Cementum and dentin repair following root damage caused by the insertion of self-tapping and self-drilling miniscrews.

OBJECTIVE: The aim of this study was to evaluate the histological responses of cementum, root dentin, and pulp following intentional root injuries caused via self-tapping and self-drilling miniscrews. MATERIALS AND METHODS: Fourteen patients (with a mean age of 15.7 years and age range of 14-18 years) who were scheduled for the extraction of all four first premolars as part of their orthodontic treatment plan participated in this study. The roots of the right and the left quadrants' first premolars were designedly injured using self-tapping miniscrews and self-drilling miniscrews, respectively. Teeth were extracted eight weeks after the injury. Cementum repair was assessed through histological examinations. RESULTS: In this study, 40 teeth (75.4%) showed reparative cementum formation and 13 teeth (24.5%) showed no repair. There was no significant difference between the two groups regarding the formation of reparative cementum (P = 0.3). In all examined teeth, the inflammatory response of the pulp to the cold test was within the normal range. CONCLUSION: This study showed that in most cases, the healing of cementum was observed eight weeks after the injury and the two methods of miniscrew insertion showed no significant difference when it comes to the healing process.

Microhardness of demineralized enamel following home bleaching and laser-assisted in office bleaching.

BACKGROUND: There is little data regarding the effect of tooth whitening on microhardness of white spot lesions. This study was conducted to investigate the effect of home-bleaching and laser-assisted in-office bleaching on microhardness of demineralized enamel. MATERIAL AND METHODS: Forty bovine incisors were selected and immersed in a demineralizing solution for 12 weeks to induce white spot lesions. Enamel blocks were prepared and randomly assigned to two groups of 20 each. The first group underwent home bleaching with 15% carbamide peroxide which was applied for 8 hours a day over a period of 15 days. In the second group, in-office bleaching was performed by 40% hydrogen peroxide and powered by irradiation from an 810 nm gallium-aluminum-arsenide (GaAlAs) diode laser (CW, 2W). This process was performed for 3 sessions every seven days, in 15 days. The specimens were stored in Fusayama Meyer artificial saliva during the experiment. Surface microhardness was assessed before and after the bleaching therapies in both groups. RESULTS: Microhardness decreased significantly following both home bleaching and laser-assisted in-office bleaching (p<0.05). There were no significant differences in hardness values among the two groups either before (p=0.131) or after (p=0.182) the bleaching procedures. CONCLUSIONS: Tooth whitening through home bleaching or laser-assisted in-office bleaching can result in a significant reduction in microhardness of white spot lesions. Therefore, it is suggested to take protective measures on bleached demineralized enamel. Key words:White spot lesion, bleaching, laser, microhardness, demineralized enamel, home bleaching, in-office bleaching.

The effects of wet cupping on serum high-sensitivity C-reactive protein and heat shock protein 27 antibody titers in patients with metabolic syndrome.

INTRODUCTION: It has previously been reported that increased level of serum heat shock proteins (Hsps) antibody in patients with metabolic syndrome. It is possible that the expression of Hsp and inflammatory markers can be affected by cupping and traditional Chinese medicine. There is a little data investigating the effects of cupping on markers of inflammation and Hsp proteins, hence, the objective of this study was evaluation of the effects of wet cupping on serum high-sensitivity C-reactive protein (hs-CRP) and Hsp27 antibody titers in patients with metabolic syndrome. SUBJECTS AND METHODS: Serum Hs-CRP and Hsp27 antibody titers were assessed in samples from 126 patients with metabolic syndrome (18-65 years of age) at baseline, and after 6 and 12 weeks after treatment. One hundred and twenty-six patients were randomly divided into the experimental group treated with wet cupping combined with dietary advice, and the control group treated with dietary advice alone using a random number table. Eight patients in case group and five subjects in control groups were excluded from the study. Data were analyzed using SPSS 15.0 software and a repeated measure ANCOVA. RESULTS: Serum hs-CRP titers did not change significantly between groups (p>0.05) and times (p=0.27). The same result was found for Hsp27 titers (p>0.05). CONCLUSION: Wet-cupping on the interscapular region has no effect on serum hs-CRP and Hsp27 patients with metabolic syndrome.

Simple method for reliable predicting flash points of unsaturated hydrocarbons.

This work introduces a simple method for prediction of the flash point of different classes of unsaturated hydrocarbons including alkenes, alkynes and aromatics. Elemental composition is used as a core function that can be revised for some compounds by a correcting function. The predicted flash points for a data set of 173 unsaturated hydrocarbons are in good agreement with the measured values such that the root mean square (rms) error is 9 K. The estimated flash points for 76 furthers compounds have been compared with two new group additivity methods, where these methods can be applied, that the new method gives a lower rms value. It is shown that the new model can easily be used for any unsaturated hydrocarbons with complex molecular structures.