Effect of Polymerization on the Color of Resin Composites

OBJECTIVES

The initial shade of a resin-based restorative material should be the same as that after polymerization. In this study, the color changes of translucent and opaque composites from nine different brands were assessed after polymerization using a spectrophotometer and cross-polarization (CP) photography.

METHODS AND MATERIALS

Thirteen nano-hybrid (Essentia LE, GC Corp; Ceram.x Duo SphereTEC A2E/A2D, Dentsply Sirona; Harmonize A2E/A2D, Kerr Dental; IPS Empress Direct A2E/A2D, Ivoclar Vivadent; Mosaic EN/A2, Ultradent Products; Clearfil Majesty Es-2 A2E/A2D, Kuraray Noritake; Charisma Topaz A2/OL, Kulzer), two supra nano-hybrid (Estelite Asteria NE/A2B; Tokuyama), two nano-filled (Filtek Ultimate A2E/ A2D; 3M) light-curing resin composites, and one micro-hybrid (Essentia MD, GC Corp) light-curing resin composite were tested. Disc-shaped specimens (n=5) were prepared using silicone molds (12 × 5 mm) and polymerized from both sides using an LED curing light (Elipar Deepcure S, 3M) at a light intensity of 1470 mW/cm2. Measurements were performed before and 1 day after polymerization using a contact-type dental spectrophotometer (Easy Shade 5, VITA Zahnfabrik, Bad Säckingen, Germany) and a combination of CP photography and Photoshop CC software (Adobe Inc, San Jose, CA, USA). Spectrophotometry and CP photography ΔE* values were calculated; the perceptibility threshold was a ΔE* value of 1.2. VITA spectrophotometry color change scores were also calculated and evaluated.

RESULTS

The overall ΔE* values ranged between 0.34 and 12.56. Two-way analysis of variance (ANOVA) showed that color change was associated most strongly with composite brand (p<0.001), followed by shade (p=0.002). Color change (p=0.002) and degree of darkening/lightening (p<0.001) were significantly greater for dentin compared to enamel shades. Clearfil Majesty Es-2 (Kuraray Noritake) showed significant lightening, whereas all other composites showed darkening after polymerization. All composite brands presented perceptible (ΔE*≥1.2) color changes. Estelite Asteria (Tokuyama), Ceram.x Duo SphereTEC (Dentsply Sirona), and Harmonize (Kerr Dental) were considered the most reliable brands regardless of the shade. The spectrophotometry and CP photography methods were positively correlated (p<0.001). Also, CIEDE2000 and CIELCH (also referred to as CIE L*c*h) color systems were positively correlated based on the ΔE* values (p<0.001).

CONCLUSIONS

Despite improvements in the chemical composition of, and fillers for, contemporary resin-based composites (RBCs), all tested composite brands showed perceptible color change after polymerization, except for some shades. Under the conditions in this study, it is preferable to polymerize the composite during the trial phase, before identifying the most appropriate shade. CP photography in combination with Photoshop analysis appears to be a reliable and promising approach for color evaluation.

Attenuation of bleomycin induced lung fibrosis by erdosteine and inhibition of the inducible nitric oxide synthase

BACKGROUND AND OBJECTIVES

Despite advances in treatment modalities, the discovery of optimal medical therapies still remains a necessity in the management of pulmonary fibrosis.

MATERIAL AND METHODS

The experiments were performed in 35 adult Sprague Dawley rats, randomly allotted into one of five groups (n=7). The control group was treated with 1 ml/kg, 0.9 % saline; the BLM group was given a single dose of BLM (2.5 U/kg); the BLM+ER group was treated with ER (10 mg/kg/day po) for 14 days after BLM administration; the BLM+SMT group was treated with i.p injections of SMT (20 mg/kg/ day) for 14 days after BLM administration; the BLM+ER+SMT group was treated with ER and SMT for 14 days after BLM administration. At the end of day 14, the results of histopathological, biochemical, and immunohistochemical investigations were analyzed.

