Estrutura do esmalte humano e sua interface com sistemas adesivos

Esta tese sistematiza uma série de estudos dedicados à compreensão da interface do esmalte e sistemas adesivos. Para tanto, a estrutura da camada aprismática do esmalte em alta resolução pela microscopia eletrônica de varredura foi avaliada quanto a sua continuidade, espessura, distribuição nas faces coronárias e em fossas e fissuras, predominantemente em dentes decíduos não erupcionados. Foi também analisado pela microscopia eletrônica de varredura os efeitos do condicionamento de diferentes tipos de ácido e, em especial, do ácido fosfórico em diferentes concentrações, metodologias e tempos de aplicação. Estes trabalhos permitiram visualizar as principais ações ácidas desmineralizantes e os tipos de retenções no centro ou periferias dos prismas ou em ambas as regiões, bem como a profundidade e forma dos “tags” resinosos com carga e sem carga na intimidade do esmalte. No caso particular da aplicação dos selantes em fossas e fissuras foi também avaliada comparativamente a eficácia das técnicas invasivas ou não invasivas. Os últimos experimentos foram dedicados ao estudo da microinfiltração de diferentes sistemas adesivos e da resistência destes sistemas adesivos na estrutura do esmalte. Novos estudos merecem dar continuidade à linha de pesquisa de sempre priorizando o propósito de vincular os procedimentos aplicados com uma consistente e indispensável fundamentação de pesquisa básica no interesse da clínica odontopediátrica.

Efeito de dentifrícios fluoretados e suplementados com nanopartículas de trimetafosfato de sódio sobre a desmineralização, remineralização e erosão dentária

Pós-graduação em Ciência Odontólogica - FOA

Efeito de vernizes fluoretados suplementados com trimetafosfato de sódio na desmineralização e remineralização do esmalte bovino: estudos in vitro e in situ

Pós-graduação em Ciência Odontólogica - FOA

Efeito da escovação utilizando dentifrícios com diferentes graus de abrasividade no desgaste do esmalte após o uso de agentes clareadores com e sem cálcio, em diferentes intervalos de tempo

Pós-graduação em Odontologia Restauradora - ICT

Desgaste e rugosidade superficial de um cimento de ionômero de vidro nanoparticulado

To compare the abrasion wear resistance and superficial roughness of different glass ionomer cements used as restorative materials, focusing on a new nanoparticulate material. Material and Method: Three glass ionomer cements were evaluated: Ketac Molar, Ketac N100 and Vitremer (3M ESPE, St. Paul, MN, USA), as well as the Filtek Z350 (3M ESPE, St. Paul, MN, USA). For each material were fabricated circular specimens (n=12), respecting the handling mode specified by the manufacturer, which were polished with sandpaper disks of decreasing grit. The wear was determined by the amount of mass (M) lost after brushing (10,000 cycles) and the roughness (Ra) using a surface roughness tester. The difference between the Minitial and Mfinal (ΔM) as well as beroughness of aesthetic restorative materials: an in vitro comparison. SADJ. 2001; 56(7): 316-20. 11. Yip HK, Peng D, Smales RJ. Effects of APF gel on the physical structure of compomers and glass ionomer cements. Oper. Dent. 2001; 26(3): 231-8. 12. Ma T, Johnson GH, Gordon GE. Effects of chemical disinfectants on the surface characteristics and color of denture resins. J Prosthet Dent 1997; 77(2): 197-204. 13. International organization for standardization. Technical specification 14569-1. Dental Materials – guidance on testing of wear resistance – PART I: wear by tooth brushing. Switzerland: ISO; 1999. 14. Bollen CML, Lambrechts P, Quirynen M. Comparison of surface roughness of oral hard materials to the threshold surface roughness for bacterial plaque retention: a review of the literature. Dent Mater.1997; 13(4): 258-9. 15. Kielbassa AM, Gillmann C, Zantner H, Meyer-Lueckel H, Hellwig E, Schulte-Mönting J. Profilometric and microradiographic studies on the effects of toothpaste and acidic gel abrasivity on sound and demineralized bovine dental enamel. Caries Res. 2005; 39(5): 380-6. 16. Tanoue N, Matsumara H, Atsuta M. Wear and surface roughness of current prosthetic composites after toothbrush/dentifrice abrasion. J Prosthet Dent. 2000; 84(1): 93-7. 17. Heath JR, Wilson HJ. Abrasion of restorative materials by toothpaste. J Oral Rehabil. 1976; 3(2): 121-38. 18. Frazier KB, Rueggeberg FA, Mettenburg DJ. Comparasion of wearresistance of class V restorative materials. J Esthet Dent. 1998; 10(6): 309-14. 19. Momoi Y, Hirosakil K, Kohmol A, McCabe JF. In vitro toothebrushdentifrrice abrasion of resin-modified glass ionomers. Dent Mater. 1997; 13(2): 82-8. 20. Turssi CP, Magalhães CS, Serra MC, Rodrigues Jr.AL. Surface roughness assessment of resin-based materials during brushing preceded by pHcycling simulations. Oper Dent. 2001; 26(6): 576-84. 21. Wang L, Cefaly DF, Dos Santos JL, Dos Santos JR, Lauris JR, Mondelli RF, et al. In vitro interactions between lactic acid solution and art glassionomer cements. J Appl Oral Sci. 2009; 17(4): 274-9. 22. Carvalho FG, Fucio SB, Paula AB, Correr GM, Sinhoreti MA, PuppinRontani RM. Child toothbrush abrasion effect on ionomeric materials. J Dent Child (Chic). 2008; 75(2): 112-6. 23. Coutinho E, Cardoso MV, De Munck J, Neves AA, Van Landuyt KL, Poitevin A, et al. Bonding effectiveness and interfacial characterization of a nano-filled resin-modified glass-ionomer. Dent Mater. 2009; 25(11): 1347-57. tween Rainitial and Rafinal (ΔRa) were also used for statistical analysis (α=0.05). Results: Except for the composite, significant loss of mass was observed for all glass ionomer cements and the ΔM was comparable for all of them. Significant increase in roughness was observed only for Vitremer and Ketac N100. At the end of the brushing cycle, just Vitremer presented surface roughness greater than the composite resin. Conclusion: All glass ionomer cements showed significant weight loss after 10,000 cycles of brushing. However, only Vitremer showed an increase of roughness greater than the Z350 resin, while the nanoparticulate cement Ketac N100 showed a smooth surface comparable to the composite.

