Ceramic restorations with resin-based adhesive systems have been the focus of recent attention in clinical dentistry. Yttrium-oxide-partially-stabilized zirconia (YPSZ) ceramics have optimized physical properties and exhibit favorable fracture toughness, though their bonding properties are problematic. Although functional phosphate monomers and silica-coating by tribochemical modification were expected to improve the bonding properties between YPSZ ceramics and resin-based adhesives, these two methods remain controversial. This study evaluated the efficiency of silica-coating by tribochemical modification of YPSZ ceramics. The application of phosphate monomer and a silane coupling agent on silica-coated YPSZ was also investigated. The silica-coating of YPSZ ceramics by tribochemical modification was not efficient, given the higher mechanical toughness of the densely sintered ceramics. Stable shear bond strength was achieved on silica-coated YPSZ ceramics with the cooperative interaction of phosphate monomer and silane coupling.

The dentin bonding efficacies of two commercial dentin bonding systems and experimental self-etching dentin primers composed of methacryloxyethyl hydrogen phenyl phosphate (Phenyl-P) and either hydroxyethyl methacrylate (HEMA) or glyceryl methacrylate (GM, 2,3-dihydroxypropyl methacrylate) were examined. The wall-to-wall polymerization contraction gap width of a commercial light-activated resin composite in a cylindrical dentin cavity and the tensile bond strength to a flat dentin surface were measured. Changes in dentin hardness were determined by Micro Vickers Hardness measurement, and an SEM observation was performed after priming. Formation of a contraction gap was completely prevented by the application of Phenyl-P diluted in HEMA or GM solution combined with a commercial dentin bonding agent, although gap formation was evident in nearly half of the specimens with both commercial dentin bonding systems. The mean tensile bond strengths of the tested groups varied from 16.3 to 20.7 MPa, and there were no significant differences between groups. Based on the measurement of Micro Vickers Hardness and SEM observation after priming, a slight reduction in dentin hardness was observed. However, this reduction in dentin hardness due to self-etching priming did not significantly correlate with either contraction gap width or tensile bond strength.

The aim of the present study was to evaluate the bonding durability of resin-based luting cement to partially stabilized tetragonal zirconia (Y-TZP) achieved by combination treatment of tribochemical (TBC) treatment and two different phosphate acid ester monomers. Two phosphate acid ester monomers (EP: Epricord opaque primer, AZ: AZ primer) were applied to each surface modification followed by application of resin-based luting cement (Rely-X ARC). Bonding specimens were placed in deionized water at 37°C and stored for 24 h. The other groups were subjected to 30,000 cycles of a thermal stress for the durability test. Shear bond tests were done using a universal testing machine at 1 mm/min. Shear bond strengths of combination treatments using EP and AZ on TBC treatment after thermal stress showed no significant difference (p>0.05) compared with those of storage after 24 h. Combination treatment using phosphoric acid ester monomer could achieve a durable bond.

Aim:The purpose of this review is to address the smear layer removing the ability of root different canal irrigants including ethylenediaminetetraacetic acid (EDTA), a mixture of tetracycline, acid and detergent (MTAD), tetraclean, citric acid, Q-Mix, maleic acid, and smear clear.Background: Smear layer is a layer which is produced during instrumentation. It contains both organic and inorganic materials. It may also contain bacteria and their byproduct considering the root canal situation. This layer may prevent the penetration of the healing material introduced to the canal to the interior of the dentinal tubules. In addition, it can affect the adaptation of sealing materials to the root canal walls. Review results:The smear layer removal ability of MTAD is superior and faster than EDTA. Tetraclean is similarly composed of an acid, an antibiotic, and a detergent. The presence of doxycycline is believed to help the smear layer removal ability of these irrigants. Antibiotics such as tetracycline had similar smear layer removal ability as even citric acid. EDTA is an amino acid with a chelating ability that sequestrates metal ions. Some believed EDTA smear layer removing ability is better than MTAD, tetraclean, SmearClear, and 20% citric acid which is controversial in case of comparison between MTAD and EDTA. Phosphoric acid is efficient enough to be comparable to EDTA in removing the smear layer. Maleic acid is an organic compound with acid etching smear layer removal. Its ability seems to be similar or even better than EDTA. Citric acid as another organic acid is believed to be used as smear removing agent. HEBP is another chelating agent that can be used in combination with NaOCl; however, HEBP is a weak decalcifying agent compared to EDTA and hence cannot be applied as a mere final rinse. QMiX is a combination of CHX, EDTA, and detergent and should be used at final rinse. It is believed that QMiX is as efficient as EDTA. Smear clear is a 17% EDTA solution including an anionic and cationic (cetrimide) surfactant. The ability of QMiX is similar to EDTA. Conclusion:There are different canal irrigation solutions with various smear layer removal ability that some should be used as a mere final rinse and some should not. Clinical significance:The usage of canal irrigation solutions depends on the clinical situation and preference of the dentists. This study provides a good guide for clinician of the field.

