Objective：To analyze two mutations in voltage gated chloride channel 7 gene (CLCN7) of two osteopetrosis patients using bioinformatic methods, and compare the effects of mutations on protein structure and physicochemical characteristics, so as to predict the damaging effect of the mutations on the disease development. Methods：Genomic DNA were collected from peripheral blood of two osteopetrosis patients and their family members. CLCN7 gene was PCR amplified and sequenced. NCBI website, PolyPhen-2, DNAStar, SWISS MODEL were used to analyze the effect of the mutated genes. Results：Case 1 was diagnosed as intermediate autosomal recessive osteopetrosis (IARO), and his CLCN7 gene showed a de novo homozygous mutation c.1409 C>T in exon 16, which resulted in a residue substitution from proline to leucine (c.1409 C＞T; p.Pro470Leu). Case 2 was diagnosed as autosomal dominant osteopetrosis type Ⅱ (ADOⅡ). The sequence analysis revealed a heterozygous mutation c.856 C>T in exon 10 of CLCN7 gene, which resulted in arginine to tryptophan residue substitution (c.856 C＞T; p.Arg286Trp). Both of the mutations are located in highly conserved domain among different species. The mutations cause the changes in the secondary structure, tertiary structure and physicochemical properties and so on. Conclusions：Multiple bioinformatic analyses indicate that the mutations in CLCN7 gene (c.1409 C＞T and c.856 C＞T) can change the molecule structure and affect biological function of ClC-7, which shows a damaging effect and might be the key of disease development in the patients.

Objective：To screen EDA gene in a family with X-linked hypohidrotic ectodermal dysplasia and lay a basis for genetic counseling and prenatal diagnosis. Methods：Genomic DNA was isolated from the blood samples of all available family members. All exons of EDA were amplified using polymerase chain reaction (PCR) and then directly sequenced. Results：A missense mutation (c. 1045 G>A) was identified in exon 9 of EDA which changed Ala into Thr in the coding amino acids（p. 349 A>T）. Conclusions：This mutation caused X-linked hypohidrotic ectodermal dysplasia in the investigated family.

Objective：To collect families with hereditary dentin disorders in Chinese population and perform analysis on phenotype and disease classification, as well as to screen the mutations on the candidate gene DSPP，and to explore the correlation between gene mutation and phenotype. Methods：Comprehensive oral examination was performed for available affected individuals in collected families with dentinogenesis imperfacta (DGI). Clinical phenotypes and classification diagnosis were analyzed in each family. Genomic DNA was extracted from peripheral blood in all investigated members. Mutations screening was performed by amplifying all coding regions and splicing junctions of DSPP and sequencing the products. The results were analyzed by BLAST searching, combined with GENBANK polymorphisms and mutations database of DSPP. Results：A total of 3 families with DGI were enrolled in the study. One of them presents unique xerostomia phenotype besides the typical clinical features of DGI type Ⅱ (DGI-Ⅱ). Among 3 families, no mutation was found in the DSP region, and a common frameshift mutation c.3546-3550delTAGCAinsG of DSPP was revealed in DPP coding region in two families, which was identical to a previous reported mutation in other family with DGI-Ⅱ. Conclusions：The present study reported a novel phenotype in DGI-Ⅱ, and further suggested that DPP mutations be an important pathogenic factor for DGI-Ⅱ, and that c.3546-3550delTAGCAinsG might be a hot point mutation of DSPP in Chinese population.

Objective To explore the effect of transcription factor GATA4 on bone formation and mineralization. Methods Wnt1-Cre mice were mated to GATA4fl/fl mice by cre-loxp gene conditional knockout technique, and conditional knockout GATA4 gene of neural crest cell mice (Wnt1-Cre;GATA4fl/fl) were produced. 2-week-old GATA4 conditional knockout (CKO) mice and wild type (WT) mice were sacrificed and then Micro-CT was conducted to compare the size and volume of craniofacial bones such as calvarial bone, palate bone and right mandible bone. Results Compared with WT mice, the skull bone, palate bone and mandible bone of CKO mice were smaller, and the width of midpalatal suture was increased. The mandible of CKO mice also showed decreased BV/TV and Tb.N (P<0.05) values, and increased Tb.Sp value; Tb.N was not significantly different (P>0. 05). Conclusions These results indicate an important role of GATA4 in craniofacial bone development and mineralization.