RESULTS

Serum TNF-α, nitrate/nitrite, and TBARS levels significantly increased in BLM group compared to control group (p < 0.001, p < 0.001 and p < 0.05 respectively). Lung tissue content of IL-6 was found to be lower in BLM+ER, BLM+SMT and BLM+ER+SMT groups compared to BLM group by immunhistochemical examinations (p < 0.01, p < 0.01 and p < 0.001, respectively). Similarly, the TNF-α reactions (p < 0.01 for each group) and NF-kB expressions were shown to be significantly different among the study groups (p < 0.05, p < 0.05 and p < 0.001, respectively).

CONCLUSION

Based on our study, ER and SMT attenuate BLM-induced pulmonary fibrosis; the combination of two agents has a greater protective efficacy against fibrosis than one alone, reducing the inflammatory markers (Tab. 2, Fig. 2, Ref. 31).

Ameliorative effect of Leflunomide on lung injury following an aspiration

BACKGROUND

We aimed to investigate the therapeutic effectiveness of leflunomide (LEF) in lung injury after an aspiration of unknown pathophysiology.

MATERIAL AND METHODS

Forty-two healthy Sprague Dawley rats were anesthetized and allocated to six experimental groups: saline (S) aspirated, S+LEF, hydrochloric acid (HCl) aspirated, HCl+LEF, formula aspirated (FOR), and FOR+LEF. The treatment groups (S+LEF, HCl+LEF, and FOR+LEF) received 20 mg/kg/day intraperitoneal (i.p.) injection of LEF for seven days. At the end of the seven days, blood and tissue samples were taken from the rats for histopathological, biochemical, and immunohistochemical examination.

RESULTS

There was a significant increase in serum levels of YKL-40, a chitinase-like protein, in the HCl group after the aspiration (p<0.01). The increase in serum YKL-40 levels decreased significantly with LEF treatment (p<0.01). There was no significant difference in serum YKL-40 levels in the FOR group compared to the control group at pretreatment and in the FOR+LEF group at post-treatment. There was a significant increase in serum thiobarbituric acid-reactive species (TBARS) values in the HCl and FOR groups compared to the control group (p=0.001 and p<0.01, respectively). In both treatment groups, the serum TBARS values significantly decreased after treatment with LEF (p=0.001 and p<0.05, respectively). There was a significant improvement in the histopathological scores, which deteriorated after the aspiration, and in the number of inducible nitric oxide synthase (iNOS)-positive cells after treatment with LEF.

Gas what: NO is not the only answer to sexual function

The ability to get and keep an erection is important to men for several reasons and the inability is known as erectile dysfunction (ED). ED has started to be accepted as an early indicator of systemic endothelial dysfunction and subsequently of cardiovascular diseases. The role of NO in endothelial relaxation and erectile function is well accepted. The discovery of NO as a small signalling gasotransmitter led to the investigation of the role of other endogenously derived gases, carbon monoxide (CO) and hydrogen sulphide (H2 S) in physiological and pathophysiological conditions. The role of NO and CO in sexual function and dysfunction has been investigated more extensively and, recently, the involvement of H2 S in erectile function has also been confirmed. In this review, we focus on the role of these three sister gasotransmitters in the physiology, pharmacology and pathophysiology of sexual function in man, specifically erectile function. We have also reviewed the role of soluble guanylyl cyclase/cGMP pathway as a common target of these gasotransmitters. Several studies have proposed alternative therapies targeting different mechanisms in addition to PDE-5 inhibition for ED treatment, since some patients do not respond to these drugs. This review highlights complementary and possible coordinated roles for these mediators and treatments targeting these gasotransmitters in erectile function/ED.

Amitriptyline overdose in emergency department of university hospital: evaluation of 250 patients

OBJECTIVE

The purpose of this study was to evaluate the patients with acute amitriptyline poisoning and investigate predictive factors for the development of life-threatening complications.

METHODS

Demographics, clinical, laboratory, and electrocardiographic (ECG) findings of 250 patients were evaluated retrospectively. Predictive parameters for the development of serious complications were studied.

