Evaluation of degree of conversion and hardness of dental composites photo-activated with different light guide tips

Objective: The aim of this study was to evaluate the degree of conversion and hardness of different composite resins, photo-activated for 40 s with two different light guide tips, fiber optic and polymer. Methods: Five specimens were made for each group evaluated. The percentage of unreacted carbon double bonds (% C═C) was determined from the ratio of absorbance intensities of aliphatic C═C (peak at 1637 cm−1) against internal standard before and after curing of the specimen: aromatic C-C (peak at 1610 cm−1). The Vickers hardness measurements were performed in a universal testing machine. A 50 gf load was used and the indenter with a dwell time of 30 seconds. The degree of conversion and hardness mean values were analyzed separately by ANOVA and Tukey’s test, with a significance level set at 5%. Results: The mean values of degree of conversion for the polymer and fiber optic light guide tip were statistically different (P<.001). The hardness mean values were statistically different among the light guide tips (P<.001), but also there was difference between top and bottom surfaces (P<.001). Conclusions: The results showed that the resins photo-activated with the fiber optic light guide tip promoted higher values for degree of conversion and hardness.

Estudo da expressão imuno-histoquímica das proteínas MMP-9, MMP-13 e TIMP-1 em ameloblastomas e tumores odontogênicos ceratocistos

Ameloblastomas and keratocystic odontogenic tumors (KOT) represent odontogenic lesions that, despite their benign nature, are distinguished by a distinct biological behavior, characterized by locally aggressive growth and recurrent episodes. The gnathic bone resorption caused by the growth of these lesions is a key to the expansion of the same, both being mediated by osteoclastic cells like enzymatic activity of various matrix metalloproteinases (MMPs) factor. The expression of stimulatory factors and inhibitors of bone resorption has been correlated with the development of these lesions, with emphasis to some MMPs such as collagenases and gelatinases and tissue inhibitors of metalloproteinases (TIMPs), among others. Based on the premise that stimulatory and inhibitory factors of osteolytic processes can be decisive for the growth rate of intraosseous odontogenic lesions, this experiment evaluated the immunoreactivity of MMP-9, -13 and TIMP-1 protein in the epithelium and mesenchyme of ameloblastoma and the KOT specimens, by a quantitative analysis of the immunoreactivity cells. Statistical analysis was performed using the Mann-Whitney and Wilcoxon tests with a significance level set at 5 %. Immunohistochemical expression of MMP-9, -13 and TIMP-1 was observed in 100% of cases both in the epithelium and in mesenchyme. The immunoreactivity in the epithelium of KOT and ameloblastomas revealed a predominance of score 3 for MMP-9 (p=0.382) and MMP-13 (p=0.069) and no statistically significance for TIMP-1, the latter being significantly higher immunoreactivity in ameloblastomas. In the mesenchyme, there was a higher score immunoreactivity of MMP-13 (p=0.031) in ameloblastomas in relation to KOT, whereas for MMP-9 and TIMP-1 no statistically significant difference (p=0.403 was observed, p=1.000). The calculation of the ratio of scores revealed expression of proteins in general, similarity of the lesions, a significant predominance of equal expression of TIMP-1 and MMP-9 was observed only in the epithelium of ameloblastoma. The marked immunostaining of MMP-9 , MMP-13 and TIMP-1 in epithelium and mesenchyme of the lesion indicate that these proteins involved in ECM remodeling required for tumor progression, however, specific differences in the expression of some of these proteins, are not sufficient to suggest differences in the biological behavior of ameloblastomas and KOTs