Objective：The aim of the study was to fabricate the novel silk fibroin/strontium carbonate nanofibrous membranes (SrCO3-SFM) and explore the effects on the bioactivity of BMSCs. Methods：We fabricated the SrCO3-SFM by electrospinning and biomineralization process. SEM and XRD were used to determine the structure characteristics of SrCO3-SFM. To examine the biocompatibility of SrCO3-SFM, we investigated cell proliferation and differentiation by cck-8, ALP and RT-PCR. Results：The results showed lots of SrCO3 particles, which evenly distributed on the nanofibers. In vitro tests, the SrCO3-SFM promoted the activity of ALP and extracellular matrix mineralization and increased the of osteogenic differentiation related genes, such as RUNX2, BSP and OCN. Conclusions：The SrCO3-SFM material has good cell compatibility, promoting mesenchymal stem cell proliferation and osteogenic differentiation.

Objective：To observe the effect of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) on the of EphA4 in mouse marrow stromal cell line ST-2. Methods：ST-2 cells were co-cultured with 10 μg/mL of Pg-LPS at 1 d, 3 d and 7 d. EphA4 gene and the osteogenic related genes (Runx2, ColⅠ and ALP) were detected by RT-PCR. Results：Compared with Pg-LPS group, at the 1 d, 3 d and 7 d, the EphA4 mRNA was significantly decreased by 2.5 folds，2.4 folds and 2.3 folds in control group. At the same time，the osteogenic related gene Runx2 in the experimental group were significantly decreased (P < 0.01) as compared with that of the control group at 1 d and 3 d, but on the 7 d this was not obvious; as to the osteogenic related genes ColⅠand ALP s in 1 d, 3 d and 7 d, the experimental group was less than the control group, and the difference was statistically significant (P<0.01). Conclusions：Pg-LPS can inhibit the s of EphA4 gene and osteogenic related genes Runx2, ColⅠand ALP in ST-2 cells in the osteogenetic differentiation.

Objective：To determine whether there is significant difference in of rpl gene of fluoride-resistant Streptococcus mutans cultivated in fluorine-containing medium. Methods：Fluoride-resistant Streptococcus mutans were subcultured in BHI containing 1g/L NaF or without NaF, and its parental strain was subcultured in BHI without NaF. After 11h (logarithmic phase) or 20h (platform stage) cultivation, total RNA of the three groups were extracted and reverse transcribed，and the impression level of rpl were detected by qRT-PCR. Results：The of rpl gene of fluoride-resistant Streptococcus mutans cultivated in fluorine-containing medium, compared with fluoride-free medium, had no significant difference in the logarithmic phase (P＞0.05), but increased in the platform stage (P<0.001). Compared with its parental strain, the of rpl gene of fluoride-resistant Streptococcus mutans, whether cultivated in fluorine-containing or fluorine-free medium, was significantly decreased (P<0.001). Conclusions：The presence of fluoride could weaken the decrease of the of rpl gene in fluoride-resistant Streptococcus mutans, compared with its parental strain, in the platform stage, but had no influence in the logarithmic phase.

Orofacial clefts (OFCs) are the commonest craniofacial birth defects in human which are caused by the interaction between environmental and genetic factors. Most OFCs are non-syndromic (NS) cases in which clefting occurs as the only malformation in the affected infant. Although previous studies of linkage and candidate genes, and more recently, several genome-wide association studies (GWAS), have reported multiple candidate genes and chromosomal regions associated with NSOFC, the underlying genetic architecture of this birth defect remains largely unknown. This paper reviewed the progress in molecular genetics of orofacial clefting.

Tooth wear is one of the most common physiological phenomenon, excessive wear can damage tooth,dental pulp,periodontal tissues and temporomandibular joint, affecting masticatory function and beauty. At present, the treatment methods of wear are limited and focus on prevention. Generalized wear can be divided into abrasion, attrition and erosion, tooth wear is the result of them. It is widely known that tooth wear is related to many factors, macroeconomic factors such as environmental factors, physiological factors, the development of oral behavioral factors and iatrogenic factors, micro factors such as micro cracks on tooth surface and enamel rod arrangement. This paper reviews the classification and related factors of tooth attrition. This article reviews the classification and related factors of tooth attrition.