Patrícia Aleixo dos Santos

Chemical and morphological features of dental composite resin: Influence of light curing units and immersion media

The study evaluated the influence of light curing units and immersion media on superficial morphology and chemistry of the nanofilled composite resin Supreme XT (3M) through the EDX analysis and SEM evaluation. Light curing units with different power densities and mode of application used were XL 3000 (480 mW/cm2), Jet Lite 4000 Plus (1230mW/cm2), and Ultralume Led 5 (790 mW/cm2) and immersion media were artificial saliva, Coke®, tea and coffee, totaling 12 experimental groups. Specimens (10 mm × 2 mm) were immersed in each respective solution for 5 min, three times a day, during 60 days and stored in artificial saliva at 37°C ± 1°C between immersion periods. Topography and chemical analysis was qualitative.

Influence of surface sealant on the translucency of composite resin: effect of immersion time and immersion media

This study evaluated the effect of surface sealant on the translucency of composite resin immersed in different solutions. The study involved the following materials: Charisma, Fortify and coffee, Coca-Cola®, tea and artificial saliva as solutions. Sixty-four specimens (n = 8) were manufactured and immersed in artificial saliva at 37 ± 1 °C. Samples were immersed in the solutions for three times a day and re-immersed in artificial saliva until the translucency readings. The measurements were carried out at nine times: T1 - 24 hours after specimen preparation, T2 - 24 hours after immersion in the solutions, T3 - 48 hours and T4 to T9 - 7, 14, 21, 30, 60 and 90 days, respectively, after immersion. The translucency values were measured using a JOUAN device. The results were subjected to ANOVA and Tukeys test at 5%. The surface sealant was not able to protect the composite resin against staining, the coffee showed the strongest staining action, followed by tea and regarding immersion time, a significant alteration was noted in the translucency of composite resin after 21 days.

Adhesion and proliferation of HeLa and fibroblast cells on chemically-modified gold surfaces

The development of materials that allow proper functioning of cells on solid supports is directly relevant to the construction of living-cell biosensors. Both physical and chemical properties of the surfaces have been shown to be critical in this field. Our aim is to report correlations between chemical properties of surfaces and cell behavior by studying adhesion, viability and proliferation of fibroblasts and HeLa cells. Neither fibroblasts nor HeLa cells adhered to a hydrophobic surface. Fibroblasts were able to attach and proliferate well on all other surfaces tested. In contrast, on some surfaces where HeLa cells adhered and were viable, proliferation decreased by half while on others proliferation was not affected. Proliferation was significantly correlated with the level of adsorption of serum proteins on the surface (quantified by surface plasmon resonance), but not with surface wettability (water contact angle). Interestingly, surfaces modified with COOH and HSO3 groups were the ones that favored most protein adsorption and allowed the best measures for HeLa cell proliferation. The decrease of HeLa cell proliferation on surfaces covered with poly-L-lysine (PL) was related with the profile of integrin expression. Compared to a polystyrene control surface, there was an increase in αV and αVβ3 and a decrease in α2 and α3, indicating that migration rather than proliferation could be favored on PL functionalized surfaces. These results indicate that charge is more important than wettability to determine biocompatibility.

Surface roughness and hardness of a composite resin: influence of finishing and polishing and immersion methods

Sao Paulo State Univ, Araraquara Sch Dent, Dept Childrens Dent, BR-13560450 Sao Carlos, SP, Brazil

Influence of fluoride-containing solutions on the translucency of flowable composite resins

The aim of this study was to evaluate the influence of fluoride-containing solutions on the translucency of flowable composite resins, with respect the immersion time. Flow-It! (FI) and Natural Flow (NF) composite resins and three commercial brands of fluoride-containing solutions (Fluordent, Fluorgard and Oral B) were used. Specimens were prepared and stored in the solutions at 37°C, until the measurements were made after the following treatments: T1 - after 1 hour in relative humidity; T2 - after 1 h in solution; T3 - 24 h; T4 - 48 h; T5 - after a week; from T9, the measurements were accomplished weekly, up to 30-day immersion. To obtain translucency values an electrophoresis equipment was employed. Data were submitted to ANOVA and Tukey tests. The results disclosed that NF showed highest values of translucency and was statistically different from FI (p< 0.001). As regards the solutions, Fluordent and Oral B presented similar values and were statistically superior to Fluorgard (p< 0.05). Concerning the immersion time, similar results were observed for the different evaluation periods. It may be concluded that the fluoride-containing solutions affected the translucency of the composite resins, independently of the materials used. Among the tested resins, NF presented the best performance.

Oral health educative-preventive program at school

This study has the aim of evaluation two different educational methods as: explanatory folders and lectures, at the implementation of an educative-preventive program about oral health developed at elementary public schools in Araraquara (SP) city. The sample was constituted by schoolchildren from fifth and sixth grades of four schools selected by convenience, divided in two groups: GA (n=303) that received only the folders and GB (n=245) that read the folders and also attended lectures. A questionnaire was applied before and fifteen days after program. The distribution of frequency was calculated and after that, to intergroup comparison chi-square test was used, and intragroup, the McNemar test ( α =0,05). Most of schoolchildren understand that the consumption of sugary food has to be done after main meals and they are able to associate sugar consumption with tooth decay, beyond they do not know that sugar belongs to carbohydrates group. A healthy meal was considered dependent of type of food for 52% of GA and 44% of GB before the program, and 48% and 39% fifteen days after it. Initially, only 31% of GA and 30% of GB knew the ideal moment for tooth brushing. Methods of plaque prevention seemed familiar to schoolchildren. There was a difficulty to define the features of periodontal disease. At intergroup analyses, there was statistical difference to questions 3,5,6,8 and 11, comparing two moments; at intragroup analyses, GA showed significant knowledge change only to question 4 while for GB, same occurred to questions 3,4,5,6,8 and 11, accusing more effectiveness to educational method adopted by GB. The isolated use of the folder has not increased the level of oral health information while the association of folder with lectures increased their knowledge.