1.
Effect of bleaching protocols with 38% hydrogen peroxide and post-bleaching times on dentin bond strength.
Souza-Gabriel, AE, Vitussi, LO, Milani, C, Alfredo, E, Messias, DC, Silva-Sousa, YT
Brazilian dental journal. 2011;(4):317-21
Abstract
This study assessed the effect of bleaching protocols with 38% hydrogen peroxide (HP) and post-bleaching times on shear bond strength of a composite resin to dentin. One-hundred slabs of intracoronary dentin were included and randomly assigned into 2 groups according to the bleaching protocol: HP (2 applications of 10 min each) and HP activated by LED laser (2 applications of 10 min each/45 s of light activation). Groups were subdivided according to the post-bleaching time (n=10): 1 day, 3 days, 7 days, 10 days and 14 days. The control group was unbleached and restored (n=10). The specimens were restored with Single Bond adhesive system/Filtek Z250 resin using a polytetrafluorethylene matrix and were submitted to the shear bond strength testa after 24 h,. Data were analyzed by ANOVA and Tukey's test (α=0.05). Unbleached group (0.283 ± 0.134) had the highest bond strength and was statistically similar (p>0.05) to HP/10 days (0.278 ± 0.064), HP + LED laser/10 days (0.280 ± 0.078), HP/14 days (0.281 ± 0.104), HP + LED laser/14 days (0.277 ± 0.093). Lower bond strength were verified in HP/1 day (0.082 ± 0.012), HP/3 days (0.079 ± 0.013), HP + LED laser/1 day (0.073 ± 0.018) and HP + LED laser/3 days (0.080 ± 0.015), which were statistically similar (p>0.05). HP/7 days (0.184 ± 0.154) and HP + LED laser/7 days (0.169 ± 0.102) had intermediate values (p<0.05). The restorative procedure of intracoronary dentin bleached with 38% HP with or without the use of light source should be performed after at least 10 days after the bleaching treatment.
2.
Inflammation and oxidant-stress in beta-thalassemia patients treated with iron chelators deferasirox (ICL670) or deferoxamine: an ancillary study of the Novartis CICL670A0107 trial.
Walter, PB, Macklin, EA, Porter, J, Evans, P, Kwiatkowski, JL, Neufeld, EJ, Coates, T, Giardina, PJ, Vichinsky, E, Olivieri, N, et al
Haematologica. 2008;(6):817-25
Abstract
BACKGROUND We assessed whether oxidant-stress and inflammation in beta-thalassemia could be controlled by the novel oral iron chelator deferasirox as effectively as by deferoxamine. DESIGN AND METHODS Forty-nine subjects were enrolled from seven sites and studied at baseline, and after 1, 6, and 12 months of therapy. Malondialdehyde, protein carbonyls, vitamins E and C, total non-transferrin bound iron, transferrin saturation, C-reactive protein, cytokines, serum ferritin concentration and liver iron concentration were measured. RESULTS Liver iron concentration and ferritin declined significantly in both treatment groups during the study. This paralleled a significant decline in the oxidative-stress marker malondialdehyde (deferasirox -22%/year, deferoxamine -28%/year, average decline p=0.006). The rates of decline did not differ between treatment groups. Malondialdehyde was higher in both treatment groups than in a group of 30 non-thalassemic controls (p < 0.001). The inflammatory marker high-sensitivity C-reactive protein decreased significantly only in the group receiving deferasirox (deferasirox -51%/year, deferoxamine +8.5%/year, p = 0.02). This result was confounded by a chance difference in the level of high-sensitivity C-reactive protein between the two groups at baseline, but analyses controlling for this difference suggested an equally large treatment effect. CONCLUSIONS Iron chelation therapy with deferoxamine or with deferasirox was equally effective in decreasing iron burden and malondialdehyde. The possible differential effect of the two chelators on inflammation warrants further investigation.
3.
Effects of potassium nitrate and oxalate desensitizer agents on shear bond strengths of orthodontic brackets.
Türkkahraman, H, Adanir, N
The Angle orthodontist. 2007;(6):1096-100
Abstract
OBJECTIVE To evaluate the effects of potassium nitrate and oxalate desensitizer agents on shear bond strengths of orthodontic brackets. MATERIALS AND METHODS Forty-five extracted human premolar teeth were randomly assigned to three groups of 15 each. UltraEZ potassium nitrate desensitizer was applied on teeth in the first group, while BisBlock oxalate desensitizer was applied on teeth in the second group. The third group served as a control. Orthodontic brackets were bonded with a light cure composite resin and cured with a halogen light. After bonding, the shear bond strength of the brackets was tested with a universal testing machine. RESULTS The highest shear bond strengths were measured in Group III. The shear bond strength in Groups I and II was significantly lower than in Group III (P < .001). Significant difference was also found between Group I and Group II (P < .01). CONCLUSIONS Orthodontic brackets bonded to enamel treated with potassium nitrate and oxalate desensitizers showed significantly lower bond strengths than did brackets bonded to untreated enamel.
4.
Bleaching and desensitizer application effects on shear bond strengths of orthodontic brackets.
Türkkahraman, H, Adanir, N, Güngör, AY
The Angle orthodontist. 2007;(3):489-93
Abstract
OBJECTIVE To evaluate the effects of bleaching and desensitizer application on shear bond strengths of orthodontic brackets. MATERIALS AND METHODS Forty-eight extracted human premolar teeth were randomly assigned to 4 groups of 12 each. The first group of teeth was bleached with a 35% hydrogen peroxide office bleaching agent. The second group was bleached the same as the first group and UltraEZ desensitizer was applied. No bleaching procedures were applied on the third and fourth groups. UltraEZ desensitizer alone was applied to teeth in the third group. The fourth group served as control. Orthodontic brackets were bonded with a LC (light cure) composite resin and cured with a halogen light. After bonding, the shear bond strengths of the brackets were tested with a Universal testing machine. RESULTS The results showed that bleaching, bleaching plus desensitizer, and desensitizer procedures significantly reduced the bonding strengths of the orthodontic brackets (P < .05, P < .001, and P < .01, respectively). No statistically significant difference was found between bleaching, bleaching plus desensitizer, and desensitizer groups (P > .05). CONCLUSIONS Because bleaching and desensitizer application significantly affected shear bond strengths of orthodontic brackets on human enamel, they should be delayed until the completion of orthodontic treatment.