Application Modes Affect Two Universal Adhesive Systems' Nanoleakage Expression and Shear Bond Strength.

OBJECTIVES: The aim of this study was to evaluate the shear bond strength and the nanoleakage expression of CLEARFIL Universal Bond Quick and Tetric N-Bond adhesive systems bonded to dentin. MATERIALS AND METHODS: 100 freshly extracted human premolar teeth were utilized. The teeth were sectioned to expose dentin. All dentin specimens were assigned into 4 experimental groups; 2 groups had Universal Bond Quick (Universalself group) and Tetric N-Bond (Tetricself group) applied in the self-etch mode, while 2 groups had Universal Bond Quick (Universaltotal group) and Tetric N-Bond (Tetrictotal group) applied in the total-etch mode. n = 15 for shear bond strength and n = 10 for nanoleakage experiment. One-way ANOVA and Kruskal-Wallis test were utilized to analyze the shear bond strength test and the nanoleakage expression, respectively. RESULTS: The highest significant bond strength value was recorded by the Tetricself specimens (p < 0.05) when compared to the remaining three groups. There were no statistically significant differences between the shear bond strength values recorded in the Tetrictotal, Universalself, and Universaltotal groups (p < 0.05). Both bonding systems applied in the self-etch mode (Universalself, Tetricself) had no silver nitrate deposits in the hybrid layer and the hybrid layer-adhesive interface (p < 0.001); however, both bonding systems applied in the total-etch mode (Universaltotal, Tetrictotal) had silver nitrate deposits in the hybrid layer, the hybrid layer-adhesive interface, and the bonding layer (p < 0.001). CONCLUSION: Applying the Universal Bond Quick and Tetric N-Bond in the self-etch mode exhibited better results in terms of nanoleakage expression. Universal Bond Quick showed the stability of the shear bond strength to dentin when applied using the total-etch or self-etch modes. Tetric N-Bond showed significant deterioration in bond strength when applied in the total-etch mode and exhibited the highest bond strength when applied in the self-etch mode.

Novel evaluation and treatment techniques for white spot lesions. An in vitro study.

OBJECTIVE: White spot lesions (WSLs) are commonly seen during and after orthodontic treatment. Therefore, the objective of this in vitro study was to assess the effect of 45S5-bioglass in remineralizing WSLs using cross-polarization optical coherence tomography (CP-OCT) and confirm the findings by micro-hardness test. METHODS: Ceramic orthodontic brackets were bonded to the buccal surface of 45 human premolars with Transbond XT primer followed by Transbond PLUS according to the manufacturer's instructions. Then, all specimens were varnished excluding the area of interest (AOI) around the bonded brackets, immersed in demineralizing solution and divided into three groups: BG, REM and CONT. In BG group, 15 specimens were treated with bioglass paste for 24 hours. REM group had 15 specimens stored in remineralization solution for 24 hours. CONT group had the remaining 15 specimens with no treatment. All specimens were examined under CP-OCT and tested using cross-sectional micro-hardness techniques. RESULTS: CP-OCT analysis showed that the maximum pixel value after bioglass application was significantly increased at AOI when compared to CONT and REM groups (P>.05), which was confirmed by the cross-sectional micro-hardness results (P>.05). CONCLUSION: Early enamel demineralization and remineralization can be easily and non-invasively monitored with CP-OCT. Bioglass is a potent remineralizing agent.

Diabetes detrimental effects on enamel and dentine formation.

OBJECTIVES: Understanding morphological changes and mineral content of tooth hard tissues may influence dental treatment. In this study, the effect of Type 1 Diabetes Mellitus (T1DM) on tooth structure was examined. METHODS: Experimental T1DM was induced in 3-week old male Wistar rats (n=10) by a single dose of 60mg/kg body weight of Streprozotocin. All rats were injected with calcein twice during the experiment and sacrificed at the age of 7 weeks old. Micro-computed tomography (micro-CT) was used to determine the mineral density and thickness of enamel and dentine. Also, a histomorphometery study was conducted to detect the rates of dentine mineral apposition and formation. The examined area was in the crown analogue of the rat mandibular incisor parallel to the long axis of the mesial surface of the first molar. All results were compared using Students' t-test (p<0.05). RESULTS: Results showed that the enamel and dentine thickness were significantly reduced (hypoplasia) and there was a significant reduction of the rate of dentine mineral apposition and formation, while there was no significant effect of the T1DM condition on the mineral density of enamel and dentine. CONCLUSIONS: T1DM has a detrimental influence on the formation of enamel and dentine in the early growth stage. CLINICAL SIGNIFICANCE: T1DM condition may alter treatment planning of orthodontic treatment as it is associated with decreased enamel and dentin thickness that may affect teeth size and their resistance to caries.

Isolation and identification of efficient Egyptian malathion-degrading bacterial isolates.

