Objective: To detect ED1 gene mutation in three hypohidrotic ectodermal dysplasia (HED) nuclear families. Methods: Peripheral blood samples were obtained from three different families of hypohidrotic ectodermal dysplasia. Genomic DNA was extracted. Polymerase chain reaction, direct sequencing and restriction enzyme reaction were performed to identify the mutations. Results: Different missense mutation in ED1 gene were found in each family: C412G, A1201G and C1375T. Two of the mutations had not been previously reported. Conclusion: Mutations in the ED1 gene are responsible for the phenotypes of HED of the patients in the family.

Objective: To examine the ultrastructure of resin-infiltrated sclerotic dentine following the application of a three-step total-etching dentin adhesive. Methods: Naturally-occurring, non-carious cervical lesions on extracted premolars were bonded using a total-etching dentin adhesive-Scotchbond Multi-purpose. Artificially prepared wedge-shaped lesions were also made in sound premolars and restored using the same adhesive as control. The morphological change of the dentin surface conditioned with the etchant, and the hybrid zone and resin tags in the dentin-resin interface were studied by SEM . Results: Most dentinal tubules were obliterated by rod-like sclerotic casts in the non-carious cervical lesion, and could not be dissolved by Scotchbond Multi-purpose etchant.Both the hybrid zone and resin tags were observed in sclerotic dentin after restoration, although the resin tags were fewer and in lack of communications, the length of resin tags and the thickness of the hybrid zone were almost similar to those of the sound dentin. Conclusion: Bonding to sclerotic dentin is different from sound dentin, and may be compromised by the fewer resin tags and communications.