Sealing effects of pinus massoniana bark extract on dentin tubule and its wear resistance in vitro / 西安交通大学学报(医学版)

Objective To observe the sealing effect of transient pinus massoniana bark extract (PMBE)pre-coating on dentin tubules and its wear resistance so as to provide an experimental basis for PMBE to be used to prevent and treat dentin hypersensitivity.Methods The model of dentin hypersensitivity was established by acid etching method.The samples were transient pre-coating with 80 g/L of PMBE ethanol solution,and then some of them experienced brushing wear treatment with ethanol group and fluorine vanish group as negative and positive controls.The surface and profile morphologies of the samples were observed using field emission scanning electron microscope (FESEM)in each group.The area of dentin tubular openings (ADTO)and percentage area of dentin tubular openings (PADTO)were also measured.Results The dentin tubules were opened completely and the lumen of dentin tubules was empty in ethanol group.The dentin tubules were completely or basically closed and some films or plugging could be seen in the lumen of dentin tubules in fluorine vanish/immediate group and PMBE/immediate group.The dentin tubules were partly opened and some wear marks could be seen on the dentin surface in fluorine vanish/wear groups,PMBE/wear groups.ADTO and PADTO in ethanol group were significantly higher than those in fluorine vanish groups and PMBE groups (P＜0.05).ADTO and PADTO did not significantly differ between fluorine vanish/wear groups and PMBE/wear groups (P＞0.05),which were all significantly higher than those in fluorine vanish/immediate group and PMBE/immediate group (P＜0.05).Conclusion Local transient pre-coating of PMBE ethanol solution can achieve fine immediate sealing effect of dentin tubules and some degree of wear resistance.

Characteristics of DUOXA2 gene mutation in children with congenital hypothyroidism / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the characteristics of DUOXA2 gene mutation and the genotype-phenotype relationship in children with congenital hypothyroidism (CH) in Guangzhou, China.</p><p><b>METHODS</b>A total of 20 CH patients with suspected thyroid dyshormonogenesis who had no DUOX2 gene mutation were enrolled. These patients who were born between 2011 and 2012 were screened and diagnosed with CH in the Guangzhou Newborn Screening Center. PCR and direct sequencing were used to analyze DUOXA2 gene mutation.</p><p><b>RESULTS</b>Among the 20 patients, 2 had p.Y246X/p.Y246X homozygous mutation; 4 had monoallelic heterozygous mutation, among whom 2 carried the known pathogenic mutation c.413-414insA, 1 carried p.Y246X, and 1 carried a novel mutation, p.G79R. Reevaluation was performed at the age of 2-3 years, and the results showed that the two patients with p.Y246X/p.Y246X homozygous mutation were manifested as transient and mild permanent CH, respectively. Among the four patients with monoallelic heterozygous mutation, the one who carried p.Y246X mutation was manifested as typical permanent CH, and the other three were manifested as transient CH.</p><p><b>CONCLUSIONS</b>DUOXA2 gene mutation is a common molecular pathogenic basis for CH children with suspected thyroid dyshormonogenesis in Guangzhou, and most of them are manifested as transient CH. There is no association between DUOXA2 genotypes and phenotypes. The novel mutation p.G79R is probably a pathogenic mutation.</p>

Anti-proteolytic capacity and bonding durability of proanthocyanidin-biomodified demineralized dentin matrix / 国际口腔科学杂志·英文版

Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin (PA) for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin-dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2% chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.