Molar Incisor Hypomineralization: Structure, Composition, and Properties

  • Erin K. MahoneyEmail author
  • Rami Farah


The first permanent molars in molar incisor hypomineralization (MIH) are characterized by localized demarcated lesions or opacities within the enamel. These lesions are often rough and plaque retentive and at risk of rapid caries and post-eruptive breakdown (PEB). There is increasing evidence to suggest that the physical, chemical and mechanical properties of MIH-affected enamel are different to those of otherwise healthy enamel. Studies suggest that the hardness and modulus of elasticity of MIH-affected enamel are reduced by between 50 and 75 % and are accompanied by a simultaneous 20 % reduction in mineral content. Furthermore, the protein content of affected enamel is up to 15 times higher than in sound enamel particularly in the darker brown opacities. These findings may explain why hypomineralized enamel fractures easily under occlusal function causing PEB. Scanning and transmission electron microscopic studies have shown that the microstructure of this enamel is more disorganized and, when etched with phosphoric acid, it does not show the typical etching pattern. This may contribute clinically to the compromised bonding of adhesive dental materials to affected teeth. Knowledge of the physical and mechanical properties and composition of developmentally defective enamel helps clinicians understand the challenges associated with treating affected individuals.


Hypomineralized enamel Mechanical properties Porosity Mineral content Microstructure Proteins 


