[Three-dimensional finite element analysis of cement flow in abutment margin-crown platform switching].

OBJECTIVE: To analyze the cement flow in the abutment margin-crown platform switching structure by using the three-dimensional finite element analysis, in order to prove that whether the abutment margin-crown platform switching structure can reduce the inflow depth of cement in the implantation adhesive retention. METHODS: By using ANSYS 19.0 software, two models were created, including the one with regular margin and crown (Model one, the traditional group), and the other one with abutment margin-crown platform switching structure (Model two, the platform switching group). Both abutments of the two models were wrapped by gingiva, and the depth of the abutment margins was 1.5 mm submucosal. Two-way fluid structure coupling calculations were produced in two models by using ANSYS 19.0 software. In the two models, the same amount of cement were put between the inner side of the crowns and the abutments. The process of cementing the crown to the abutment was simulated when the crown was 0.6 mm above the abutment. The crown was falling at a constant speed in the whole process spending 0.1 s. Then we observed the cement flow outside the crowns at the time of 0.025 s, 0.05 s, 0.075 s, 0.1 s, and measured the depth of cement over the margins at the time of 0.1 s. RESULTS: At the time of 0 s, 0.025 s, 0.05 s, the cements in the two models were all above the abutment margins. At the time of 0.075 s, in Model one, the gingiva was squeezed by the cement and became deformed, and then a gap was formed between the gingiva and the abutment into which the cement started to flow. In Model two, because of the narrow neck of the crown, the cement flowed out from the gingival as it was pressed by the upward counterforce from the gingival and the abutment margin. At the time of 0.1 s, in Model one, the cement continued to flow deep inside with the gravity force and pressure, and the depth of the cement over the margin was 1 mm. In Model two, the cement continued to flow out from the gingival at the time of 0.075 s, and the depth of the cement over the margin was 0 mm. CONCLUSION: When the abutment was wrapped by the gingiva, the inflow depth of cement in the implantation adhesive retention can be reduced in the abutment margin-crown platform switching structure.

Whole-genome array CGH evaluation for replacing prenatal karyotyping in Hong Kong.

OBJECTIVE: To evaluate the effectiveness of whole-genome array comparative genomic hybridization (aCGH) in prenatal diagnosis in Hong Kong. METHODS: Array CGH was performed on 220 samples recruited prospectively as the first-tier test study. In addition 150 prenatal samples with abnormal fetal ultrasound findings found to have normal karyotypes were analyzed as a 'further-test' study using NimbleGen CGX-135K oligonucleotide arrays. RESULTS: Array CGH findings were concordant with conventional cytogenetic results with the exception of one case of triploidy. It was found in the first-tier test study that aCGH detected 20% (44/220) clinically significant copy number variants (CNV), of which 21 were common aneuploidies and 23 had other chromosomal imbalances. There were 3.2% (7/220) samples with CNVs detected by aCGH but not by conventional cytogenetics. In the 'further-test' study, the additional diagnostic yield of detecting chromosome imbalance was 6% (9/150). The overall detection for CNVs of unclear clinical significance was 2.7% (10/370) with 0.9% found to be de novo. Eleven loci of common CNVs were found in the local population. CONCLUSION: Whole-genome aCGH offered a higher resolution diagnostic capacity than conventional karyotyping for prenatal diagnosis either as a first-tier test or as a 'further-test' for pregnancies with fetal ultrasound anomalies. We propose replacing conventional cytogenetics with aCGH for all pregnancies undergoing invasive diagnostic procedures after excluding common aneuploidies and triploidies by quantitative fluorescent PCR. Conventional cytogenetics can be reserved for visualization of clinically significant CNVs.

A prenatal case of split-hand malformation associated with 17p13.3 triplication - a dilemma in genetic counseling.

Copy number gain of 17p13.3 has been shown to be associated with developmental delay/autism and Split-Hand-Foot malformation. We report a case of fetus with bilateral split-hand malformation detected on prenatal ultrasound. Array comparative genomic hybridization detected 2 maternally inherited copy number gains in the 17p13.3 region with one of them involving the BHLHA9 gene and part of the YWHAE gene. The mother is normal in intelligence with mild right foot anomaly only. Although the BHLHA9 copy gain is known to be associated with split-hand-foot malformation, the penetrance and expressivity is highly variable. More challenging is the effect of partial YWHAE copy number gain on neurodevelopment is inconclusive based on current literature. This case highlights the difficulties of prenatal genetic counseling in array comparative genomic hybridization findings in clinical situation with incomplete understanding of genotype-phenotype correlation.

A newborn with a 790 kb chromosome 17p13.3 microduplication presenting with aortic stenosis, microcephaly and dysmorphic facial features - is cardiac assessment necessary for all patients with 17p13.3 microduplication?

While deletion of chromosome 17p13.3 (encompassing PAFAH1B1 and YWHAE genes) is known to result in Miller-Dieker syndrome (OMIM 247200), 17p13.3 microduplication gives rise to a condition commonly associated with developmental delay and autism spectrum disorder. We report a Chinese newborn presenting with dysmorphic features, microcephaly and valvar aortic stenosis, who was confirmed to have a 790 kb microduplication in chromosome 17p13.3 by array comparative genomic hybridization (aCGH). The patient passed away at 4 months of age with presumably life-threatening event associated with his cardiac condition. From literature review, congenital heart diseases of various kinds were identified in up to 20% of patients with 17p13.3 microduplication. We propose cardiac assessment should be part of the comprehensive evaluation of these patients.

Intensive insulin therapy in severe acute pancreatitis: a meta-analysis and systematic review.

OBJECTIVE: To assess the effect of intensive insulin therapy on outcomes of patients with severe acute pancreatitis. METHODS: Relevant literatures cited in these electronic databases: Medline, Chinese Biomedical Literature Database, China National Knowledge Infrastructure (CNK1) database, and Excerpta Medical database (Embase) were systematically searched for randomized controlled trials (RCTs) in which intensive insulin therapy was used in severe acute pancreatitis. Length of hospitalization, acute physiology and chronic health evaluation II (APACHE II) score, incidence of complications, and adverse effects were recorded for statistical analysis. The methodological quality of the eligible studies was assessed by Jadad scale. The results were analysed by Revman 4.3 software. RESULTS: Three studies, which included a total of 118 cases, were finally reviewed. The methodological quality of the trials varied substantially In patients with severe acute pancreatitis, intensive insulin therapy was associated with shorter length of hospitalization (weighted mean difference (WMD) = -12.13, 95% confidence interval (CI) [-15.48, 8.78], p > 0.00001) and lower APACHE II score after 72 hours treatment (WMD = -3.80, 95% CI [-4.88,2. 72], p > 0.00001). One study reported insulin-related adverse event. CONCLUSION: In patients with severe acute pancreatitis, intensive insulin therapy could relieve the patient's condition earlier and shorten the length of hospitalization without serious adverse effect.