Effect of Citric Acid and Ethylenediaminetetraacetic Acid on the Surface Morphology of Young and Old Root Dentin

Introduction: The aim of this in vitro study was to evaluate the effect of 10% citric acid and 17% ethylenediaminetetraacetic acid (EDTA) irrigating solutions on the surface morphology of young and old root dentin by determining the number and diameter of dentinal tubules using scanning electron microscopy (SEM). Methods and Materials: Fifty healthy human teeth collected from young (≤30 years) and old (≥60 years) individuals (n=25) were first prepared with a Largo bur #2 to produce smear layer on the root canal surface. Subsequently, the crowns and the root middle and apical thirds were sectioned and removed, and the cervical thirds were sectioned vertically in the buccal-lingual direction into two equal halves. The obtained samples were then immersed in 2.5% sodium hypochlorite for 30 min and randomly separated into two treatment groups for each age group. In each age group, ten samples were selected as controls and did not receive any type of treatment. The rest of the specimens were then rinsed, dried and treated for 4 min with 10% citric acid or 17% EDTA. The samples were then assessed with SEM regarding the number and diameter of dentinal tubules. All data were assessed using Student’s t-test. The level of significance was set at 0.05. Results: Regardless of the type of treatment, no significant differences were observed in the number of open tubules between the young and old root dentin (P>0.05). Nonetheless, the diameter of the tubules in the old root dentin was larger when 17% EDTA was used (P<0.05). Both, young and old root dentin did not differ with the 10% citric acid treatment (P>0.05). Conclusion: The results showed that 17% EDTA treatment induced a significant demineralization in old root dentin.Keywords: Citric Acid; Dentinal Tubule; Ethylenediaminetetraacetic Acid; Scanning Electron Microscopy; Surface Morpholog

Comparison of primary human gingival fibroblasts from an older and a young donor on the evaluation of cytotoxicity of denture adhesives

Denture adhesives (DA) improve the retention and stability of ill-fitting dentures, especially for older adults. These materials should be biocompatible, i.e., they cannot cause undesired biological responses and be non-cytotoxic to oral tissues. However, in vitro testing of DA biocompatibility employing primary cell culture may possibly be affected by other factors, such as the donor age. Objective To compare the cytotoxicity of three different denture adhesives when assessed in primary gingival fibroblasts from a young donor or from an older donor, as well as the release of the basic fibroblast growth factor (bFGF), and the inflammatory response marker interleukin-6 (IL-6). Material and Methods Gingival fibroblasts isolated from a 30- and a 62-year-old donor were assayed for proliferation (1-7 days) and sensitivity to latex (positive control). Fibroblasts were indirectly exposed to Corega Ultra (cream), Corega powder and Fixodent Original for a 24 h period and assayed by XTT and Crystal Violet tests. The release of IL-6 and bFGF by exposed cells was determined by ELISA. Results While cells from the young donor presented higher cell growth after 7 days, the sensitivity to increasing concentrations of latex extracts was very similar between young and older cells. Both XTT and CVDE detected no difference between the DA and the control group. All materials induced higher levels of IL-6 and bFGF compared to control. Cells from the older donor exposed to Corega Ultra released lower levels of cytokine and growth factor. Conclusions All materials were considered non-cytotoxic, but affected cytokine and growth factor release. The biological differences found between fibroblasts from both donors could be due to individual or age-related factors. The authors suggest the use of cells from older donors on studies of dental products aimed at older patients, to better simulate their physiological response

Ressonância nuclear magnética: quando podemos indicar?

Objetivo: realizar uma revisão da literatura sobre os avanços, vantagens, desvantagens, indicações e contraindicações do uso da RMN em Odontologia nos dias atuais. Revisão de Literatura: o crescimento e refinamento das técnicas de RNM lhe atribuiu maior visibilidade quanto ao diagnóstico da articulação temporomandibular (ATM), sendo esta a sua principal indicação, já que permite fácil visualização do côndilo, fossa glenóide, eminência articular, disco e estruturas peridiscais. Em critério de comparação, a RNM tem sido destacada por diversos autores com superioridade sobre os demais métodos de diagnóstico, apesar de apresentar limitações quanto à definição de anormalidades ósseas, que a tomografia computadorizada realiza com maior especificidade. Conclusão: quando for necessária uma avaliação criteriosa dos tecidos moles da ATM, esse exame se demonstra um facilitador, todavia o profissional deve ser calibrado para realizar uma leitura adequada do exame

Evaluation of marginal gaps in composite resin restorations with some variation of clinical determinants

