Effects of enamel deproteinization with different application times on the shear bond strength of a self-etching primer: An in vitro study.

OBJECTIVE: The aim of this in vitro study was to evaluate the effects of enamel deproteinization on the shear bond strength of a self-etching primer Transbond Plus™(TBP), with different application times of sodium hypochlorite (NaOCl 5.25%), primarily and secondarily on the adhesive remnant index score. MATERIALS AND METHODS: One hundred twenty-five freshly extracted human premolars were randomly and blindly divided into five groups according to the enamel surface preparation, as follows (n=25): group 1(control): Etching with 37% phosphoric acid for 15seconds+Bonding; group 2 (control): TBP™ without NaOCl, group 3: 60seconds NaOCl+TBP™, group 4: 30seconds NaOCl+TBP™, group 5: 15seconds NaOCl+TBP™. The same composite resin was used (Transbond XT™) to bond the orthodontic metal brackets. After the immersion of the teeth in distilled water at 37°C for 24hours the shear bond strength was measured using the universal testing machine and the adhesive remnant index score (ARI) was evaluated under an optical microscope (25×). RESULTS: The mean SBS values (inMPa) of the groups were respectively: group 1: 13.03±5.36; group 2: 12.28±3.06; group 3: 12.38±4.55; group 4: 12.98±5.76; and group 5: 11.73±5.67. Enamel deproteinization increased the SBS for groups 3 and 4, but no statistically significant difference was found between the five groups (P=0.883). Group 1 showed the highest ARI scores, with 52% of the teeth retaining all the adhesive (score 3). However, for all the other groups, scores 0 and 1 were predominant, with less than half of the adhesive or no adhesive at all remaining on the teeth. CONCLUSIONS: Enamel deproteinization with sodium hypochlorite (5.25%) and the variation of its application time has no effect on the SBS of the self-etching primer Transbond Plus ™.

Occupational Exposure to Blood-Borne Pathogens among Healthcare Workers in a Tertiary Care Center in Lebanon.

OBJECTIVES: Despite numerous initiatives, occupational exposure to blood-borne pathogens (BBP) caused by percutaneous injuries or mucosal contamination remain common among healthcare workers (HCWs). These exposures were decreasing at the American University of Beirut Medical Center (AUBMC) in the previous decades. Recently, the medical center activity has been increasing with higher number of interventions performed and shorter hospital stay. Our aim was to determine the trend of incidents resulting from BBP exposures at AUBMC from 2014 till 2018 and identify whether the increase in hospital activity affected the rate of these exposures. We also aimed to assess the risk factors associated with needle stick injuries (NSIs). METHODS: A retrospective observational descriptive study of all exposures to BBPs among HCWs reported to the Environmental Health, Safety, and Risk Management department at the AUBMC between 2014 and 2018 was performed. RESULTS: There were 967 exposures reported among which 84% were due to needlesticks. Residents (40%), followed by nurses (30%), and then by attending physicians (16%) were the top three most exposed occupational groups. Half of the participants injured themselves using either a syringe or a suture needle; and mostly during or after use. Occupation and incident location were associated with NSIs. The mean BBP exposure incidence rate was 5.4 per 100 full-time employees, 65.6 per 100 bed-years, and 0.48 admission-years. The BBP exposure rate per 100 occupied beds per year decreased between 2014 and 2017 then increased in 2018 (P < 0.001). The number of BBP exposures showed a strong, though non-significant negative correlation with the average length of hospital stay (Spearman correlation coefficient = -0.9, P = 0.083). CONCLUSIONS: BBP exposure remains a serious occupational hazard. Our study shows that the BBP exposure rate per 100 occupied beds per year started decreasing during the study period before increasing again in 2018. Only the nursing department showed a consistent decrease of exposures. The occupation and incident location were found to be risk factors associated with NSIs. In addition to providing education and training, additional steps such as providing safety equipment and future interventions directed towards adjusting to higher workload should be all considered.

Effect of 2 Heat-treated Nickel-Titanium Files on Enlargement and Deformation of the Apical Foramen in Curved Canals: A Scanning Electronic Microscopic Study.

INTRODUCTION: The aim of this study was to evaluate under scanning electronic microscopy the enlargement and deformation of the apical foramen of curved mesiobuccal roots with both reciprocating and rotary single-file systems made of a newly heat-treated alloy through the use of Reciproc Blue (REC Blue; VDW, Munich, Germany) and XP-endo Shaper (XPS; FKG Dentaire, La Chaux-de-Fonds, Switzerland). METHODS: Forty mesiobuccal roots of mandibular and maxillary molars presenting a curvature ranging from 20°-40° were used in this study. The apical foramens were initially scanned with a scanning electronic microscope under 200× magnification. Roots were divided into 2 groups (n = 20): the REC Blue group instrumented with the REC Blue system and the XPS group instrumented with the XPS system. Both groups were instrumented at the foramen. The apical foramens were scanned after root canal preparation. The area, circularity, and ratio of the Feret diameters were calculated from each image. The Kolmogorov-Smirnov, Mann-Whitney, and Wilcoxon tests were used for statistical analysis (P ≤ .05). RESULTS: The area of the foramen increased significantly after canal shaping with REC Blue and XPS. The variation of the area was significantly greater with XPS. However, there were no significant differences in circularity and the ratio of the Feret diameters with both instruments. CONCLUSIONS: No transportation was found when using REC Blue and XPS. The newly heat-treated nickel-titanium alloy did not promote deformation of the apical foramen in curved canals.

Influenza vaccine and cardiac protection: a study from a tertiary care center.

Patients with heart disease (HD) are at increased risk of developing cardiac complications if they acquire the influenza virus. The objective of this study was to determine whether the influenza vaccine has a primary role in preventing newly diagnosed HD in patients who have no history of HD and who were being followed up at the American University of Beirut Medical Center (AUBMC). The study is a retrospective cohort, with 2-years follow up, which was conducted using electronic medical records between the years of 2011-2013 in a tertiary care center. All patients 60 years and older (n = 698) who have taken the flu vaccine were randomly selected from the University Health Service records (UHS) and compared to a group who has not taken the flu vaccine during the same period. The odds of developing HD among vaccinated people with cofactors are 0.97 times the odds of that among non-vaccinated. This odds ratio is not significantly different than that of people vaccinated without cofactors (OR = 1.74). The occurrence of HD in the presence of vaccination revealed a non-significant decrease trend with the increase in a number of risk factors (OR = 1.61 vs 0.97). Our results suggest that there was a non-significant difference between the effect of the vaccine for influenza on patients who had cofactors for HD and those who had not. Similarly, the effect of vaccine showed a non-significant increase in protective effect as the number of comorbidities increase. The potential effects of the vaccine may be related to the protection against flu.