Objective:To measure the effect of disinfection on dimension stability of four high polymer impression materials which were separately immersed in 20 ml/L glutaraldehyde solution.Methods:Fifteen plaster replication models of four high polymer impression materials(Impregum Penta polyether, Express-Putty silicone, Silagum-Putty silicone, GC EXAFINE silicone) were made on the same metal master cast respectively. Vertical and horizontal dimensions between landmarks on the masters and plaster casts were measured with an optical microscope,one-way ANOVA was used to compare the measurements among the materials.Results:The difference between the masters and Casts in horizontal distances measured on Express-Putty silicone impression material produced models was longer than those on other high polymer impression materials produced ones after disinfection for 20 minutes and beyond clinical requirement. Compared with metal master cast, the difference became significant when these four silicone impression materials were disinfected for 40 minutes. Conclusion: Among the four kinds of impression materials, the Express-Putty silicone material is relatively the most accurate one after disinfection for 20 minutes.

Objetive:To detect the gene mutation of a patient with anhidrotic ectodermal dysplasia. Methods: Genomic DNA was extracted from the peripheral blood of the patient and all the exon fragments were obtained by PCR. These fragments were sequenced directly. Results: In EDA gene a novel base transition was detected: -48A→G. Conclusion: There is a new base transition in EDA gene in this patient