In Vitro Biocompatibility Evaluation of a Root Canal Filling Material That Expands on Water Sorption

Published:April 05, 2013DOI:



      CPoint is a polymeric endodontic point that takes advantage of water-induced, non-isotropic radial expansion to adapt to canal irregularities. This study evaluated the effects of CPoint on the viability and mineralization potential of odontoblast-like cells.


      The biocompatibility of CPoint and commercially available gutta-percha points was evaluated by using a rat odontoblast-like cell line (MDPC-23). Cell viability was evaluated with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, and confocal laser scanning microscopy. The mineralization potential of MDPC-23 cells, in the presence of the root-filling materials, was evaluated by examining the changes in osteogenic gene marker expression (quantitative real-time polymerase chain reaction), alkaline phosphatase activity, alizarin red S assay, and transmission electron microscopy.


      CPoint showed higher initial cytotoxicity compared with gutta-percha and Teflon (P < .05), which became nonsignificant after 4 immersion cycles. Significant differences were also found between eluents from CPoint and gutta-percha at 1:1 concentration (P < .05) but not at 1:10 or 1:100 concentration. Both materials induced minimal apoptosis-induced alteration in plasma membrane permeability, as evidenced by flow cytometry and confocal laser scanning microscopy. Compared with the Teflon negative control, CPoint and gutta-percha groups showed up-regulation of most osteogenic gene markers except for dentin sialophosphoprotein, which was down-regulated. Alkaline phosphatase activity and alizarin red assay for CPoint and gutta-percha were both significantly higher than for Teflon but not significantly different from each other (P > .05). Transmission electron microscopy showed discrete nodular electron-dense mineralization foci in all 3 groups.


      The in vitro biocompatibility of CPoint is comparable to gutta-percha with minimal adverse effects on osteogenesis after elution of potentially toxic components.

      Key Words

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Endodontics
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Schilder H.
        Cleaning and shaping the root canal.
        Dent Clin North Am. 1974; 18: 269-296
        • Haapasalo M.
        • Endal U.
        • Zandi H.
        • Coil J.M.
        Eradication of endodontic infection by instrumentation and irrigation solutions.
        Endod Topics. 2005; 10: 77-102
        • Schilder H.
        Filling root canals in three dimensions, 1967.
        J Endod. 2006; 32: 281-290
        • Glickman G.N.
        • Gutmann J.L.
        Contemporary perspectives on canal obturation.
        Dent Clin North Am. 1992; 36: 327-341
        • Whitworth J.
        Methods of filling root canals: principles and practices.
        Endod Topics. 2005; 12: 2-14
        • Kirkevang L.-L.
        • Hørsted-Bindslev P.
        Technical aspects of treatment in relation to treatment outcome.
        Endod Topics. 2002; 2: 89-102
        • de Chevigny C.
        • Dao T.T.
        • Basrani B.R.
        • et al.
        Treatment outcome in endodontics: the Toronto study—phase 4: initial treatment.
        J Endod. 2008; 34: 258-263
        • Cotton T.P.
        • Schindler W.G.
        • Schwartz S.A.
        • et al.
        A retrospective study comparing clinical outcomes after obturation with Resilon/Epiphany or gutta-percha/Kerr sealer.
        J Endod. 2008; 34: 789-797
        • Zmener O.
        • Pameijer C.H.
        Clinical and radiographic evaluation of a resin-based root canal sealer: an eight-year update.
        J Endod. 2010; 36: 1311-1314
        • Ng Y.L.
        • Mann V.
        • Gulabivala K.
        A prospective study of the factors affecting outcomes of nonsurgical root canal treatment: part 1—periapical health.
        Int Endod J. 2011; 44: 583-609
        • Ng Y.L.
        • Mann V.
        • Gulabivala K.
        A prospective study of the factors affecting outcomes of non-surgical root canal treatment: part 2—tooth survival.
        Int Endod J. 2011; 44: 610-625
        • Hale R.
        • Gatti R.
        • Glickman G.N.
        • Opperman L.A.
        Comparative analysis of carrier-based obturation and lateral compaction: a retrospective clinical outcomes study.
        Int J Dent. 2012; 2012 (Epub 2012 Apr 11.): 954675
      1. Highgate DJ, Frankland JD. Deformable polymeric compositions. United States Patent number 4,565,722. January 21, 1986.

      2. Highgate DJ, Lloyd JA. Expandable/contractable composition for surgical or dental use. United States Patent number 7,210,935. May 1, 2007.