Bacterial isolates degrading malathion were isolated from the soil and agricultural waste water due to their ability to grow on minimal salt media amended with malathion as a sole carbon source. Efficiencies of native Egyptian bacterial malathion-degrading isolates were investigated and the study generated nine highly effective malathion-degrading bacterial strains among 40. Strains were identified by partial sequencing of 16S rDNA analysis. Comparative analysis of 16S rDNA sequences revealed that these bacteria are similar with the genus Acinetobacter and Bacillus spp. and RFLP based PCR of 16S rDNA gave four different RFLP patterns among strains with enzyme HinfI while with enzyme HaeI they gave two RFLP profiles. The degradation rate of malathion in liquid culture was estimated using gas chromatography. Bacterial strains could degrade more than 90% of the initial malathion concentration (1000 ppm) within 4 days.

Insecticidal, acaricidal and synergistic effects of soosan, Pancratium maritimum extracts and constituents.

In assessing the pesticidal activity of soosan, P. maritimum, the bulbs and leaves were extracted using acetone/ethanol & ethanol as solvents and mosquito larvae C. pipiens, as a test organism. The actone/ethanol extract of bulbs was more toxic (LC50: 25 ppm) than that of the leaves (LC50: 75 ppm). Crude alkaloids, lycorine, terpenes & sterols and fixed oil were isolated from soosan bulb. their percentages were: 0.193, 0.02, 0.13 and 3.3%, respectively. The acetone/ethanol extract showed a strong aphicidal activity to Aphis gossypii with LC50 of 0.028% followed by lycorine, soosan oil and crude alkaloids with LC50 values of 0.07, 0.28 and 0.3% respectively. Also, the acetone/ethanol extract showed high toxicity to Spodoptera littoralis 4th instar larvae, with LD50 value of 2 Mg/larva. In addition, the crude alkaloids ethanol extract and the oil of soosan bulbs showed acaricidal activity against the two spotted spider mite, Tetranychus urticae with LC50 values of 0.2, 0.36 and 1.5%, respectively. Synergism studies on the A. gosspii indicated that lycorine, the principal alkaloid of soosan bulbs, strongly synergized, the OP insecticide cyanophos and reducing its LC50 values from 120 to 48 ppm. On the other hand, the aqueous extract of soosan bulbs synergized the toxicity of actellic and permethrin in Tribolium castaneum which reduced their LC50 values from 80 to 46 ppm and from 1000 to 550 ppm, respectively. Also, ethanol and petroleum-ether extracts synergized the toxicity of reldan and permethrin, respectively, in the same insect.

Influence of the alcohol moiety of pyrethroids on their interactions with the nicotinic acetylcholine receptor.

Ten pyrethroids affected binding of [3H]perhydrohistrionicotoxin ([ 3H]H12-HTX) to the channel sites of the nicotinic acetylcholine (ACh) receptor/channel of the electric organ of the electric ray, Torpedo ocellata, and inhibited 45Ca2+ flux through the receptor's ionic channel. Most pyrethroids stimulated binding of [3H]H12-HTX to the channel sites in 30 s, in absence of carbamylcholine, with little or no effect on binding of [3H]ACh to the receptor sites, which suggests that the pyrethroids are binding to a third kind of site. However, in presence of carbamylcholine, all pyrethroids inhibited binding of [3H]H12-HTX, with esters of cyclopentenolone more potent, and generally more rapid in doing so, than esters of alpha-cyano-3-phenoxybenzyl alcohol. Changes in the acidic moiety of the pyrethroid had little effect. Kadethrin, whose alcohol moiety is 5-benzyl-3-furylmethyl, was the most potent pyrethroid in stimulating [3H]H12-HTX binding (in absence of carbamylcholine) in 30 s (18-fold) and in inhibiting it in 120 min. The pyrethroids were more potent in their modulation of [3H]H12-HTX binding at lower temperatures. Inhibition of receptor binding and receptor-regulated ion transport by concentrations of pyrethroids similar to those at which they affect nerve conduction suggests that the nicotinic ACh receptor may be an additional target for the toxic action of pyrethroids.

Allethrin interactions with the nicotinic acetylcholine receptor channel.

Interactions of the synthetic pyrethroid allethrin with the nicotinic acetylcholine (ACh) receptor/channel were studied in membranes from Torpedo electric organ. Allethrin did not inhibit binding of [3H]ACh to the receptor sites, but inhibited noncompetitively binding of [3H]perhydrohistrionicotoxin ([3H]H12-HTX) to the ionic channel sites in a dose-dependent manner. The inhibition constant (Ki) of [3H]H12-HTX binding in absence of receptor agonist was 30 micro M, while in presence of 100 micro M carbamylcholine it was 4 micro M. This inhibitory effect of allethrin had a negative temperature coefficient. The high affinity binding of allethrin to the channel sites of the nicotinic ACh-receptor may be indicative of a postsynaptic site of action for pyrethroids, in addition to their known action on the sodium channel.