BACKGROUND: Dental porcelain crown containing Ni-Cr alloy has been widely used in modern dentistry. The dispute of its safety is limited in oral cavity and neighbor tissues, however, the relevance between Ni-Cr alloy and systemic disease, such as nephridium toxicosis, are poorly understood. OBJECTIVE: To analyze the possibility of Ni-Cr porcelain crown resulted nephropathy and to explore its long-term clinical safety.METHODS: Databases of VIP, CNKI, Wanfang, CBMdisc, Biosis Previews and BioOne were researched by computer with key words of "nickle chromium alloy, porcelain crown, nephridium toxicosis" both in Chinese and English. Literatures concerning Ni-Cr porcelain crown and toxicity of related metal ion were included, repetitive research was excluded. RESULTS AND CONCLUSION: By consulting literatures, the possibility of erosion and release of heavy metal ion lead to nephridium toxicosis were analyzed with following aspects: effects of Ni-Cr alloy corrosivity and its accumulation on oral cavity or systemic disease; direct toxicity of released metal ions from Ni-Cr alloy and susceptivity of nephridium toxicosis; and the possible ways for renal damage resulted by Ni-Cr ion. This study can provide a basis for the further research concerning security of dental porcelain crown containing Ni-Cr alloy.

Objective To investigate the characteristics of amygdala neural circuitry in comorbidity of late-life depression (LLD) and cognitive impairment. Methods Twenty-four LLD,eighteen amnestic mild cognitive impairments (aMCI),thirteen aMCI with depression (dMCI) and thirty cognitive normal (CN) subjects completed resting-state functional magnetic resonance imaging scan. Main effects of depression and MCI and their interactions on the intrinsic amygdala functional connectivity network ( AFCN) connectivity were examined. Behavioral significance of AFCN that voxel-wised amygdala connectivity correlating with de-pression severity and memory scores were also tested after controlling the effects of covariates,including age, gender,education, gray matter atrophy, and group. Results The immediate memory and delayed memory function in the aMCI group (-0. 75 ± 0. 77 and -1. 13 ± 0. 56) and the dMCI group (-1. 07 ± 0. 79 and-1. 00±0. 52) were significantly lower than those of the CN group (0. 46±0. 73 and 0. 60±0. 61),and the difference was statistically significant (P<0. 01). Depression and anxiety in the LLD group (1. 00±0. 53 and 0. 93±0. 98) and the dMCI group (0. 86±0. 80 and 0. 78±0. 82) were significantly higher than those of the CN group (-0. 92±0. 25 and -0. 74±0. 22),and the difference was statistically significant (P<0. 01). Brain network analysis showed that separated neural circuits were implicated in the depression and cognitive im-pairment. Importantly,interactive effects of depression and MCI on the AFCN were also identified,especially in the bilateral somatomotor area,inferior parietal cortex/precuneus,posterior cingulate cortex,right medial prefrontal cortex/dorsolateral prefrontal cortex and hippocampus. Behavioral significance of AFCN also re-vealed the distinctive neural circuits involved in the depression severity and memory deficits,respectively. Conjunction analysis further identified the overlapped neural circuits associated with depression and memory deficits were primarily in the left DLPFC,insula,hippocampus,right inferior prefrontal cortex and dorsomedi-al prefrontal cortex. Conclusions Depression and cognitive impairment synergistically facilitate functional decoupling of AFCN and thus compromise the integrity of amygdala networks. Distinct depression-related or MCI-related neural constructs represent the characteristics of clinical phenotype of depression or MCI alone, while overlapped circuits probably reveal the neural basis of comorbidity of LLD and MCI.