Association of P2RX7 functional variants with localized aggressive periodontitis.

OBJECTIVE: The purpose of this study was to investigate involvement of the P2X7 receptor in the rare condition, localized aggressive periodontitis. MATERIAL AND METHODS: Peripheral blood from 220 African Americans (103 with localized aggressive periodontitis and 117 healthy unrelated controls) was stimulated with lipopolysaccharide from E coli and Porphyromonas gingivalis. P2RX7 single nucleotide polymorphisms rs208294 (H155Y), rs1718119 (T348A), rs2230911 (T357S) and rs3751143 (E496A) were genotyped in 103 localized aggressive periodontitis patients and 117 healthy unrelated subjects. We examined genetic association between four P2RX7 single nucleotide polymorphisms and localized aggressive periodontitis, and tested for correlations between the single nucleotide polymorphisms and inflammatory response to lipopolysaccharide in blood samples from these patients. RESULTS: A significant association with localized aggressive periodontitis was observed with rs1718119 A (Thr) allele (P = 0.0063, odds ratio = 1.904) and with a haplotype containing this allele (P = 0.0075). Additionally, significant correlations with these data were found: the rs1718119 G allele correlated with greater production of IL-6, IL-2 and GM-CSF; the C (His) allele of rs208294 correlated with lower levels of IL-12p40; and the C (Thr) allele of rs2230911 correlated with greater levels of G-CSF. CONCLUSION: The data from these analyses support a possible biological relationship between P2RX7 genetic variants and inflammatory response in localized aggressive periodontitis patients.

Anti-Bacterial Properties and Biocompatibility of Novel SiC Coating for Dental Ceramic.

A 200 nm plasma-enhanced chemical vapor-deposited SiC was used as a coating on dental ceramics to improve anti-bacterial properties for the applications of dental prosthesis. A thin SiO2 (20 nm) in the same system was deposited first, prior to SiC deposition, to improve the adhesion between SiC to dental ceramic. Silane and methane were the precursors for SiC deposition, and the SiO2 deposition employed silane and nitrous oxide as the precursors. SiC antimicrobial activity was evaluated on the proliferation of biofilm, Streptococcus sanguinis, and Streptococcus mutans on SiC-coated and uncoated dental ceramics for 24 h. The ceramic coating with SiC exhibited a biofilm coverage of 16.9%, whereas uncoated samples demonstrated a significantly higher biofilm coverage of 91.8%, measured with fluorescence and scanning electron microscopic images. The cytotoxicity of the SiC coating was evaluated using human periodontal ligament fibroblasts (HPdLF) by CellTiter-BlueCell viability assay. After 24 h of HPdLF cultivation, no obvious cytotoxicity was observed on the SiC coating and control group; both sets of samples exhibited similar cell adhesion and proliferation. SiC coating on a ceramic demonstrated antimicrobial activity without inducing cytotoxic effects.