Thickness and microhardness of deciduous tooth enamel with known DLX3 mutation.
OBJECTIVE
To investigate the thickness and hardness of teeth affected by a 2-bp deletion (c.561_562delCT) in the DLX3 gene.


METHODS
Extracted maxillary deciduous second molar was collected from the affected individual at age 12 years 7 months. Samples were sectioned buccolingually after embedding in epoxy resin. We measured the enamel thickness and microhardness and performed an elemental analysis using an electron probe microanalyser.


RESULTS
On average, the hardness of the enamel with a 2-bp deletion in DLX3 was about 53% of normal enamel hardness. The mutant enamel thickness was about half of the thickness of the normal control. The calcium level in the enamel with the 2-bp deletion was slightly decreased, while the magnesium level was slightly increased, in comparison to levels measured for normal teeth.


CONCLUSIONS
This study shows that enamel affected by a 2-bp deletion in DLX3 has reduced thickness as well as diminished microhardness. These data may explain the severe attrition and interdental spacing observed in affected individuals.
Hyun
Hong-Keun
HK
Department of Pediatric Dentistry, Dental Research Institute and BK21 Program, School of Dentistry, Seoul National University, Seoul, South Korea.
Kim
Jung-Wook
JW
D001031:Apatites / Q000032:analysis; D020029:Base Pairing / Q000235:genetics; D002118:Calcium / Q000032:analysis; D016022:Case-Control Studies; D002648:Child; D003596:Cytosine; D003743:Dental Enamel / Q000737:chemistry / Q000648:ultrastructure*; D003804:Dentin / Q000737:chemistry / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D017353:Gene Deletion; D006244:Hardness; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008274:Magnesium / Q000032:analysis; D008297:Male; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000737:chemistry / Q000648:ultrastructure; D009811:Odontometry; D010710:Phosphates / Q000032:analysis; D013941:Thymine; D014094:Tooth, Deciduous / Q000737:chemistry / Q000648:ultrastructure*; D014157:Transcription Factors / Q000235:genetics*
D001031:Apatites; C088334:Distal-less homeobox proteins; D018398:Homeodomain Proteins; D010710:Phosphates; D014157:Transcription Factors; D003596:Cytosine; D008274:Magnesium; D013941:Thymine; D002118:Calcium