Abstract-Hypolipidemic effects of the usual r-oryzanol (r-OZ) and a new r-OZ (N-r-OZ) with a different sterol composition from r-OZ were investigated on the hyperlipidemia induced by ingestion of a high cholesterol diet (HCD) containing 1 % cholesterol for 12 days in male Sprague-Dawley rats. Treatment with r-OZ for 6 days significantly inhibited the increase in serum total cholesterol (TC) and phospholipids (PL) induced by HCD, while the treatment with r-OZ for 12 days did not inhibit the increase of TC and PL. Treatment with N-7--OZ at 100 or 1000 mg/kg for 6 days slightly inhibited the increase of TC by HCD. The decrease of TC in high density lipoprotein (HDL-TC) was markedly inhibited by treatment with N-r-OZ for 12 days, but N-r-OZ for 6 days and r-OZ for 6 and 12 days did not inhibit the decrease of HDL-TC. Treatment with N-r-OZ for 12 days significantly inhibited the increase of PL and free cholesterol (FC) by HCD. r-OZ at 1000 mg/kg for 12 days also inhibited the increase of FC. N-r-OZ significantly reduced the atherogenic index using TC and HDL-TC by affecting the HDL-TC increase. r-OZ at 100 mg/kg and N-r-OZ at 100 mg/kg for 6 days reduced the atherogenic index using TC and HDL-TC by the inhibition of TC increase. The atherogenic index using PL and HDL-PL was only reduced by the treatment with N-r-OZ at 1000 mg/g for 12 days. The increase of triglyceride (TG) by HCD was inhibited by the treatment of N-r-OZ for 6 days (all doses) and 12 days (500, 1000 mg/kg), and y-OZ at 500 mg/kg for 6 and 12 days also inhibited the increase of TG by HCD. r-OZ and N-r-OZ had no effects on liver lipid contents. The hypolipidemic effect of N-r-OZ was slightly more potent than that of r-OZ. The inhibition of decrease in HDL-TC and increase in FC by HCD in the treatment with N-r-OZ was more potent than that of r-OZ, and these effects of N-r-OZ may be related to the accel eration of HDL function in the serum. r-Oryzanol (r-OZ) is used in the treat ments of menopausal disorders and auto nomic nerve imbalance and for the removal of stress (1, 2). The hypolipidemic effect of r OZ has been studied experimentally and clinically (3-7). Kuzuya et al. (3) has reported that r-OZ inhibits an increase of total cholesterol (TC) and a formation of serum lipid peroxide induced by the feeding of a 0.1% cholesterol diet to rats. In the exami nation of lipid metabolism in high cholesterol diet (1% cholesterol in normal chow diet containing 0, 0.5 and 2% r-OZ) -fed rats, r OZ showed an increase of TC in high density lipoprotein (HDL-TC), and it inhibited increases of esterified cholesterol (EC) and triglyceride (TG) in serum, TC in liver and acyl Co A cholesterol acyl transferase activity

Abstract-The effect of essential oils, eugenol, thymol and menthol, on ery throcytes, hepatocytes, dipalmitoyl phosphatidylcholine (DPPC)-liposomes and surface tension were studied at various concentrations.Maximal inhibition of eugenol, thymol and menthol on the hypotonic hemolysis in rat erythrocytes were observed at a concentration of 2 mM, 1 mM and 1 mM, respectively. Eugenol at 4 mM and thymol at 2 mM caused an acceleration of hypotonic hemolysis. In isolated rat hepatocytes, thymol caused an increase in GOT leakage, but eugenol at 4 mM and menthol at 0.1 and 0.4 mM inhibited the GOT leakage. The leakage of GPT from hepatocytes was inhibited by eugenol at 0.1 mM and 0.4 to 4 mM and menthol at 0.1 to 0.6 mM. The inhibition of eugenol and menthol on the LDH leakage in hepatocytes were observed at a concentration of 0.001 to 4 mM and 0.1, 0.4 and 0.6 mM, respectively. Thymol caused no change in GPT and LDH leakage. Eugenol, thymol and menthol indicated a depression of surface tension at a con centration of 0.1 mM. The rank by order of surface activity was eugenol>thymol. Eugenol, thymol and menthol depressed the phase-transition temperature of DPPC liposomes. The depression of phase-transition temperature by thymol was greater than that by eugenol and menthol. These results suggest the periapical tissue damage produced by essential oils may be related to membrane lysis and surface activity and that the their tissue penetration may be related to membrane affinity and lipid solubility.

The purposes of this study were to examine whether 2-HEMA, GM, and methacrylic acid cause contact dermatitis, and to determine the optimum concentrations of these primers for sensitization and challenge in guinea pigs. A sensitizing concentration of 0.2% 2-HEMA resulted in strong rubefaction and several vesiculopapules in response to the challenge, and a sensitizing concentration of 0.5% GM produced strong rubefaction at 24 hours. We also observed the development of contact dermatitis on human brachia in a closed-patch test. Skin that was treated with both 2-HEMA and GM clearly showed the onset of rubefaction and itchiness. 2-HEMA caused sensitized delayed allergic reactions at all the concentrations tested.

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