RESULTS

Median age of patients was 14.6 years, of which, 70% of patients were female and 66% were in pediatric age group. The most common pathological clinical finding and laboratory abnormality were alteration of consciousness and hyponatremia. The rate of convulsive seizure, arrhythmia, and respiratory depression were 17 (6.8%), 16 (6.4%), and 11 (4.4%), respectively. These complications were more seen in pediatric patients than adults (15.8% and 1.2%). The incidence of hyponatremia was more in pediatric patients and severe poisoning groups (38.8 and 53.4%, respectively). The levels of amitriptyline and nortriptyline were significantly higher in the group with complications than the group without complications (p < 0.05). All adult patients were discharged with good prognosis. In pediatric age group, one patient was discharged with severe neurological sequelae and one patient died. QRS duration >100 ms, long corrected QT duration interval, and low Glasgow Coma Score (GCS) at admission were identified as independent risk factors for the development of life-threatening complications (odds ratio: 69.4, 1.9, and 1383, respectively; p < 0.05).

CONCLUSION

Amitriptyline poisoning may be associated with life-threatening complications, especially in pediatric age group and in patients with hyponatremia. Low GCS, presence of hyponatremia, high serum drug levels, and pathological ECG findings on admission may be helpful in predicting the development of complications and poor prognosis.

The effects of α-tocopherol on oxidative damage and serum levels of Clara cell protein 16 in aspiration pneumonitis induced by bile acids

Our aim in this study is to examine the effects of α-tocopherol (AT) on rats with aspiration pneumonitis induced with bile acids (BAs). The animals were divided in to four groups, namely saline group ( n = 7), saline + AT group ( n = 7), BA group ( n = 7), and BA + AT group ( n = 7). Saline and BA groups aspirated intratracheally with 1 ml/kg saline and 1 ml/kg bile acids, respectively. AT was given at 20 mg/kg/day dosage for 7 days to the groups. AT group was given 20 mg/kg/day AT for 7 days. Malondialdehyde (MDA), Clara cell protein 16 (CC-16), catalase (CAT), superoxide dismutase (SOD), as well as peribronchial inflammatory cell infiltration, alveolar septal infiltration, alveolar edema, alveolar exudate, alveolar histiocytes, and necrosis were evaluated. The CAT activity of the BA group was significantly lower than the saline group. In the BA + AT group, there was a significant increase in SOD and CAT activities when compared with that of the BA group. The CC-16 and MDA contents in the BA group were significantly higher than in the saline group. The CC-16 and MDA levels of the BA + AT group were significantly lower than BA group. Histopathologic changes were seen in BA group, and there was a significant decrease in the BA + AT group. In conclusion, AT might be beneficial in the treatment of aspiration pneumonitis induced by BAs because AT decreased oxidative damage and resulted in a decrease in CC-16 levels.

A study on the protective activity of kefir against gastric ulcer

BACKGROUND/AIMS

The effect of kefir on peptic ulcer disease was evaluated in an experimental model, with non-steroid anti-inflammatory drugs, together with the determination of gastric mucus secretion by quantitative digital histochemistry.

MATERIALS AND METHODS

The experimental group included 28 male albino Wistar rats. After a diet with standard rat bait for 7 days, 14 rats were fed with kefir for 7 days while the others were kept on the same diet. At the 14th day, indomethacin was injected to 7 of the rats fed on kefir and to 7 of the rats on standard rat bait. All the rats were sacrificed after 4 hours. Gastric erosion and ulceration were scored histopathologically. Mucosal mucus was quantified by image analysis, and periodic acid-Schiff stained area percentage was determined.

RESULTS

Erosion and ulceration were identified only in cases that received indomethacin. In the cases on kefir, erosion was identified in 6 cases (86%) and ulceration in 1 case. Rats fed on standard diet had erosion in 4 cases (57%) and ulceration in 3 (43%), but the difference was statistically insignificant (Mann-Whitney test, p=0.25). The stained area percentage for gastric mucus was not different between the four groups (Kruskal-Wallis test, p=0.313).

CONCLUSIONS

These findings suggest that kefir does not change gastric mucus secretion. Although statistically insignificant, as there were more cases with ulceration in cases on the rat diet, kefir might have a beneficial effect on peptic ulcer disease induced by non-steroid anti-inflammatory drug. This requires further evaluation in larger series.