        • Geurtsen W.
        Biocompatibility of root canal filling materials.
        Aust Endod J. 2001; 27: 12-21
        • Dahl J.E.
        Toxicity of endodontic filling materials.
        Endod Topics. 2005; 12: 39-43
        • Bryan T.E.
        • Khechen K.
        • Brackett M.G.
        • et al.
        In vitro osteogenic potential of an experimental calcium silicate-based root canal sealer.
        J Endod. 2010; 36: 1163-1169
        • Wei W.
        • Qi Y.P.
        • Nikonov S.Y.
        • et al.
        Effects of an experimental calcium aluminosilicate cement on the viability of murine odontoblast-like cells.
        J Endod. 2012; 38: 936-942
        • Moghaddame-Jafari S.
        • Mantellini M.G.
        • Botero T.M.
        • et al.
        Effect of ProRoot MTA on pulp cell apoptosis and proliferation in vitro.
        J Endod. 2005; 31: 387-391
        • de Mendonça A.A.
        • Souza P.P.
        • Hebling J.
        • Costa C.A.
        Cytotoxic effects of hard-setting cements applied on the odontoblast cell line MDPC-23.
        Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007; 104: e102-e108
        • Lessa F.C.
        • Aranha A.M.
        • Hebling J.
        • Costa C.A.
        Cytotoxic effects of White-MTA and MTA-Bio cements on odontoblast-like cells (MDPC-23).
        Braz Dent J. 2010; 21: 24-31
      3. Botero T, Otero-Corchon V, Nör J. MDPC-23: a rat odontoblast-like cell line. IADR General Session, June 20–23, 2012. Iguaçu Falls, Brazil. Abstract 328.

        • Vermes I.
        • Haanen C.
        • Steffens-Nakken H.
        • Reutelingsperger C.
        A novel assay for apoptosis: flow cytometric detection of phosphatidylserine expression on early apoptotic cells using fluorescein labelled Annexin V.
        J Immunol Methods. 1995; 184: 39-51
        • Gronthos S.
        • Mankani M.
        • Brahim J.
        • et al.
        Postnatal human dental pulp stem cells (DPSCs) in vitro and in vivo.
        Proc Natl Acad Sci U S A. 2000; 97: 13625-13630
        • Hao J.
        • Zou B.
        • Narayanan K.
        • George A.
        Differential expression patterns of the dentin matrix proteins during mineralized tissue formation.
        Bone. 2004; 34: 921-932
        • Almushayt A.
        • Narayanan K.
        • Zaki A.E.
        • George A.
        Dentin matrix protein 1 induces cytodifferentiation of dental pulp stem cells into odontoblasts.
        Gene Ther. 2006; 13: 611-620
        • Miyazaki T.
        • Kanatani N.
        • Rokutanda S.
        • et al.
        Inhibition of the terminal differentiation of odontoblasts and their transdifferentiation into osteoblasts in Runx2 transgenic mice.
        Arch Histol Cytol. 2008; 71: 131-146
        • Li S.
        • Kong H.
        • Yao N.
        • et al.
        The role of runt-related transcription factor 2 (Runx2) in the late stage of odontoblast differentiation and dentin formation.
        Biochem Biophys Res Commun. 2011; 410: 698-704
        • Livak K.J.
        • Schmittgen T.D.
        Analysis of relative gene expression data using real-time quantitative PCR and the 2-ΔΔCT method.
        Methods. 2001; 25: 402-408
        • Bessay O.A.
        • Lowry O.H.
        • Brock M.J.
        A method for the rapid determination of alkaline phosphatase with five cubic millimeters of serum.
        J Biol Chem. 1946; 164: 321-329
        • Niu L.N.
        • Jiao K.
        • Qi Y.P.
        • et al.
        Intrafibrillar silicification of collagen scaffolds for sustained release of stem cell homing chemokine in hard tissue regeneration.
        FASEB J. 2012; 26: 4517-4529
        • Gregory C.A.
        • Gunn W.G.
        • Peister A.
        • Prockop D.J.
        An alizarin red-based assay of mineralization by adherent cells in culture: comparison with cetylpyridinium chloride extraction.
        Anal Biochem. 2004; 329: 77-84
        • Wang X.
        • Xia Y.
        • Liu L.
        • et al.
        Comparison of MTT assay, flow cytometry, and RT-PCR in the evaluation of cytotoxicity of five prosthodontic materials.
        J Biomed Mater Res B Appl Biomater. 2010; 95: 357-364
        • Pascon E.A.
        • Spångberg L.S.
        In vitro cytotoxicity of root canal filling materials: 1—gutta-percha.
        J Endod. 1990; 16: 429-433
        • Goldstein P.
        • Kroemer G.
        Cell death by necrosis: toward a molecular definition.
        Trends Biochem Sci. 2007; 32: 37-43