way analysis of variance where applicable.


      The part 1 and 2 of the varnish displayed significant antibacterial activity and reduced bacterial adherence/survival (P < .01). The attachment and spreading of PDL fibroblasts on the varnish-conditioned dentin was enhanced compared with unconditioned dentin (P < .01). In the resected root-end model, the 2-part varnish displayed a biomineralized varnish layer with close interaction with the subsurface dentin. Root-end coverage with the biomineralized layer increased with incubation time (P < .01), reaching approximately 95% coverage after 24 hours.


      The 2-part varnish system effectively conditioned/sealed the root end with a biomineralized layer while reducing bacterial load and promoting PDL fibroblast attachment. This therapeutic modification of root-end dentin could provide optimal conditions to enhance healing and improve prognosis in teeth with root-end cracks after endodontic microsurgery.

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        • von Arx T.
        • Jensen S.S.
        • Hänni S.
        • Friedman S.
        Five-year longitudinal assessment of the prognosis of apical microsurgery.
        J Endod. 2012; 38: 570-579
        • Nair P.N.
        On the causes of persistent apical periodontitis: a review.
        Int Endod J. 2006; 39: 249-281
        • Walton R.E.
        • Michelich R.J.
        • Smith G.N.
        The histopathogenesis of vertical root fractures.
        J Endod. 1984; 10: 48-56
        • Kishen A.
        Mechanisms and risk factors for fracture predilection in endodontically treated teeth.
        Endod Topics. 2006; 13: 57-83
        • Kim S.
        • Kratchman S.
        Modern endodontic surgery concepts and practice: a review.
        J Endod. 2006; 32: 601-623
        • Layton C.A.
        • Marshall J.G.
        • Morgan L.A.
        • Baumgartner J.C.
        Evaluation of cracks associated with ultrasonic root-end preparation.
        J Endod. 1996; 22: 157-160
        • Tawil P.Z.
        Periapical microsurgery: can ultrasonic root-end preparations clinically create or propagate dentinal defects?.
        J Endod. 2016; 42: 1472-1475
        • Saunders W.P.
        • Saunders E.M.
        • Gutmann J.L.
        Ultrasonic root-end preparation, part 2. Microleakage of EBA root-end fillings.
        Int Endod J. 1994; 27: 325-329
        • Abedi H.R.
        • Van Mierlo B.L.
        • Wilder-Smith P.
        • Torabinejad M.
        Effects of ultrasonic root-end cavity preparation on the root apex.
        Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1995; 80: 207-213
        • Min M.M.
        • Brown Jr., C.E.
        • Legan J.J.
        • Kafrawy A.H.
        In vitro evaluation of effects of ultrasonic root-end preparation on resected root surfaces.
        J Endod. 1997; 23: 624-628
        • von Arx T.
        • Steiner R.G.
        • Tay F.R.
        Apical surgery: endoscopic findings at the resection level of 168 consecutively treated roots.
        Int Endod J. 2011; 44: 290-302
        • Tawil P.Z.
        • Saraiya V.M.
        • Galicia J.C.
        • Duggan D.J.
        Periapical microsurgery: the effect of root dentinal defects on short- and long-term outcome.
        J Endod. 2015; 41: 22-27
        • Kishen A.
        • Shi Z.
        • Shrestha A.
        • Neoh K.G.
        An investigation on the antibacterial and antibiofilm efficacy of cationic nanoparticulates for root canal disinfection.
        J Endod. 2008; 34: 1515-1520
        • Tay F.R.
        • Pashley D.H.
        Guided tissue remineralisation of partially demineralised human dentine.
        Biomaterials. 2008; 29: 1127-1137
        • Chen Z.
        • Cao S.
        • Wang H.
        • et al.
        Biomimetic remineralization of demineralized dentine using scaffold of CMC/ACP nanocomplexes in an in vitro tooth model of deep caries.
        PLoS One. 2015; 10: e0116553
        • Cao Y.
        • Mei M.L.
        • Xu J.
        • et al.
        Biomimetic mineralisation of phosphorylated dentine by CPP-ACP.
        J Dent. 2013; 41: 818-825
        • Cao C.Y.
        • Mei M.L.
        • Li Q.L.
        • et al.
        Methods for biomimetic remineralization of human dentine: a systematic review.
        Int J Mol Sci. 2015; 16: 4615-4627
        • Shrestha A.
        • Kishen A.
        Antibacterial nanoparticles in endodontics: a review.
        J Endod. 2016; 42: 1417-1426
        • Shariatinia Z.
        Carboxymethyl chitosan: properties and biomedical applications.
        Int J Biol Macromol. 2018; 120: 1406-1419
        • Wang H.
        • Xiao Z.
        • Yang J.
        • et al.
        Oriented and ordered biomimetic remineralization of the surface of demineralized dental enamel using [email protected] nanoparticles guided by glycine.
        Sci Rep. 2017; 7: 40701
        • Wang Y.
        • Van Manh N.
        • Wang H.
        • et al.
        Synergistic intrafibrillar/extrafibrillar mineralization of collagen scaffolds based on a biomimetic strategy to promote the regeneration of bone defects.
        Int J Nanomedicine. 2016; 11: 2053-2067
        • Hashmi A.
        • Sodhi R.N.
        • Kishen A.
        Interfacial characterization of dentin conditioned with chitosan hydroxyapatite precursor nanocomplexes using time-of-flight secondary ion mass spectrometry.
        J Endod. 2019; 45: 1513-1521
        • Hashmi A.
        • Zhang X.
        • Kishen A.
        Impact of dentin substrate modification with chitosan-hydroxyapatite precursor nanocomplexes on sealer penetration and tensile strength.
        J Endod. 2019; 45: 935-942
        • Li F.C.
        • Kishen A.
        Microtissue engineering root canal dentine with crosslinked biopolymeric nanoparticles for mechanical stabilization.
        Int Endod J. 2018; 51: 1171-1180
        • Kokubo T.
        • Takadama H.
        How useful is SBF in predicting in vivo bone bioactivity?.
        Biomaterials. 2006; 27: 2907-2915
        • Shrestha A.
        • Shi Z.
        • Neoh K.G.
        • Kishen A.
        Nanoparticulates for antibiofilm treatment and effect of aging on its antibacterial activity.
        J Endod. 2010; 36: 1030-1035
        • Torabinejad M.
        • Pitt Ford T.R.
        Root end filling materials: a review.
        Endod Dent Traumatol. 1996; 12: 161-178
        • Craig K.R.
        • Harrison J.W.
        Wound healing following demineralization of resected root ends in periradicular surgery.
        J Endod. 1993; 19: 339-347
        • Hakki S.S.
        • Hakki E.E.
        • Nohutcu R.M.
        Regulation of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases by basic fibroblast growth factor and dexamethasone in periodontal ligament cells.
        J Periodontal Res. 2009; 44: 794-802
        • Thomas B.
        • Gupta K.
        In vitro biocompatibility of hydroxyapatite-added GIC: an SEM study using human periodontal ligament fibroblasts.
        J Esthet Restor Dent. 2017; 29: 435-441
        • Ramesh N.
        • Moratti S.C.
        • Dias G.J.
        Hydroxyapatite-polymer biocomposites for bone regeneration: a review of current trends.
        J Biomed Mater Res B Appl Biomater. 2018; 106: 2046-2057
        • Jeong J.
        • Kim J.H.
        • Shim J.H.
        • et al.
        Bioactive calcium phosphate materials and applications in bone regeneration.
        Biomater Res. 2019; 23: 4