On fuzzy ideals and fuzzy filters of fuzzy lattices

In the literature there are several proposals of fuzzi cation of lattices and ideals concepts. Chon in (Korean J. Math 17 (2009), No. 4, 361-374), using the notion of fuzzy order relation de ned by Zadeh, introduced a new notion of fuzzy lattice and studied the level sets of fuzzy lattices, but did not de ne a notion of fuzzy ideals for this type of fuzzy lattice. In this thesis, using the fuzzy lattices de ned by Chon, we de ne fuzzy homomorphism between fuzzy lattices, the operations of product, collapsed sum, lifting, opposite, interval and intuitionistic on bounded fuzzy lattices. They are conceived as extensions of their analogous operations on the classical theory by using this de nition of fuzzy lattices and introduce new results from these operators. In addition, we de ne ideals and lters of fuzzy lattices and concepts in the same way as in their characterization in terms of level and support sets. One of the results found here is the connection among ideals, supports and level sets. The reader will also nd the de nition of some kinds of ideals and lters as well as some results with respect to the intersection among their families. Moreover, we introduce a new notion of fuzzy ideals and fuzzy lters for fuzzy lattices de ned by Chon. We de ne types of fuzzy ideals and fuzzy lters that generalize usual types of ideals and lters of lattices, such as principal ideals, proper ideals, prime ideals and maximal ideals. The main idea is verifying that analogous properties in the classical theory on lattices are maintained in this new theory of fuzzy ideals. We also de ne, a fuzzy homomorphism h from fuzzy lattices L and M and prove some results involving fuzzy homomorphism and fuzzy ideals as if h is a fuzzy monomorphism and the fuzzy image of a fuzzy set ~h(I) is a fuzzy ideal, then I is a fuzzy ideal. Similarly, we prove for proper, prime and maximal fuzzy ideals. Finally, we prove that h is a fuzzy homomorphism from fuzzy lattices L into M if the inverse image of all principal fuzzy ideals of M is a fuzzy ideal of L. Lastly, we introduce the notion of -ideals and - lters of fuzzy lattices and characterize it by using its support and its level set. Moreover, we prove some similar properties in the classical theory of - ideals and - lters, such as, the class of -ideals and - lters are closed under intersection. We also de ne fuzzy -ideals of fuzzy lattices, some properties analogous to the classical theory are also proved and characterize a fuzzy -ideal on operation of product between bounded fuzzy lattices L and M and prove some results.

Expressão imuno-histoquímica das proteínas E-Caderina e BCL2 e nevos melanociticos orais e cutâneos

Melanocytic nevi (MNs) are benign melanocytic proliferations of cells, which can be found in the skin and mucous coat, including the oral mucosa. However, skin NMs are more common when compared to those that affect the oral mucosa. The molecular mechanisms involved in the development of nevi and the factors that can influence the migration pattern of the nevus cells are little explored. The aim of this study was to analyze the immunohistochemical expression of E-cadherin protein and Bcl-2 in oral / skin NMs and relate them to the clinical characteristics (gender, age, location, exposure to solar radiation) and histopathological types. 36 cases of oral NMs and 34 Skin NMs were analyzed. The immunohistochemistry was used of the protein E-cadherin and bcl-2, which were analyzed the intensity (weak, moderate and strong) and distribution marking (diffuse and focal). The immunoreactivity also analyzed as to the types of nevus cells (epithelioid cells -A, -B lymphocyte and fibroblast-like -C). Statistical analysis was performed using the chi-square tests of Pearson and Spearman correlation with significance level set at 5%. Of the 70 cases of NMs, 82.9% were female, 48.6% aged 26-50 years, 51.4% were diagnosed histologically as intradermal / intramucosal nevi and 80% were NMs acquired. Immunohistochemical expression of BCL2 and E-cadherin were variables in the sample and showed no association with clinical parameters. The expression of bcl-2 and E-cadherin were variable according to the types of nevus cells (A, B and C) (P = 0.001). The expression of bcl-2 was more diffuse in congenital MNs (p = 0.002). E-cadherin was positive in 83.3% of MNs <1cm (p = 0.001) and exhibited weak staining in 73.9% of MNs that were in exposed areas (p = 0.010). Based on these results, it is suggested that the E-cadherin has a modulating effect on the migratory properties of NMs, and bcl-2 is a marker of MNs with increased proliferative capacity.