Scanning electron micrograph analysis of hypomineralized enamel in permanent first molars.
First molars with cream- to yellow-coloured demarcated opacities of the enamel, often in combination with severe loss of substance, are common in many child populations. The aetiology is obscure.


OBJECTIVE
The aim of this study was to study the ultrastructure of the enamel of 10 affected teeth by means of scanning electron microscopy (SEM) in order to gain a better understanding of the clinical appearance and treatment problems of this condition, and to find some clues to its aetiology.


RESULTS
The basic enamel structure with enamel rods and interrod zones was found in porous parts of the enamel, as well as in normal parts, but the packing of the hydroxylapatite crystals seemed to be looser and less well organized in the porous parts. The border between normal and hypomineralized enamel was usually distinct, and followed the direction of the rods. The preserved basic structure indicates normal function of the ameloblasts during their secretion phase, but impaired function during their maturation stage.


CONCLUSIONS
Considering the poor etch profile, it seems reasonable to recommend removal of all affected enamel surrounding the cavity, if possible, and to use a glass ionomer filling with its chemical bonding to tooth substrate, when restoring first molars with remaining affected enamel.
Jälevik
B
B
Specialist Clinic of Pedodontics, Sahlgrenska University Hospital Mölndal, Mölndal, Sweden. birgitta.jalevik@vgregion.se
Dietz
W
W
Norén
J G
JG
D003743:Dental Enamel / Q000648:ultrastructure*; D003744:Dental Enamel Hypoplasia / Q000648:ultrastructure*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000473:pathology; D016062:Porosity