Salivary Contamination and Decontamination: Bond Strength to Dentin of Primary and Permanent Teeth

Aim: To evaluate the effects of salivary contamination and decontamination on bond strength of two one-step adhesives to primary and permanent dentin. Methods: Dentin specimens were prepared from extracted primary and permanent molars (210 of each) and were distributed to seven groups (n=15/group/molar type) for each adhesive (Xeno V+ and Scotchbond Universal): no saliva contamination (control); saliva contamination before or after light-curing of the adhesives followed either by air-drying, by rinsing with water and air-drying, or by rinsing with water, air-drying and reapplication of the adhesives. Resin composite was applied and the specimens were stored for 24h (37°C, 100% humidity). Then, shear bond strength (SBS) was measured and data analyzed with nonparametric ANOVA and Wilcoxon rank sum tests. Results: Saliva contamination reduced SBS of Xeno V+, the reduction being more pronounced when contamination occurred before light-curing than after. In both situations, decontamination involving reapplication of the adhesive restored SBS. Saliva contamination had no significant effect on Scotchbond Universal. There were no differences in SBS between primary and permanent teeth. Conclusion: Saliva contamination reduced SBS of Xeno V+, but not of Scotchbond Universal. SBS was restored when contaminated dentin was rinsed with water and air-dried followed by reapplication of the adhesive.

Effect of Salivary Contamination and Decontamination on Bond Strength of Two One-Step Self-Etching Adhesives to Dentin of Primary and Permanent Teeth

Purpose: To evaluate the effects of human saliva contamination and two decontamination procedures at different stages of the bonding procedure on the bond strength of two one-step self-etching adhesives to primary and permanent dentin. Materials and Methods: Extracted human primary and permanent molars (210 of each) were ground to mid-coronal dentin. The dentin specimens were randomly divided into 7 groups (n = 15/group/molar type) for each adhesive (Xeno V+ and Scotchbond Universal): no saliva contamination (control); saliva contamination before or after light curing of the adhesives followed by air drying, rinsing with water spray/air drying, or by rinsing with water spray/air drying/reapplication of the adhesives. Resin composite (Filtek Z250) was applied on the treated dentin surfaces. The specimens were stored at 37°C and 100% humidity for 24 h. After storage, shear bond strength (SBS) was measured and data analyzed with nonparametric ANOVA followed by exact Wilcoxon rank sum tests. Results: Xeno V+ generated significantly higher SBS than Scotchbond Universal when no saliva contamination occurred. Saliva contamination reduced SBS of Xeno V+, with the reduction being more pronounced when contamination occurred before light curing than after. In both situations, decontamination involving reapplication of the adhesive restored SBS. Saliva contamination had no significant effect on Scotchbond Universal. There were no differences in SBS between primary and permanent teeth. Conclusion: Rinsing with water and air drying followed by reapplication of the adhesive restored bond strength to saliva-contaminated dentin.

Synthesis of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide - a tailor-made photoinitiator for dental adhesives

Because of the poor solubility of the commercially available bisacylphosphine oxides in dental acidic aqueous primer formulations, bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide (WBAPO) was synthesized starting from 3-(chloromethyl)-2,4,6-trimethylbenzoic acid by the dichlorophosphine route. The substituent was introduced by etherification with 2-(allyloxy)ethanol. In the second step, 3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoic acid was chlorinated. The formed acid chloride showed an unexpected low thermal stability. Its thermal rearrangement at 180 ° C resulted in a fast formation of 3-(chloromethyl)-2,4,6-trimethylbenzoic acid 2-(allyloxy)ethyl ester. In the third step, the acid chloride was reacted with phenylphosphine dilithium with the formation of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine, which was oxidized to WBAPO. The structure of WBAPO was confirmed by ¹H NMR, ¹³C NMR, ³¹P NMR, and IR spectroscopy, as well as elemental analysis. WBAPO, a yellow liquid, possesses improved solubility in polar solvents and shows UV-vis absorption, and a high photoreactivity comparable with the commercially available bisacylphosphine oxides. A sufficient storage stability was found in dental acidic aqueous primer formulations.

Bonding of simplified adhesive systems to caries-affected dentin of primary teeth.

