Effect of bleaching on shear bond strength of composite resin to bovine enamel using three bonding agents

In many studies reduction in bond strength of bleached enamel has been pointed out. The decrease in bond strength raised concern in cosmetic dentistry. However, there is little information about the effects of bleaching, on reduction of enamel bond strength in new bonding systems. This study aimed to investigate the effects of three dental bonding agents on shear bond strength of a composite to bleached enamel. In this in vitro study, sixty intact bovine mandibular incisors were collected and randomly divided into six groups [n=10]. In group A, the facial enamel was etched with 35% phosphoric acid gel, then a single layer of bonding agent [SingleBond, 3M, ESPE] was applied and light-cured for 40 seconds by a light-curing device [ColtoluxII colten] with 400 mw/cm[2] light intensity according to the manufacturer's instructions . In group B: after etching of enamel surfaces, Clearfil SE-Bond [Kuraray Medical Inc.] was used. In group C: after etching of enamel surface, Clearfil S3 Bond [Kuraray, Medical Inc.] was used. In groups D, E, and F 35% carbamide peroxide [Opalescence, Ultradent Products Inc.] was applied on the enamel surfaces for 5 hours according to the manufacturer's recommendations. Afterwards the specimens were rinsed thoroughly with distilled water for 60 seconds and dried with compressed air. Immediately after bleaching, bonding regimes similar to groups A, B, and C were carried out in groups D, E, and F, respectively. Then, cylinders of hybrid composite were bonded to the facial enamel surface of all specimens, using 3 dental bonding agents. After 24 hours, the specimens were thermocycled [5-55°C, l000cycles], and then subjected to shear bond testing by a universal machine Zwick [Zo20, Germany]. The data were analyzed by one- and two-way ANOVA and post hoc tests. All statistical tests were performed with SPSS version 11. The mean shear bond strength of SingleBond to bleached and unbleached enamel was 8.36 +/- 3.30 and 20.17 +/- 6.52 MPa, respectively. For Clearfil SE bond, bleached enamel exhibited bond strengths of 12.25 +/- 6.61Mpa and unbleached enamel exhibited a bond strength value of 17.66 +/- 5.82 Mpa. The bond strength for Clearfil S3 bond was 6.66 +/- 2.57 Mpa to bleached andl0.40 +/- 3.65Mpa to unbleached enamel. Shear bond strength of hybrid composite to bleached enamel in three experimental groups decreased but this reduction was not statistically significant for Clearfil SE bond

effect of some avian pox vaccines on the immune response of Turkey vaccinated with fowl cholera

Live attenuated fowl cholera; fowl pox turkeys to fowl cholera vaccine. and pigeon pox vaccines were used to vaccinate turkey in a mutual manner. Six groups of turkeys [20 birds/group] were used. The first group was vaccinated with live attenuated fowl cholera and fowl pox vaccines via the wing web and feather follicle respectively. The second group was vaccinated with fowl cholera and pigeon pox vaccine, while the third group was vaccinated with fowl pox alone. The fourth group was vaccinated with pigeon pox vaccine alone and the fifth group was vaccinated with live attenuated fowl cholera vaccine alone. The sixth group was kept as unvaccinated control. The results of indirect haemagglutination test [IHA] and ELISA revealed a significant increase in Pasteurella multocida antibody titers between group [1], group [2] and group [5]. It could be concluded that the use of the pox vaccines enhance the immune response of vaccinate turkey in a mutual manner

Acceptability of injectable contraceptives and causes of dropouts in Mansoura University hospital

A clinical trial was carried out in which DMPA [150 mg/84 days for one year] was administered to 150 cases. Nor-Ethisterone enanthate [200 mg/56 days for one year]was administered to 150 women. Both injectables have proved popular and highly effective for prevention of pregnancy. Continuation rates for DMPA [77.3%] and NET-EN [63.3%] were high. This is due to proper counselling and strict follow-up. Dropouts due to non-medical causes were high in both groups [50% among DMPA dropouts and 70.9% among NET-EN dropouts]. Medical causes were the second common reason for dropouts in our study. Menstrual irregularities were not the main cause for discontinuation. Amenorrhea was more acceptable to our women

Menstrual problems among DMPA and NET-EN users in Dakahlia governorate

Menstrual side-effects among 300 women using injectable contraseptives in Mansoura University Hospital for one year were studied. Disruption of the menstrual cycles [bleeding problems and amenorrhoea] among DMPA and NET-EN users were recorded. Periodic vaginal bleeding approximating that of normal cycles was reported in 79.4% and 82.1% among DMPA and NET-EN users respectively. We can conclude that to some women injectable contraception is a reliable and tolerable method. Disruption of the menstrual cycle is not a major problem as long potential users are properly counselled and are serious in using such method of fertility control