  1. 1.
    He LH, Swain MV. Enamel – a “metallic-like” deformable biocomposite. J Dent. 2007;35(5):431–7.PubMedCrossRefGoogle Scholar
  2. 2.
    Crombie FA, Manton DJ, Palamara JE, Zalizniak I, Cochrane NJ, Reynolds EC. Characterisation of developmentally hypomineralised human enamel. J Dent. 2013;41(7):611–8.PubMedCrossRefGoogle Scholar
  3. 3.
    Mahoney E, Ismail FS, Kilpatrick N, Swain M. Mechanical properties across hypomineralized/hypoplastic enamel of first permanent molar teeth. Eur J Oral Sci. 2004;112(6):497–502.PubMedCrossRefGoogle Scholar
  4. 4.
    Kinney JH, Marshall SJ, Marshall GW. The mechanical properties of human dentin: a critical review and re-evaluation of the dental literature. Crit Rev Oral Biol Med. 2003;14(1):13–29.PubMedCrossRefGoogle Scholar
  5. 5.
    Cuy JL, Mann AB, Livi KJ, Teaford MF, Weihs TP. Nanoindentation mapping of the mechanical properties of human molar tooth enamel. Arch Oral Biol. 2002;47:281–91.PubMedCrossRefGoogle Scholar
  6. 6.
    Meredith N, Sherriff M, Setchell DJ, Swanson SAV. Measurement of the mircohardness and Young’s modulus of human enamel and dentine using an indentation technique. Arch Oral Biol. 1996;41:539–45.PubMedCrossRefGoogle Scholar
  7. 7.
    Xu HHK, Smith DT, Jahanmir S, Romberg E, Kelly JR, Thompson VP, et al. Indentation damage and mechanical properties of human enamel and dentin. J Dent Res. 1998;77(3):472–80.PubMedCrossRefGoogle Scholar
  8. 8.
    Crombie F, Cochrane NJ, Manton DJ, Palamara JE, Reynolds EC. Mineralisation of developmentally hypomineralised human enamel in vitro. Caries Res. 2013;47:259–63.PubMedCrossRefGoogle Scholar
  9. 9.
    Mahoney EK, Rohanizadeh R, Ismail FS, Kilpatrick NM, Swain MV. Mechanical properties and microstructure of hypomineralised enamel of permanent teeth. Biomaterials. 2004;25(20):5091–100.PubMedCrossRefGoogle Scholar
  10. 10.
    Jalevik B, Dietz W, Noren JG. Scanning electron micrograph analysis of hypomineralized enamel in permanent first molars. Int J Paediatr Dent. 2005;15(4):233–40.PubMedCrossRefGoogle Scholar
  11. 11.
    Suckling GW, Nelson DG, Patel MJ. Macroscopic and scanning electron microscopic appearance and hardness values of developmental defects in human permanent tooth enamel. Adv Dent Res. 1989;3(2):219–33.PubMedGoogle Scholar
  12. 12.
    Xie Z, Kilpatrick NM, Swain MV, Munroe PR, Hoffman M. Transmission electron microscope characterisation of molar-incisor-hypomineralisation. J Mater Sci Mater Med. 2008;19(10):3187–92.PubMedCrossRefGoogle Scholar
  13. 13.
    William V, Burrow MF, Palamara JEA, Messer LB. Microshear bond strength of resin composite to teeth affected by molar hypomineralization using 2 adhesive systems. Pediatr Dent. 2006;28(3):233–41.PubMedGoogle Scholar
  14. 14.
    Mahoney EK. Micromechanical and structural analysis of compromised dental tissues. PhD thesis, University of Sydney; 2005.Google Scholar
  15. 15.
    Farah RA, Swain MV, Drummond BK, Cook R, Atieh M. Mineral density of hypomineralised enamel. J Dent. 2010;38(1):50–8.PubMedCrossRefGoogle Scholar
  16. 16.
    Fearne J, Anderson P, Davis GR. 3D X-ray microscopic study of the extent of variations in enamel density in first permanent molars with idiopathic enamel hypomineralisation. Br Dent J. 2004;196(10):634–8. Discussion 25.PubMedCrossRefGoogle Scholar
  17. 17.
    Jalevik B, Noren JG. Enamel hypomineralization of permanent first molars: a morphological study and survey of possible aetiological factors. Int J Paediatr Dent. 2000;10(4):278–89.PubMedCrossRefGoogle Scholar
  18. 18.
    Rodd HD, Boissonade FM, Day PF. Pulpal status of hypomineralized permanent molars. Pediatr Dent. 2007;29(6):514–20.PubMedGoogle Scholar
  19. 19.
    Kilpatrick NM. New developments in understanding development defects of enamel: optimizing clinical outcomes. J Orthod. 2009;36:277–82.PubMedCrossRefGoogle Scholar
  20. 20.
    Jalevik B, Klingberg GA. Dental treatment, dental fear and behaviour management problems in children with severe enamel hypomineralization of their permanent first molars. Int J Paediatr Dent. 2002;12(1):24–32.PubMedGoogle Scholar
  21. 21.
    Farah RA, Drummond BK, Swain M, Williams S. Linking the clinical presentation of molar-incisor hypomineralisation to its mineral density. Int J Paediatr Dent. 2010;5:353–60.CrossRefGoogle Scholar
  22. 22.
    Da Costa-Silva CM, Ambrosano GMB, Jeremias F, De Souza JF, Mialhe FL. Increase in severity of molar–incisor hypomineralization and its relationship with the colour of enamel opacity: a prospective cohort study. Int J Paediatr Dent. 2011;21(5):333–41.PubMedCrossRefGoogle Scholar
  23. 23.
    Jalevik B, Odelius H, Dietz W, Noren J. Secondary ion mass spectrometry and X-ray microanalysis of hypomineralized enamel in human permanent first molars. Arch Oral Biol. 2001;46(3):239–47.PubMedCrossRefGoogle Scholar
  24. 24.
    Farah RA, Monk BC, Swain M, Drummond BK. Protein content of molar-incisor hypomineralisation enamel. J Dent. 2010;38(7):591–6.PubMedCrossRefGoogle Scholar
  25. 25.
    Parry David A, Brookes Steven J, Logan Clare V, Poulter James A, El-Sayed W, Al-Bahlani S, et al. Mutations in C4orf26, encoding a peptide with in vitro hydroxyapatite crystal nucleation and growth activity, cause amelogenesis imperfecta. Am J Hum Genet. 2012;91(3):565–71.PubMedCentralPubMedCrossRefGoogle Scholar
  26. 26.
    Wright JT, Hall KI, Yamauchi M. The enamel proteins in human amelogenesis imperfecta. Arch Oral Biol. 1997;42(2):149–59.PubMedCrossRefGoogle Scholar
  27. 27.
    Mangum JE, Crombie F, Kilpatrick NM, Manton DJ, Hubbard MJ. Surface integrity governs the proteome of hypomineralised enamel. J Dent Res. 2010;69:1160–5.CrossRefGoogle Scholar
  28. 28.
    Robinson C, Brookes SJ, Kirkham J, Shore RC, Bonass WA. Uptake and metabolism of albumin by rodent incisor enamel in vivo and postmortem: implications for control of mineralization by albumin. Calcif Tissue Int. 1994;55(6):467–72.PubMedCrossRefGoogle Scholar
  29. 29.
    Robinson C, Kirkham J, Brookes SJ, Shore RC. The role of albumin in developing rodent dental enamel: a possible explanation for white spot hypoplasia. J Dent Res. 1992;71(6):1270–4.PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Department of DentistryHutt Valley District Health BoardHataitai, WellingtonNew Zealand
  2. 2.Department of Oral SciencesUniversity of OtagoDunedinNew Zealand

Personalised recommendations