PURPOSE To evaluate the bonding of simplified adhesive systems to sound and caries-affected dentin of primary teeth with microtensile (µTBS) and nanoleakage (NL) tests. MATERIALS AND METHODS Occlusal cavities were prepared in 36 sound second primary molars. Half of the specimens were submitted to pH cycling to simulate caries-affected dentin. Teeth were randomly restored with one of three materials: the etch-and-rinse adhesive system Adper Single Bond 2 (SB), the two-step self-etching adhesive system Adper SE Plus (SE), and the one-step self-etching adhesive system Adper Easy One (EASY). After storage for 24 h, specimens with cross-sectional areas of 0.8 mm2 were prepared for microtensile testing (1 mm/min). One stick from each tooth was immersed in silver nitrate solution (24 h) and allowed to develop for 8 h in order to score the nano leakage with SEM. The fracture pattern was evaluated using a stereomicroscope (400X). The µTBS means were analyzed by two-way ANOVA and Tukey's post-hoc test. For NL, the Kruskal- Wallis and Mann-Whitney tests were used (α < 0.05). RESULTS SB (35.5 ± 3.5) showed the highest µTBS value to sound dentin, followed by EASY (26.3 ± 1.9) and SE (18.2 ± 6.5) (p < 0.05). No difference among materials was observed for caries-affected dentin (SB: 17.8 ± 4.2; SE: 13.9 ± 3.2; EASY: 14.4 ± 4.2, p > 0.05). For all groups, adhesive/mixed fracture prevailed. Caries affected dentin promoted silver nitrate uptake into the adhesive interface; however, with SE, the nano leakage was more pronounced than in the other adhesive systems, even in sound dentin. CONCLUSION Caries-affected dentin negatively influences the bond strength and nano leakage of the two-step etch-and-rinse and one-step self-etching adhesive systems tested in primary teeth.

Quantitative 1-Step DNA Methylation Analysis with Native Genomic DNA as Template

DNA methylation analysis currently requires complex multistep procedures based on bisulfite conversion of unmethylated cytosines or on methylation-sensitive endonucleases. To facilitate DNA methylation analysis, we have developed a quantitative 1-step assay for DNA methylation analysis.

Observation of ventilation-induced Spo(2) oscillations in pigs: first step to noninvasive detection of cyclic recruitment of atelectasis?

High arterial partial oxygen pressure (Pao(2)) oscillations within the respiratory cycle were described recently in experimental acute lung injury. This phenomenon has been related to cyclic recruitment of atelectasis and varying pulmonary shunt fractions. Noninvasive detection of Spo(2) (oxygen saturation measured by pulse oximetry) as an indicator of cyclic collapse of atelectasis, instead of recording Pao(2) oscillations, could be of clinical interest in critical care. Spo(2) oscillations were recorded continuously in three different cases of lung damage to demonstrate the technical feasibility of this approach. To deduce Pao(2) from Spo(2), a mathematical model of the hemoglobin dissociation curve including left and right shifts was derived from the literature and adapted to the dynamic changes of oxygenation. Calculated Pao(2) amplitudes (derived from Spo(2) measurements) were compared to simultaneously measured fast changes of Pao(2), using a current standard method (fluorescence quenching of ruthenium). Peripheral hemoglobin saturation was capable to capture changes of Spo(2) within each respiratory cycle. For the first time, Spo(2) oscillations due to cyclic recruitment of atelectasis within a respiratory cycle were determined by photoplethysmography, a technology that can be readily applied noninvasively in clinical routine. A mathematic model to calculate the respective Pao(2) changes was developed and its applicability tested.

One-Step (18)F-Labeling of Carbohydrate-Conjugated Octreotate-Derivatives Containing a Silicon-Fluoride-Acceptor (SiFA): In Vitro and in Vivo Evaluation as Tumor Imaging Agents for Positron Emission Tomography (PET)

The synthesis, radiolabeling, and initial evaluation of new silicon-fluoride acceptor (SiFA) derivatized octreotate derivatives is reported. So far, the main drawback of the SiFA technology for the synthesis of PET-radiotracers is the high lipophilicity of the resulting radiopharmaceutical. Consequently, we synthesized new SiFA-octreotate analogues derivatized with Fmoc-NH-PEG-COOH, Fmoc-Asn(Ac?AcNH-?-Glc)-OH, and SiFA-aldehyde (SIFA-A). The substances could be labeled in high yields (38 ± 4%) and specific activities between 29 and 56 GBq/?mol in short synthesis times of less than 30 min (e.o.b.). The in vitro evaluation of the synthesized conjugates displayed a sst2 receptor affinity (IC?? = 3.3 ± 0.3 nM) comparable to that of somatostatin-28. As a measure of lipophilicity of the conjugates, the log P(ow) was determined and found to be 0.96 for SiFA-Asn(AcNH-?-Glc)-PEG-Tyr³-octreotate and 1.23 for SiFA-Asn(AcNH-?-Glc)-Tyr³-octreotate, which is considerably lower than for SiFA-Tyr³-octreotate (log P(ow) = 1.59). The initial in vivo evaluation of [¹?F]SiFA-Asn(AcNH-?-Glc)-PEG-Tyr³-octreotate revealed a significant uptake of radiotracer in the tumor tissue of AR42J tumor-bearing nude mice of 7.7% ID/g tissue weight. These results show that the high lipophilicity of the SiFA moiety can be compensated by applying hydrophilic moieties. Using this approach, a tumor-affine SiFA-containing peptide could successfully be used for receptor imaging for the first time in this proof of concept study.

