ABSTRACT
OBJECTIVES: The aim of this study was to determine the effect of epigallocatechin gallate (EGCG) on the shear bond strength of composite resin to bleached enamel. MATERIALS AND METHODS: Ninety enamel surfaces of maxillary incisors were randomly divided into 9 groups as follows: G1: control (no bleaching); G2: bleaching; G3: bleaching and storage for seven days; G4 - 6: bleaching and application of 600, 800 and 1,000 micromol of EGCG-containing solution for 10 minutes, respectively; G7 - 9: bleaching and application of 600, 800 and 1,000 micromol of EGCG-containing solution for 20 minutes, respectively. The specimens were bleached with 30% hydrogen peroxide gel and a composite resin cylinder was bonded on each specimen using a bonding agent. Shear bond strength of the samples were measured in MPa. Data was analyzed using the two-way ANOVA and Tukey HSD tests (alpha = 0.05). RESULTS: The maximum and minimum mean shear bond strength values were observed in G1 and G2, respectively. Time and concentration of EGCG showed no significant effects on bond strength of the groups (p > 0.05). Multiple comparison of groups did not reveal any significant differences between the groups except for G2 and all the other groups (p < 0.05). CONCLUSIONS: There is a significant decrease in bond strength of composite resin to enamel immediately after bleaching. A delay of one week before bonding and the use of EGCG increased bond strength of composite resin to bleached enamel.
Subject(s)
Catechin , Dental Enamel , Hydrogen Peroxide , Incisor , Tooth BleachingABSTRACT
Hepatitis includes a wide range of clinical and pathological conditions. The beta-2 microglobulin [B[2][M], as part of the HLA complex, is responsible for transmission of viral antigens on the surface of liver cells. The purpose of this study is to determine the concentration of salivary B2M as a marker of viral proliferation in subjects who are HbsAg[1], HBV DNA PCR[+] compared with those who are HbsAg[+], HBV DNA PCR[-]. In this case-control study, we enrolled 25 patients who were Hbs Ag[+], HBV DNA PCR[+] in addition to 21 patients who were Hbs Ag[+], HBV DNA PCR[-]. We obtained sputum samples from all patients and measured salivary B[2]M levels by nephelometry. Data analyses were performed by the descriptive, student's t- and chi-square tests. There were 25 men [54.3%] and 21 women [45.7%] with a mean age of 35.72 +/- 11.86 years who participated. Of PCR[+] patients, 72% were on medication, however 85.7% of the PCR[-] patients did not take medication [p<0.001]. Salivary B[2]M concentration in the PCR[+] patients [5.28 +/- 5.45] was greater than observed in the PCR patients [1.51 +/- 0.77], of which this difference was statistically significant [p<0.003]. Salivary B2M levels, as a marker of viral replication, could be used in patients with hepatitis B