Interfacial fracture toughness of different resin cements bonded to a lithium disilicate glass ceramic

Objectives

To evaluate the effect of HF acid etching and silane treatment on the interfacial fracture toughness of a self-adhesive and two conventional resin-based cements bonded to a lithium disilicate glass ceramic.

Methods

Lithium disilicate glass ceramic discs were prepared with two different surface preparations consisting of gritblasted with aluminium oxide, and gritblasted and etched with hydrofluoric acid. Ceramic surfaces with a chevron shaped circular hole were treated by an optimized silane treatment followed by an unfilled resin and then three different resin cements (Variolink II, Panavia F2, and Multilink Sprint). Specimens were kept in distilled water at 37 °C for 24 h and then subjected to thermocycling. The interfacial fracture toughness was measured and mode of failures was also examined. Data were analysed using analysis of variance followed by T-test analysis.

Results

No statistically significant difference in the mean fracture toughness values between the gritblasted and gritblasted and etched surfaces for Variolink II resin cement was found (P > 0.05). For the gritblasted ceramic surfaces, no significant difference in the mean fracture toughness values between Panavia F2 and Variolink II was observed (P > 0.05). For the gritblasted and etched ceramic surfaces, a significantly higher fracture toughness for Panavia F2 than the other cements was found (P < 0.05).

Conclusions

The interfacial fracture toughness for the lithium disilicate glass ceramic system was affected by the surface treatment and the type of luting agent. Dual-cured resin cements demonstrated a better bonding efficacy to the lithium disilicate glass ceramic compared to the self-adhesive resin cement.

Clinical significance

The lithium disilicate glass ceramic surfaces should be gritblasted and etched to get the best bond when used with Panavia F2 and Multilink Sprint resin cements, whereas for the Variolink II only gritblasting is required. The best bond overall is achieved with Panavia F2.     

Seminal Corynebacterium strains in infertile men with and without leucocytospermia

This study aimed to identify seminal Corynebacterium strains in infertile men with and without leucocytospermia. Semen samples from 60 infertile men were allocated into two equal groups: semen samples with leucocytospermia and semen samples without leucocytospermia. Semen culture for Corynebacterium species was carried out on Columbia agar medium confirmed by Gram‐stained film and biochemical tests followed by analytical profile index biotyping and antibiotic susceptibility. Bacterial isolates were detected in 20/60 semen cultures (33.3%) as Corynebacteria, Staphylococci, Alpha haemolytic streptococci and E. coli. In all, 12/60 (20%) had Corynebacterium positive semen culture, whereas C. seminal was the major isolated species followed by C. amycolatum, C. jekium and C. urealyticum. There was nonsignificant difference between patients with/without Corynebacterium positive culture regarding sperm concentration and normal sperm morphology; however, in positive cultures sperm motility was significantly lower compared with negative cultures. Antimicrobial sensitivity among Corynebacteria strains was highest for vancomycin, rifampicin then imipenem, ampicillin + sulbactam, ciprofloxacin. It is concluded that positive semen cultures for different Corynebacteria species were demonstrated in infertile men, whereas Corynebacterium seminale was the most common isolated species. Vancomycin, rifampicin then imipenem and ampicillin + sulbactam are recommended as sensitive antibiotics.     

Recovery of Enterococcus faecalis from cheese in the oral cavity of healthy subjects

INTRODUCTION: Enterococci are rarely found in the healthy human oral cavity, yet they are strongly associated with filled root canals. The origin of these enterococci remains unknown. Our hypothesis is that they are transient food-born colonizers under healthy conditions. This pilot study reinvestigated the prevalence of enterococci in the oral cavity of healthy volunteers, screened cheese samples for enterococci and investigated colonization of the oral cavity after ingestion of an enterocci-positive cheese. METHOD: Concentrated oral rinse samples were collected from a cohort of 50 dental students and proved negative for viable enterococci. Twenty cheese samples were obtained from local supermarkets. Enterococci were cultured and identified using standard methods. RESULTS: Viable enterococci were detected in one of five specimens of Swiss Tilsiter, three of five samples of French soft cheese, one of five Mozzarella samples and one of five Feta samples. Eight volunteers from the cohort consumed 10 g of a cheese with high Enterococcus faecalis load. Oral rinse samples were collected before and 1, 10 and 100 min after cheese ingestion. One minute after ingestion, a median of 5,480 E. faecalis colony-forming units was recovered from the oral rinse samples. Bacterial counts were reduced after 10 min, had dropped after 100 min to levels that were significantly (P < 0.005) different from the 1-min and 10-min scores and were below the detection limit after 1 week. CONCLUSIONS: These findings suggest that colonization of the healthy oral cavity by enterococci is transitional, but at the same time add weight to our hypothesis that enterococcal root canal infections could be food-borne.     

