Influence of type of restorative materials and surface wetness conditions on intraoral scanning accuracy

OBJECTIVES

To assess the influence of different restorative materials and surface wetness on intraoral scanning accuracy.

METHODS

Reference casts with an extracted second premolar and first and second molar were digitized (L2). Four groups were established according to the material of the first molar: natural tooth (control), zirconia (Z), lithium disilicate (LD), and nanoceramic resin crown (NC). Four subgroups were developed: dry, low-, mild-, and high-wetness subgroups (n=15). All the scans were completed by using an intraoral scanner (TRIOS 3). In the control-dry subgroup, the reference cast was dry. In the control-low subgroup, artificial saliva was sprayed with a 1 mL/min volumetric flow for 4 seconds. In the control-mild and control-high subgroups, the same procedures as in the control-low subgroup were performed, but with a volumetric flow of 4 and of 8 mL/min, respectively. In the Z, LD and NC groups, each crown was fabricated with its respective material. Trueness was analyzed using 2-way ANOVA and Bonferroni tests. The Levene and Bonferroni tests were used to assess precision (α=.05).

RESULTS

Material (P<.001) and wetness (P<.001) significantly influenced trueness and precision. The mild and high subgroups revealed lower trueness and precision compared with the dry and low subgroups. The control, Z, and LD groups under dry and low wetness conditions showed better trueness compared with the NC group, but the materials tested had no significant precision discrepancies. Under mild wetness conditions, all the materials showed no significant trueness discrepancies. Under high wetness conditions, the LD group demonstrated the best trueness and precision.

CONCLUSIONS

The restorative materials and surface wetness tested influenced scanning trueness and precision of the IOS assessed.

CLINICAL SIGNIFICANCE

Dried surfaces are recommended to maximize the scanning accuracy values of the IOS tested. Overall, the presence of saliva can reduce the performance of the IOS tested.

Arylsulfonyl histamine derivatives as powerful and selective α-glucosidase inhibitors

A series of simple N-arylbenzenesulfonyl histamine derivatives were prepared and screened against α-glucosidase. Inhibition was in the micromolar range for several N α,N τ-di-arylsulfonyl compounds, with N α,N τ-di-4-trifluorobenzenesulfonyl histamine (IId) being the best inhibitor. Compound IId is a reversible and competitive α-glucosidase inhibitor, and presented good selectivity with respect to other target enzymes, including β-glucosidase and α-amylase, and interesting predicted physicochemical properties. Docking studies have been run to postulate ligand-enzyme interactions to account for the experimental results. In vivo, compound IId produced a similar hypoglycemic effect to acarbose with half of its dose.

School-based individualised lifestyle intervention decreases obesity and the metabolic syndrome in Mexican children

BACKGROUND

Currently, there is limited evidence about effective strategies to manage childhood obesity and the metabolic syndrome in school settings. The present study aims to analyse changes in the prevalence of being overweight/obese and having the metabolic syndrome in relation to a 10-month lifestyle intervention based on individualised face-to-face sessions and parental education in school settings.

METHODS

The study sample comprised a cross-sectional sample of 96 overweight/obese Mexican children aged 6-12 years from eight schools. Clinical, anthropometric measurements and 24-h recalls were obtained during each of 13 visits. Laboratory measurements were determined at the beginning and end. The energy-reduced diet was based on dietary recommended intakes. Individualised structured daily meals and a physical activity plan, tailored-made for each child, were provided every 3 weeks at the schools. Parental attendance was required. Student's t-test, McNemar and Shapiro-Wilk tests and simple linear regression were used for the statistical analysis.

RESULTS

The prevalence of metabolic syndrome fell significantly from 44% to 16% (P < 0.01), high blood pressure fell from 19% to 0%, hypertrigliceridaemia fell from 64% to 35%, high-density lipoprotein-cholesterol ≤ 40 fell from 60% to 41%, hyperglycaemia fell from 1% to 0%, and waist circumference ≥90th percentile fell from 72% to 57%. There was a 2.84 [95% confidence interval (CI) = -4.10 to -1.58; P < 0.01] significant decrease in body mass index percentile and in body-fat percentage (95% CI = -3.31 to -1.55; P < 0.01). Of the overweight children, 32% achieved normal-weight, whereas 24% of the obese ones converted to overweight and 1% reached normal-weight. Physical activity increased 16 min/day(-1) (P = 0.02) and 2 days/week(-1) .

CONCLUSIONS

A school-setting lifestyle intervention led to a decreased prevalence of being overweight/obese and to a striking reduction in the prevalence of the metabolic syndrome in a sample of Mexican children.

Immunoradiometric assay of lipid A: a test for detecting and quantitating endotoxins of various origins

The ability to measure circulating endotoxin in various disease states has been hampered by the lack of a specific and quantitative assay. The test most commonly used has been the Limulus gelation assay, which measures an enzymatic effect of endotoxin rather than the substance itself. Based on a solid-phase immunoradiometric assay previously developed to detect the specific lipopolysaccharide from Escherichia coli 026, a similar assay has been developed for the lipid A moiety of endotoxins. The assay uses rabbit antibodies to lipid A which do not react with ketodeoxyoctonate, myristic or beta-hydroxymyristic acids, and detects lipid A obtained from endotoxins of various origins after acid hydrolysis of lipopolysaccharide. Experiments in rats given exogenous endotoxin suggest that this assay can be useful for quantitation of bacterial endotoxins in serum and for studying the pathophysiology of experimental endotoxemia.