Oral Diseases. 2018;24:384–392.
Received: 9 June 2017
Revised: 20 July 2017
Accepted: 21 July 2017
Mineral features of connective dental hard tissues in
hypoplastic amelogenesis imperfecta
| C Behets
| L Mansour
| S Ghoul-Mazgar
© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved
Laboratory of Histology and Embryology,
Laboratory of Dento-Facial, Clinical and
Biological Approach (ABCDF), Faculty of
Dental Medicine, University of Monastir,
Pôle de Morphologie, Institut de Recherche
Expérimentale et Clinique, Université
Catholique de Louvain, Brussels, Belgium
Sonia Ghoul-Mazgar, Laboratory of Histology
and Embryology, Laboratory of Dento-Facial,
Clinical and Biological Approach (ABCDF),
Faculty of Dental Medicine, University of
Objective: To explore the mineral features of dentin and cementum in hypoplastic
Amelogenesis imperfecta AI teeth.
Materials and methods: Forty- four (44) teeth cleaned and free of caries were used: 20
control and 24 affected by hypoplastic amelogenesis imperfecta. Thirty- two teeth
were studied by pQCT, cut in sections, and analyzed under microradiography, polar-
ized light microscopy, and confocal Raman spectroscopy. Eight teeth were observed
under scanning electron microscope. Four teeth were used for an X- ray diffraction.
The mineral density data were analyzed statistically with the Mann–Whitney U test,
using GraphPad InStat software.
Results: Both coronal dentin and radicular dentin were less mineralized in AI teeth
when compared to control (respectively 6.2% and 6.8%; p < .001). Root dentinal walls
were thin and irregular, while the cellular cementum layers were thick, reaching some-
times the cervical region of the tooth. Regular dentinal tubules and sclerotic dentin
areas were noticed. Partially tubular or cellular dysplastic dentin and hyper- , normo- ,
or hypomineralized areas were noticed in the inter- radicular areas of hypoplastic AI
teeth. The main mineral component was carbonate hydroxyapatite as explored by
Raman spectroscopy and X- ray diffraction.
Conclusions: Dentin and cementum in hypoplastic AI teeth are (i) hypomineralized, (ii)
constituted of carbonate hydroxyapatite, and (iii) of non- homogenous structure.
amelogenesis imperfecta, dental cementum, dentin, hydroxyapatites
1 | INTRODUCTION
Amelogenesis imperfecta (AI) is a heterogeneous group of hereditary
disorders that may affect the enamel of teeth (Gadhia, McDonald,
Arkutu, & Malik, 2012). This disorder is classified into four main
groups, depending on the clinical presentation of the defects and
the stage of enamel formation that is primarily affected (Aldred,
Savarirayan, & Crawford, 2003). These groups are identified as (i) hy-
poplastic, (ii) hypocalcified/hypomineralized, (iii) hypomature, and (iv)
hypomineralized/hypomature AI with taurodontism. For the hypoplas-
tic type, pathological processes of mineralization, called calcinosis, are
particularly described in the connective tissues of AI patients. Such
calcinosis could be described in either kidneys, gingivae, or dental pulp
(de la Dure- Molla et al., 2014). The complex process by which precip-
itations of inorganic compounds within these organic matrices occur
remains unclear. Besides, little is known about the structure and the
mineralized compound of the dental hard tissues of mesenchymal ori-
gin such as dentin and cementum in the context of AI and particularly
for the hypoplastic type.
Dentin forms the largest portion of a tooth. It contains 70% car-
bonated apatite, 20% organic matrix mainly constituted by type I
Approval number 2015-Histo-001 was given by the institutional reviewing Board of the
Faculty of Dental Medicine of Monastir (Tunisia) for the study in September 2015.