Selective enamel etching: effect on marginal adaptation of self-etch LED-cured bond systems in aged Class I composite restorations

The aim of this study was to evaluate the influence of previous enamel etch and light emitting diode (LED) curing on gap formation of self-etch adhesive systems in Class I composite restorations after thermomechanical aging (TMA). Thus, on 192 human molars, a box-shaped Class I cavity was prepared maintaining enamel margins. Self-etch adhesives (Clearfil SE and Clearfil S3) were used to restore the preparation with a microhybrid composite. Before application of the adhesives, half of the teeth were enamel etched for 15 seconds with 37% phosphoric acid; the other half were not etched. For the photoactivation of the adhesives and composite, three light-curing units (LCUs) were used: one polywave (Ultra-Lume LED 5, UL) and two single-peak (FlashLite 1401, FL and Radii-cal, RD) LEDs. After this, epoxy resin replicas of the occlusal surface were made, and the specimens were submitted to TMA. New replicas were made from the aged specimens for marginal adaptation analysis by scanning electron microscopy. Data were submitted to Kruskal-Wallis and Wilcoxon tests (α=0.05). Before TMA, when enamel was etched before the application of S3, no gap formation was observed; however, there were gaps at the interface for the other tested conditions, with a statistical difference (p≤0.05). After TMA, the selective enamel etching previous to the S3 application, regardless of the LCU, promoted higher marginal adaptation compared to the other tested groups (p≤0.05). Prior to TMA, higher marginal integrity was observed, in comparison with specimens after TMA (p≤0.05). With regard to Clearfil SE and Clearfil Tri-S cured with FL, no differences of gap formation were found between before and after aging (5.3 ± 3.8 and 7.4 ± 7.5, respectively), especially when the Clearfil Tri-S was used in the conventional protocol. When cured with RD or UL and not etched, Clearfil Tri-S presented the higher gap formation. In conclusion, additional enamel etching promoted better marginal integrity for Clearfil Tri-S, showing it to be an efficient technique for Class I composite restorations. The two-step self-etch adhesive was not influenced by selective enamel etching or by the LED-curing unit.     

Bilateral supra- and infrahyoid EMG activity during eccentric jaw clenching and tooth grinding tasks in subjects with canine guidance or group function

This study compares the effect of tooth clenching and grinding on supra- and infrahyoid electromyographic (EMG) activity during different laterotrusive jaw posture tasks. The study included 30 healthy subjects with natural dentition and bilateral molar support, 15 with bilateral canine guidance and 15 with bilateral group function. Bipolar surface electrodes were located on the left and right supra- and infrahyoid muscles. EMG activity was recorded during the following tasks: A. eccentric grinding from intercuspal position to the right lateral edge-to-edge contact position; B. clenching in right edge-to-edge lateral contact position; C. concentric grinding from right lateral edge-to-edge contact position to intercuspal position. EMG activity was not significantly different between tasks on the working side, nonworking side, or between both sides, in subjects with canine guidance or group function (Wilcoxon rank-sum test). When comparing EMG activity by occlusal scheme, no significant differences were found either on the working side or the non-working side (Mann-Whitney U test). This result suggests that supra- and infrahyoid EMG activity in its predominant stabilizing role of the hyoid bone is not significantly modified by the type of laterotrusive occlusal scheme.     

Effect of substituents in the A and B rings of chalcones on antiparasite activity

Chalcones are a group of natural products with many recognized biological activities, including antiparasitic activity. Although a lot of chalcones have been synthetized and assayed against parasites, the number of structural features known to be involved in this biological property is small. Thus, in the present study, 21 chalcones were synthesized to determine the effect of substituents in the A and B rings on the activity against Leishmania braziliensis, Trypanosoma cruzi, and Plasmodium falciparum. The compounds were active against L. braziliensis in a structure-dependent manner. Only one compound was very active against T. cruzi, but none of them had a significant antiplasmodial activity. The electron-donating substituents in ring B and the hydrogen bonds at C-2′ with carbonyl affect the antiparasitic activity.     

Negative association between quantities of body fat and physical fitness of university football players

Sport Sciences for Health - The aim of the present study was to assess, analyze and correlate tests of physical abilities (acceleration and maximum speed in 30 m, Balsom agility test and...     

Diving-related fatalities: multidisciplinary,experience-based investigation

Forensic Science, Medicine and Pathology - To describe the technical characteristics of fatal diving mishaps and to elucidate the causes of death using a sequence analysis and a multidisciplinary...     

Aortic Bulge: A Possible Predictive Sign of Impending Aortoenteric Fistula

PurposeThe purpose of this study is to introduce the aortic bulge sign, a finding observed retrospectively on computed tomography prior to the acute presentation of aortoenteric fistula, and to determine its interobserver reliability.MethodsFollowing research ethics board approval, all cases of aortoenteric fistula at our institution occurring from 2011–2015 were identified retrospectively. All previous computed tomography images of patients who eventually developed aortoenteric fistula were reviewed by a single observer for the presence of a potentially predictive finding of fistulization, the aortic bulge sign. These previous images were then combined with age and sex matched controls into a case bank. Eight radiology residents and staff were instructed in observing the aortic bulge sign. These observers then reviewed the case bank in a blinded analysis to determine the interobserver reliability of this finding.ResultsFourteen cases of aortoenteric were identified. The average patient age was 70.71 years with a male-to-female ratio of 11:3. Eleven patients had previous computed tomography images available for review. With blinded analysis by multiple observers, the aortic bulge sign was identified with greater than 80% agreement in six of 11 cases (66.67%). Fleiss' kappa was calculated at k = 0.60 (95% confidence interval 0.50–0.69), corresponding to moderate-to-substantial interobserver agreement.ConclusionsThe aortic bulge sign has been retrospectively identified as a promising computed tomography finding of eventual aortoenteric fistula prior to acute presentation. Further study is required to determine the diagnostic value of this sign.