Joensenstark7170

Abundant hydration, diffusivity, and volatile phase composition render the surface of calcium phosphates (CPs) a complex dynamic region. Three CP powders were analyzed using X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS) with regard to their surface compositions and fine structures hydroxyapatite (HAp), amorphous CP (ACP), and a CP formed under the same conditions as ACP but allowed to ripen into HAp (ACP → HAp). XPS analyses revealed that the Ca/P atomic ratio in the 2-10 nm-thick layers of the nanoparticle surface was somewhat lower than the stoichiometric ratio for all the three CPs. However, it was still lower for ACP and ACP → HAp than that for HAp, indicating the incongruent dissolution of all the surfaces and also greater instability and higher solubility of ACP and ACP → HAp as compared to those of HAp. ARS-1620 Consequently, as indicated by both XPS and ISS, the amount of adventitious carbon bound to HAp was higher than that on ACP or ACP → HAp. The binding energies of the most ien the surfaces of the two different forms of HAp as compared to that for ACP, but also a definite impression of the traces of their formation history on them.Induction of premalignant lesions in animal models is of high value for research purposes. This study aimed to induce dysplasia in hamster mucosal pouch for investigation of dysplastic lesions using dimethylbenz(a)anthracene. The buccal pouch of 10 hamsters was painted with dimethylbenz(a)anthracene for 10 weeks every other day. At 5 and 10 weeks, they underwent histopathological analysis. Clinically, there was no change until week 7; after which mucosal thickening occurred. Hamsters scarified at 5 weeks and 10 weeks demonstrated mild and moderate dysplasia, respectively. dimethylbenz(a)anthracene is a useful tool for inducing dysplastic lesions in the buccal pouch mucosa of hamsters. Copyright© Dental Research Center, Tehran University of Medical Sciences.Objectives Color change of cements over time can be detected through translucent ceramic veneers, compromising the aesthetic appearance of restorations in the long-term. This study aimed to assess the color stability of ceramic laminate veneers cemented with self-adhesive resin cements after accelerated aging. Materials and Methods In this study, 21 IPS e.max ceramic discs, measuring 8mm in diameter and 0.7 mm in thickness, were fabricated and divided into three groups (n=7) for the application of Choice 2 total-etch light-cure resin cement, RelyX U200 dual-cure self-adhesive resin cement, and SpeedCEM self-cure self-adhesive resin cement. The ceramic discs in each group were cemented on the prepared facial surface of bovine teeth. The color parameters were assessed using a spectrophotometer. Subsequently, the samples were subjected to accelerated aging for 100 hours, and the color parameters were measured again. The data were analyzed using two-way repeated-measures analysis of variance (ANOVA) and Tamhane's post-hoc test (P3.5). The color change of the other two groups was clinically acceptable (1 less then ΔE less then 3.5). Conclusion The self-adhesive dual-cure cement showed color stability comparable to that of the total-etch light-cure cement for cementation of IPS e.max ceramic laminates. The color stability of both cements was superior to that of the self-adhesive self-cure cement. Copyright© Dental Research Center, Tehran University of Medical Sciences.Objectives Considering the emergence of resistant microbes and side effects of chemical drugs, in this study, the inhibitory effect of organic and hydro-alcoholic extracts of Boswellia serrata (B. serrata) on some oral microbiota was investigated. Materials and Methods In this experimental study, standard strains of Candida albicans (C. albicans; PTCC 5027), Candida glabrata (C. glabrata; PTCC 5295), Candida krusei (C. krusei; PTCC 5297), and Streptococcus mutans (S. mutans; PTCC 1688) were collected from the Iranian Research Organization for Science and Technology (IROST). Then, the minimum inhibitory concentration (MIC) of organic and hydro-alcoholic extracts of B. serrata was determined based on the CLSI protocol and using the micro-dilution method. The contents of each well were subcultured in Müller-Hinton agar (Candida species) and blood agar (S. mutans). The lowest concentration with no growth was considered as the minimum fungicidal concentration (MFC) or bactericidal concentration (MBC). Statistical analyses were performed using Mann-Whitney test. Results Hydro-alcoholic extract of B. serrata at the concentration of 50 mg/ml inhibited the growth of C. albicans and S. mutans. It also inhibited the growth of C. krusei and C. glabrata at the concentration of 100 mg/ml. Organic extract of B. serrata at the concentration of 200 mg/ml only inhibited the growth of C. glabrata. Conclusion Hydro-alcoholic extract of B. serrata had a greater inhibitory effect on C. albicans and S. mutans compared to the organic extract. Copyright© Dental Research Center, Tehran University of Medical Sciences.Objectives We aimed to evaluate the knowledge and attitude of Iranian dentists towards cone-beam computed tomography (CBCT). Materials and Methods A 20-item questionnaire was distributed among 410 Iranian dentistry graduates attending the 56th Congress of Iranian Dental Association held in Tehran, Iran. The questionnaire included items on demographic characteristics, namely full name, age, gender, work experience, type of current activity (individual or group), and the highest educational level. In addition, the questionnaire contained items on the knowledge and attitude of dentists. The obtained data were analyzed using statistical tests. Results In this study, 49.3% and 22.4% of the subjects were male and female, respectively, 47.1% of whom used CBCT, while 49.8% did not. In detail, 72.2% of the dentists used the technique to evaluate the location of implants, whereas 19.7%, 3.2%, and 2.7% of the subjects applied it to localize the inferior alveolar nerve (IAN), evaluate the location of implants and localize the IAN, and perform cephalometric analysis, respectively. The main causes of lack of prescription of CBCT entailed high cost (80%), high rate of patient absorbed dose (27.6%), insufficient number of CBCT centers (46.3%), and the long duration of the process (15.6%). Conclusion CBCT is an advantageous imaging technique in dentistry. Considering the increased application of CBCT in dentistry, attending workshops could help train dentists to use the technique. Copyright© Dental Research Center, Tehran University of Medical Sciences.