Comparison of gene expression profiles between dental pulp and periodontal ligament tissues in humans.

There are anatomical and functional differences between human dental pulp (DP) and periodontal ligament (PDL). However, the molecular biological differences and function of these tissues are poorly understood. In the present study, we employed a cDNA microarray array to screen for differentially expressed genes (DEGs) between human DP and PDL tissues, and used the online software WebGestalt to perform the functional analysis of the DEGs. In addition, the STRING database and KEGG pathway analysis were applied for interaction network and pathway analysis of the DEGs. DP and PDL samples were obtained from permanent premolars (n=16) extracted for orthodontic purposes. The results of the microarray assay were confirmed by RT-qPCR. The DEGs were found to be significantly associated with the extracellular matrix and focal adhesion. A total of 10 genes were selected to confirm the results. The mRNA levels of integrin alpha 4 (ITGA4), integrin alpha 8 (ITGA8), neurexin 1 (NRXN1) and contactin 1 (CNTN1) were significantly higher in the DP than in the PDL tissues. However, the levels of collagen type XI alpha 1 (COL11A1), aggrecan (ACAN), collagen type VI alpha 1 (COL6A1), chondroadherin (CHAD), laminin gamma 2 (LAMC2) and laminin alpha 3 (LAMA3) were higher in the PDL than in the DP samples. The gene expression profiles provide novel insight into the characterization of DP and PDL tissues, and contribute to our understanding of the potential molecular mechanisms of dental tissue mineralization and regeneration.

[Comparison between J-hook and micro-implant anchorage in the treatment of patients with bimaxillary protrusion].

OBJECTIVE: To compare the difference between J-hook and micro-implant anchorage in the treatment of patient with bimaxillary protrusion. METHODS: Thirty patients with bimaxillary protrusion were divided into two groups (J-hook and micro-implant groups) and treated with MBT appliance. Four first premolars were extracted in all patients. Cephalometric analyses were carried out before and after treatment. RESULTS: In J-hook group and micro-implant group,computerized cephalometric analysis revealed that before treatment U6C-PP was (12.4 +/- 0.2) mm and (12.5 +/- 0.1) mm, respectively,and after treatment U6C-PP was (12.6 +/- 0.1) mm and (12.8 +/- 0.1) mm,respectively. The difference between J-hook group and microimplant group was significant (P < 0.01). The other differences of cephalometric analyses between J-hook group and micro-implant group was not significant. CONCLUSIONS: Both J-hook and micro-implant could provide adequate anchorage in the treatment of patients with bimaxillary protrusion.