Evaluation of the effect of acetazolamide versus mannitol on cisplatin-induced nephrotoxicity,a pilot study

Background Cisplatin-induced nephrotoxicity still occurs despite the intensive hydration approach adapted to prevent its occurrence. Objective Evaluation of the effect of acetazolamide (ACTZ) on minimizing cisplatin-induced nephrotoxicity compared to mannitol when added to hydration regimen. Setting Nasser Institute Cancer Center (NICC), Cairo, Egypt. Method A total of 35 patients planned to receive cisplatin were divided into two groups: 20 patients received mannitol and 15 patients received ACTZ. Both groups received standard hydration measures as well for prevention of cisplatin-induced nephrotoxicity. Main outcome measure Patients’ kidney function was assessed using serum creatinine, creatinine clearance and blood urea nitrogen. Kidney injury was assessed using RIFLE criteria. Patients’ liver function tests and hematological parameters were also monitored. Results Patients in the mannitol group showed higher risk of developing kidney injury (30%) whereas those in the ACTZ group showed lower risk (8.9%), relative risk (RR) 0.269, 95% CI 0.108–0.815. No statistically significant difference occurred between the two groups concerning liver function tests or hematological parameters. Conclusion Use of ACTZ in addition to intensive hydration may have more beneficial effect on minimizing cisplatin-induced nephrotoxicity compared to mannitol plus intensive hydration approach. A large multicenter randomized clinical trials is recommended to confirm study results and to assess effect of ACTZ on tumor response.     

Validity of urine neutrophile gelatinase-associated lipocalin in children with primary vesicoureteral reflux

International Urology and Nephrology - Vesicoureteral reflux (VUR) is the most common congenital urinary tract abnormality in children. The objective of this study was to evaluate the diagnostic...     

Methanolic extract of Chlorella vulgaris protects against sodium nitrite-induced reproductive toxicity in male rats

The current study aimed to investigate the protective potential of Chlorella Vulgaris (CV) extract against the reproductive dysfunction induced by sodium nitrite toxicity. Forty-five male Wistar albino rats were assigned into five groups (n = 9). Control group received normal saline orally for 3 months, CV-treated: administered CV extract (70 mg/kg.BW) orally for 3 months, sodium nitrite-treated: received sodium nitrite (80 mg/kg.BW) orally for 3 months, co-treated: simultaneously received CV along with sodium nitrite treatment, orally, daily for 3 months, and CV-pre-treated: pre-treated with CV extract for 4 weeks followed by simultaneous treatment with sodium nitrite and CV extract for additional 8 weeks. Treatment with sodium nitrite significantly decreased serum testosterone and follicle-stimulating hormone concentrations, sperm count, motility, and viability. Besides, it decreased testicular superoxide dismutase and glutathione peroxidase activities while increased malondialdehyde concentration. This effect of sodium nitrite was associated with degenerative, necrotic, vascular, and inflammatory changes in testicular tissues. Treatment of sodium nitrite-intoxicated rats with CV in co-treated and pre-treated groups significantly prevented sodium nitrite-induced alterations of sperm parameters, hormonal concentrations, testicular oxidative–antioxidant status, and histological architecture. This study indicates that CV extract ameliorates the reproductive dysfunction induced by sodium nitrite toxicity via improving reproductive hormonal levels and testicular antioxidant activities.     

Water intake and risk of type 2 diabetes: A systematic review and meta-analysis of observational studies

Background and aimsThe association of water intake with type 2 diabetes mellitus (T2DM) is still unclear. Therefore, the aim of this systematic review and meta-analysis was to synthesize the knowledge about the relationship between water intake and the risk of T2DM.MethodsWe conducted a systematic search in PubMed and Scopus up to June 2018 for observational studies. Risk ratios (RR)s and 95% confidence intervals (95% CI)s were calculated and fixed effects models were used.ResultsOverall, 6 studies were included in the meta-analyses. There was an inverse relationship between water intake and risk of T2DM (RR: 0.94; 95% CI: 0.91–0.97, P < 0.001) with low heterogeneity (I2 = 24%, P = 0.24).ConclusionOur findings indicated that the intake of water was correlated with reduced risk of type 2 diabetes in women and men. These results support the current recommendations of water intake as an inseparable part of a diet with the lowest risk of diabetes mellitus.