O objetivo deste estudo foi comparar, por meio de mensuração das fendas na interface dentina - restauração de resina composta com utilização de algumas variáveis: fotoativação com lâmpada halógena e com LED; utilização de resina microhíbrida com partículas nanométricas Filtek Z350 ou sem estas partículas Filtek Z250; variação do sistema adesivo (Adper Single Bond 2 ou Adper Scotchbond Multi Purpose); variação da temperatura da resina composta; uso de dessensibilizante dentinário ou não; remoção do colágeno da dentina ou não e variação da intensidade de luz na fotoativação. Foram utilizados 70 molares humanos recém-extraídos, com cavidades circulares na dentina superficial de cada face proximal, foram divididos em 10 amostras para cada variável citada acima. Os dentes foram devidamente restaurados, seguindo as instruções dos fabricantes, para todos os grupos e mantidos em estufa bacteriológica por um período de 7 dias, após este período, foram polidos e as réplicas de resina epoxídica foram confeccionadas a partir de uma moldagem com silicone por adição, as mesmas foram levadas ao MEV, para a análise. As fendas foram mensuradas com o auxílio do software UTHSCSA Image tool e os dados foram submetidos à análise estatística pelo teste t de Student para a obtenção dos resultados. Com base nos resultados obtidos pode-se concluir que: os menores valores de fendas marginais foram obtidos quando da utilização de luz halógena (t=3,246 e p= 0,02) e com variação da intensidade desta luz (t= - 8,808 e p= 0,00). Os menores valores relativos de fendas, mas sem diferença estatística significante, foram encontrados, também, quando a resina Filtek Z350 foi comparada com a resina Filtek Z250 (t=-0,426 e p= 0,672) e quando o adesivo Adper Scotchbond Multi Purpose foi comparado com o Sistema Adper Single Bond 2 (t= 0,883 e p= 0,382). Os maiores valores de fendas marginais foram obtidos com a resina Filtek Z350 préaquecida a 60oC (t= -3,961 e p=0,000); com o uso de dessensibilizante dentinário (t=-3,062 e p=0,004) e com a remoção do colágeno pelo hipoclorito de sódio (t= -8,808 e p= 0,000).The objective of this study was to compare through the cracks measurements in the dentin resin interface, using some variables: light activation with halogenic lamp and with LED; the use of micro-hybrid resin with or without nanofiller (Filtek Z350 anda Filtek Z250); variation of the adhesive systems (Adper Single Bond 2 or Scotchbond Multi Purpose); variation of the temperature in the compound resin; to use or not use the dentin desensitizing; to remove or not the dentin collagen and the light intensity variation in the light-curing. It was used 70 human extracted molars, with circular cavities in the superficial dentin of each proximal face; they were divided in 10 samples to each supra cited variable. The teeth were restored, followint the manufacturer instructions, and they were kept in a bacteriologtical kiln during a seven days period. After this time, the teeth were glossed, the resin replica were made from an addition silicone casting and these were took to the MEV, to be analyzed. The cracks were measured with the help of a UTHSCSA tool image software and the data were submited to an statistical analysis with the Student t test. The results obtained give the following conclusions: the lower values of marginal cracks were obtained when it was used the halogenic light (t = 3,246 and p = 0,02) and due the intensity variation of this light (t = 8,808 and p = 0,00). The lowest values related to the cracks were found when the Filtek Z350 resin was compared to the Filtek Z250 resin (t = 0,426 and p = 0,672), and when the Adper Scotchbond Multipurpose adhesive was compared with the Adper Single Bond 2 system (t = 0,883 and p = 0,382). The greatest values of marginal cracks were obtained with Filtek Z350 resin preheated at 60 degrees (t = -3,961 and p = 0,00); with the use of dentin desensitizing (t = -3,062 and p = 0,004) and with the removal of the collagen by using sodium hypochlorite (t = -8,808 and p = 0,000)

A study of the Masagana 99 credit delivery system in the Philippines

Typescript (photocopy).Digitized by Kansas Correctional Industrie

Recuerdos de Guatemala

Santiaguito -- Min. 03.12: Chichacastenango -- Min. 05.54: Luna de Xelaju -- Min. 08.53: Cuando llora el indito -- Min. 11.26: Ferrocarril de los Altos -- Min. 14.28: Aura marina -- Min. 17.20: Una caricia para tí -- Min. 20.08: Ishtia TerpanecaIntérpretes: Marimba Gallit

Título: Ishtia Terpaneca

Intérpretes: Marimba GallitoSantiaguito -- Min. 03.12: Chichacastenango -- Min. 05.54: Luna de Xelaju -- Min. 08.53: Cuando llora el indito -- Min. 11.26: Ferrocarril de los Altos -- Min. 14.28: Aura marina -- Min. 17.20: Una caricia para tí -- Min. 20.08: Ishtia Terpanec

Bond Strength Evaluation of Two Adhesive Systems in Fiberglass Posts Cementation

Objective: To compare the bond strength of three-step and self-etch adhesive systems with and without prior acid etching on bonding of fiberglass posts in root canals. Material and Methods: Experiments were conducted on roots of five upper molars without curvature and sectioned in a cervical-apical direction. With the aid of a high-speed turbine and diamond tips, cylindrical cavities 7 mm in depth and 1.4 mm in diameter were made in the dentine. The roots of the same tooth were used, where the retainers were cemented, thus generating three groups: Group A: Adper Scotchbond Multipurpose Plus (SBMP) + Rely X ARC; Group B: Single Bond Universal (SBU-1) + Rely X ARC, with acid etching prior to adhesive insertion; Group C: Single Bond Universal (SBU-2) + Rely X ARC. The samples were stored in a bacteriological incubator at 37ºC with 100% humidity for 48h and were subsequently cross-sectioned to obtain 3 dentine discs 1mm in thickness. Forty-five specimens were subjected to the push-out test. Results: Through the analysis of variance and Tukey's test, it was found that SBMP showed, with statistical significance (p<0.05), highest bond strength when compared with the SBU-1 and SBU-2 systems. The observed difference in the discs was located in the cervical portion. Conclusion: The three-step adhesive system had higher bond strength with the substrate than the self-etching adhesive only in the disc in the cervical portion; further, statistically, the prior application of phosphoric acid in SBU-1 did not affect its bond strength significantly

The lived experiences of registered nurses working in other fields of practice

This study focused on recognizing and understanding the lived experiences of registered nurses who are working in other fields of practice not related to nursing. Qualitative research was used. A total of seven (7) respondents were chosen using purposive sampling. Data was collected using scheduled interviews. The themes of the study were situated in the context of a journe from the river towards the sea to reach a destination. The journey entails different experiences, good and bad, before the nurses finally landed a destination of their choice. The study highlighted and uncovered the many wonders and surprises entailed in the stories of the various registered nurses working in other fields of practice. It emphasized in the study that every individual’s experience differ from one another. Amidst these differences was a common beginning: the nursing profession has given them remarkable experiences, both good and bad, that made them grow as a better person