Evaluation of vascular smooth muscle and corpus cavernosum on hypercholesterolemia. Is resveratrol promising on erectile dysfunction?

The aim of this study is to evaluate the effects of hypercholesterolemia in thoracic aorta (TA), mesenteric artery (MA), renal artery (RA), and corpus cavernosum (CC) isolated from cholesterol-fed rabbits. For determination of the maximum detrimental effect, vasorelaxation and vasoconstriction results of arteries and CC have been compared. Animals were fed with a diet that contained 2% w/w cholesterol and 2% w/w high cholesterol plus resveratrol (4 mg kg(-1) per day) for 6-week duration. Total cholesterol levels in the plasma were measured. Vascular and endothelial functions in RA, TA, MA, and CC were assessed by isolated tissue bath with cumulative doses of acetylcholine and sodium nitroprusside. The statistical significance of differences of groups was analyzed by means of one-way ANOVA or Student's t-test. P-values <0.05 were considered significant. There have been no significant changes on plasma total cholesterol levels between cholesterol and cholesterol + resveratrol-treated groups. Vasorelaxation responses to acetylcholine in resveratrol-treated group showed significant changes when compared with hypercholesterolemic group. No statistically significant differences were seen between non-receptor-mediated vasorelaxation responses between the three groups. Resveratrol might be an effective treatment in the prevention of atherosclerotic changes in arteries and CC. The initial effects of hypercholesterolemia on erectile dysfunction and endothelial dysfunction may be precluded with resveratrol. This protective effect may also ensure the prevention of coronary arterial diseases and renovascular diseases in hypercholesterolemic patients.

The effects of non-selective and cyclooxygenase-2-selective non-steroidal anti-inflammatory drugs on heterotopic ossification in rats

BACKGROUND

Review of the literature revealed several experimental studies on the effects of selective COX-2 inhibitors on fracture healing, but no reports were encountered regarding the effects of these compounds on experimental heterotopic bone formation, so the present study was conducted.

MATERIAL/METHODS

Thirty adult male Wistar rats were divided into three groups of ten animals each. Tibial and femoral bones were collected from the rats, cleaned and demineralized, and diaphyseal parts were implanted in muscle pouches created in the right gluteal region, one into each rat. Group 1 received DFU (5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulphonyl)phenyl-2(5H)-furanone), a highly selective COX-2 inhibitor, at a dose of 1.1 mg/kg/day. Group 2 received 2 mg/kg/day of indomethacin. The drugs were administered by oral gavage with 0.5% methyl cellulose as a delivery vehicle for eleven days, beginning on the first postoperative day. Group 3 received only methyl cellulose.

RESULTS

Thirty days after the implantation of the demineralized bone matrix, 6/10 of DFU-treated, 9/9 of the indomethacin-treated, and 8/9 of the control rats displayed new bone formation.

CONCLUSIONS

The results of this study suggest that no form of non-steroidal anti-inflammatory drug has inhibitory effects on heterotopic bone formation in rats. In our opinion, bone formation is a quite complex process that requires several events and is regulated by several factors, so further investigations other than those using non-steroidal anti-inflammatory drugs are required.

Effect of verapamil on responses to endothelin-1 in aortic rings from streptozotocin-induced diabetic rats

In this study, we investigated the constrictor responsiveness to endothelin-1 (ET-1, 10-30 n m) of aortic rings (under 1 g resting tension in Krebs-Bicarbonate solution) from 8-weeks streptozotocin (STZ, 65 mg kg-1, i.p)-induced diabetic rats and vehicle-treated control rats. The maximum ET-1-induced contraction of the aorta in diabetic rats was increased by 150%, but the EC50 of ET-1 remained unchanged. Although in both groups, verapamil reduced the constrictor responses to ET-1 (diabetic group P<0.001, control group P<0.05), there were not any significant differences between PD2 values. These results suggest that verapamil inhibits ET-1-induced Ca2+ entry through the L-type channel and this effect did not change in diabetes mellitus.