To Evaluate the Effect of Various Surface Treatments on the Shear Bond Strength of Three Different Intraoral Ceramic Repair Systems: An In Vitro Study

Fractures of metal-ceramic restoration pose an esthetic and functional dilemma both for patient and the dentist. Intraoral repair systems eliminate the remake and removal of restoration. Many intraoral repair materials and surface treatments are available to repair intraorally fractured metal-ceramic restoration. Bond strength data of various materials and specific technique used for repair are necessary for predicting the success of a given repair system. This study evaluated the shear bond strength of three different intraoral repair systems for metal-ceramic restorations applied on exposed metal and porcelain surface. One hundred and twenty metal discs (20 mm in diameter × 0.7 mm thick) were fabricated with nickel–chromium alloy (Mealloy, Dentsply, USA). Feldspathic porcelain (Duceram, Degudent, Germany) were applied over one test surface of the discs in the thickness of 1.8 mm followed by conventional firing. The defect, which simulates clinical failures were created in 1/4th area of the metal-ceramic discs. The metal-ceramic discs samples were divided into ceramic substrate (Group I, n = 60) and metal substrate (Group II, n = 60), according to the defect location. Then, samples of ceramic substrate (Group I) and metal substrate (Group II) were subdivided into A, B according to the surface treatments (A; roughening with diamond bur and B; abraded with 50 μ Al₂O₃) and repaired with one of the intraoral repair systems tested (a. Ceramic repair system, Ivoclar Vivadent; b. Clearfil repair system, Kurary, c; Porcelain repair system, 3 M ESPE). All the repaired samples were stored in distilled water at 37 °C for 24 h. After thermocycling at 6–60° C, all the samples were stored at 37 °C for additional 7 days. Shear bond strength of all the samples were calculated by using Universal testing machine. The mean shear bond strength values for the group I (A/B) were as follows: Ceramic repair system (9.47 ± 1.41/14.03 ± 2.54 MPa), Clearfil repair system (14.03 ± 2.32/14.64 ± 2.28 MPa), and Porcelain repair system (14.41 ± 3.96/14.86 ± 3.10 MPa). The mean shear bond strength values for the group II (A/B) were as follows: Ceramic repair system (9.42 ± 1.44/18.61 ± 2.60 MPa), Clearfil repair system (14.44 ± 3.23/14.98 ± 2.73 MPa), and Porcelain repair system (11.86 ± 2.24/13.24 ± 2.72 MPa). Air abrasion with 50 μm aluminum oxide particles is the preferred surface treatment. Porcelain repair system showed the highest shear bond with air abrasion for ceramic substrate and for metal substrate Ceramic repair system showed the highest bond strength with air abrasion as a surface treatment. This study suggest that the three repair systems tested are adequate for intraoral chairside repair of metal-ceramic restoration when air abrasion is used for surface treatment of the substrate (Ceramic repair system, Ivoclar Vivadent, Germany; Clearfil repair system, Kurary, Japan; Porcelain repair system, 3M ESPE, Germany).     

Inhibition of HA Synthase 3 mRNA Expression, with a Phosphodiesterase 3 Inhibitor, Blocks Lung Injury in a Septic Ventilated Rat Model

Low-molecular-weight hyaluronan produced by hyaluronan synthase 3 (HAS3) has been shown to play a role in acute lung injury secondary to high-tidal-volume ventilation. Phosphodiesterase 3 inhibitors have been shown to decrease HAS3 expression. We hypothesized that low-molecular-weight hyaluronan (LMW HA) produced by HAS3 mediates LPS-induced lung injury in the mechanically ventilated rat and that milrinone (MIL), by blocking HAS3 mRNA expression, would prevent the injury. Rats were randomized to four groups: controls with mechanical ventilation at 7 cc/kg MV, MV+LPS, MV+MIL, and MV+LPS+MIL. Rats were intubated and ventilated without PEEP for 4 h. Lipopolysaccharide (LPS) (1 mg/kg) was infused into the arterial line 1 h prior to MV. MIL 10 μg/kg/min (or an equivalent volume of saline) was infused through the venous line at the beginning of MV. Bronchoalveolar lavage fluid (BAL) was collected after 4 h of ventilation and lungs were saved for histopathology. LPS significantly increased neutrophil infiltration and protein concentration in the BAL and augmented lung injury score on histology. MIL significantly lowered alveolar protein and neutrophil infiltration as well as lung injury in response to LPS. Furthermore, MIL decreased the mRNA expression for HAS3 and MIP2 in lung tissue and decreased the protein content in BAL. MIL, a commonly used inotropic agent, inhibited LPS-induced lung inflammation and lung injury in mechanically ventilated rats. The anti-inflammatory properties of MIL may be mediated by inhibition of HAS3 and/or MIP2 and could be beneficial in the treatment of sepsis.     

Human ROBO1 regulates interaural interaction in auditory pathways

In rodents, the Robo1 gene regulates midline crossing of major nerve tracts, a fundamental property of the mammalian CNS. However, the neurodevelopmental function of the human ROBO1 gene remains unknown, apart from a suggested role in dyslexia. We therefore studied axonal crossing with a functional approach, based on magnetoencephalography, in 10 dyslexic individuals who all share the same rare, weakly expressing haplotype of the ROBO1 gene. Auditory-cortex responses were recorded separately to left- and right-ear sounds that were amplitude modulated at different frequencies. We found impaired interaural interaction that depended on the ROBO1 in a dose-dependent manner. Our results indicate that normal crossing of the auditory pathways requires an adequate ROBO1 expression level.     

Cerebral magnetic fields to lingual stimulation.

We recorded cerebral magnetic fields to electric stimulation of the tongue in 7 healthy adults. The two main deflections of the response peaked around 55 msec (P55m) and 140 msec (N140m). During both of them the magnetic field pattern, determined with a 7- or 24-channel SQUID magnetometer, suggested a dipolar current source. The topography of P55m can be explained by a tangential dipole at the first somatosensory cortex (SI) in the posterior wall of the central sulcus. The equivalent source of N140m is, on average, about 1 cm lateral to the source of P55m. The reported method allows non-invasive determination of the cortical tongue representation area.     

Understanding the current sexual health service provision for mental health consumers by nurses in mental health settings: Findings from a Survey in Australia and England

Nurses in mental health settings avoid talking to consumers about sexual health concerns. It is unclear whether this avoidance prevents the provision of sexual healthcare. The present study gathered information about how mental health nurses respond to sexual health issues within their routine practice, what issues they address, and their view on their role in promoting sexual health for consumers. A cross‐sectional study using an electronic survey questionnaire, originally generated from a previous study in the united kingdom, was employed. The study occurred in four National Health Service Trusts in England and a national call for participants in Australia. Participants were nurse clinicians (n = 303) who self‐selected by completing surveys available via email and newsletters containing links to the survey. The results demonstrated that mental health nurses do not routinely include sexual health in their practice and are poorly prepared in knowing what to do with a sexual health issue, and what services to assist consumers to use. In conclusion, it has been well established in the literature that mental health consumers experience high sexual health needs that potentially impact on health and recovery. Mental health nurses are ideally placed to promote sexual health and refer consumers to sexual health and family planning services. Training to improve the confidence and responsiveness of mental health nurses to sexual health is an urgent need.