The shock index and the simplified PESI for identification of low-risk patients with acute pulmonary embolism

We compared the test characteristics of the shock index (SI) and the simplified pulmonary embolism severity index (sPESI) for predicting 30-day outcomes in a cohort of 1,206 patients with objectively confirmed pulmonary embolism (PE). The primary outcome of the study was all-cause mortality. The secondary outcome was nonfatal symptomatic recurrent venous thromboembolism (VTE) or nonfatal major bleeding. Overall, 119 (9.9%) out of 1,206 patients died (95% CI 8.2-11.5%) during the first month of follow-up. The sPESI classified fewer patients as low-risk (369 (31%) out of 1,206 patients, 95% CI 28-33%) compared to the SI (1,024 (85%) out of 1,206 patients, 95% CI 83-87%) (p<0.001). Low-risk patients based on the sPESI had a lower 30-day mortality than those based on the SI (1.6% (95% CI 0.3-2.9%) versus 8.3% (95% CI 6.6-10.0%)), while the 30-day rate of nonfatal recurrent VTE or major bleeding was similar (2.2% (95%CI 0.7-3.6%) versus 3.3% (95%CI 2.2-4.4%)). The net reclassification improvement with the sPESI was 13.4% (p = 0.07). The integrated discrimination improvement was estimated as 1.8% (p<0.001). The sPESI quantified the prognosis of patients with PE better than the SI.

Cardiac troponin testing and the simplified Pulmonary Embolism Severity Index. The SWIss Venous ThromboEmbolism Registry (SWIVTER)

A low simplified Pulmonary Embolism Severity Index (sPESI), defined as age ≤80 years and absence of systemic hypotension, tachycardia, hypoxia, cancer, heart failure, and lung disease, identifies low-risk patients with acute pulmonary embolism (PE). It is unknown whether cardiac troponin testing improves the prediction of clinical outcomes if the sPESI is not low. In the prospective Swiss Venous Thromboembolism Registry, 369 patients with acute PE and a troponin test (conventional troponin T or I, highly sensitive troponin T) were enrolled from 18 hospitals. A positive test result was defined as a troponin level above the manufacturers assay threshold. Among the 106 (29%) patients with low sPESI, the rate of mortality or PE recurrence at 30 days was 1.0%. Among the 263 (71%) patients with high sPESI, 177 (67%) were troponin-negative and 86 (33%) troponin-positive; the rate of mortality or PE recurrence at 30 days was 4.6% vs. 12.8% (p=0.015), respectively. Overall, risk assessment with a troponin test (hazard ratio [HR] 3.39, 95% confidence interval [CI] 1.38-8.37; p=0.008) maintained its prognostic value for mortality or PE recurrence when adjusted for sPESI (HR 5.80, 95%CI 0.76-44.10; p=0.09). The combination of sPESI with a troponin test resulted in a greater area under the receiver-operating characteristic curve (HR 0.72, 95% CI 0.63-0.81) than sPESI alone (HR 0.63, 95% CI 0.57-0.68) (p=0.023). In conclusion, although cardiac troponin testing may not be required in patients with a low sPESI, it adds prognostic value for early death and recurrence for patients with a high sPESI.

A comparison of the original and simplified Pulmonary Embolism Severity Index

The Pulmonary Embolism Severity Index (PESI) is a validated clinical prognostic model for patients with pulmonary embolism (PE). Recently, a simplified version of the PESI was developed. We sought to compare the prognostic performance of the original and simplified PESI. Using data from 15,531 patients with PE, we compared the proportions of patients classified as low versus higher risk between the original and simplified PESI and estimated 30-day mortality within each risk group. To assess the models' accuracy to predict mortality, we calculated sensitivity, specificity, and predictive values and likelihood ratios for low- versus higher-risk patients. We also compared the models' discriminative power by calculating the area under the receiver-operating characteristic curve. The overall 30-day mortality was 9.3%. The original PESI classified a significantly greater proportion of patients as low-risk than the simplified PESI (40.9% vs. 36.8%; p<0.001). Low-risk patients based on the original and simplified PESI had a mortality of 2.3% and 2.7%, respectively. The original and simplified PESI had similar sensitivities (90% vs. 89%), negative predictive values (98% vs. 97%), and negative likelihood ratios (0.23 vs. 0.28) for predicting mortality. The original PESI had a significantly greater discriminatory power than the simplified PESI (area under the ROC curve 0.78 [95% CI: 0.77-0.79] vs. 0.72 [95% CI: 0.71-0.74]; p<0.001). In conclusion, even though the simplified PESI accurately identified patients at low-risk of adverse outcomes, the original PESI classified a higher proportion of patients as low-risk and had a greater discriminatory power than the simplified PESI.