Abordaje conservador y mínimamente invasivo de la hipomineralización molar-incisivo (HMI) - Relato de casos clínicos

Molar-Incisor Hypomineralization (MIH) is a qualitative developmental enamel defect that affects one to four permanent first molars, with or without involvement of permanent incisors. Enamel defects may produce many symptoms that have physical, social and psychological effects and influence day-to-day living or quality of life. The available treatment modalities for teeth with MIH are extensive, ranging from prevention, restoration, to extraction. Factors such as age, patient expectations, severity of the lesion and materials should be considered in the treatment of the patient with MIH. Restoration with composite resin is an alternative choice for posterior and anterior MIH defective teeth and its use has been show acceptable results. This article describes two clinical cases involving pediatric patients with MIH whose procedure of cavity preparation was based on the use of CVD ultrasound diamond tips and restored using composite resin obtaining favorable esthetics results after a 1 year follow-up.

Hipomineralización incisivo Y molar: diagnóstico diferencial

Hypomineralized first molar often in combination with hypomineralized incisors (MIH - molar incisor hypomineralization) is a common finding in everyday practice. In this condition, hypomineralized dental enamel is fragile and soft, and it can break easily leading to an exposed dentin, and causing dental sensitivity and progression of caries lesions. The prevalence of MIH range from 3.6 to 25% in North of Europe that consider this condition a public health problem. No conclusive information was reported about the etiologic factors of MIH, however, systemic causes seem to be of importance. Several aetiological factors are mentioned as the cause of this condition and they are frequently associated with complications during pregnancy and childhood diseases during the first three years of life. MIH is frequently misinterpreted as fluorosis, hypoplasia or amelogénesis imperfect, however, this condition presents defined clinical aspects that can distinct it from the other defects.

Hipomineralização Molar Incisivo (HMI): avaliação clínica e microscópica

This study aimed to evaluate the clinical and microscopic changes of MIH, and compare them to areas of healthy dental enamel. Methodology: epoxy resin replicas of healthy incisors and affected by MIH were evaluated qualitatively by scanning electron microscopy (SEM) photographs. Results: Clinically it was observed that MIH incisors showed changes in color and surface, with significant structural losses. By SEM, these had irregular surfaces and margins with structural losses. Conclusions: The teeth affected by HMI have clinical and morphological characteristics that are important for the definition of patient's treatment plan.

Human teeth versus bovine teeth: cutting effectiviness of diamond burs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reproducibility of microhandeness measurements in different surfices

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of standard load micro and nanopatterned in surface roughness of bleached teeth and submitted to different surface treatments?

The aim of this study was evaluate the dental enamel after whitening treatment with Opalescence Boost PF® 38%, correlating the structural alterations in the surface of the enamel with its respective pH and verify if whitened teeth submitted to different finishing and polishing techniques show similar surface texture to healthy teeth (control group). Sixty premolars were divided in 6 groups (n = 10), which had been immersed in artificial saliva during all the experiment. Protocol whitening was performed according to the manufacturer recommendations, and then the specimens were submitted to different polishing technique with Sof-Lex Pop On® disks, Flex Diamond® felt disks using two different micrometric polishing pastes (Enamelize® and Diamond Polish®) and two nanometric polishing pastes (Lummina-E Diamond and Lummina-E Alumina), according to the groups. Representative specimens were analyzed in scanning electronic microscopy (SEM). Whitening gel used in this experiment had modified the morphologic aspect of the enamel surface. It was found that two nanometric polishing pastes (G5 and G6) promoted a less rough surface compared to control group even after the whitening process.

O impacto do preparo, da cerâmica e do contato oclusal na distribuição de tensões em facetas

Pós-graduação em Odontologia Restauradora - ICT

Avaliação in vitro do efeito das tinturas de Camellia sinensis e de Aloe arborescens na remineralização de lesão de cárie artificial em esmalte dentário humano

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Penetration of hydrogen peroxide and degradation rate of different bleaching products

This study's aim was to evaluate the degradation rate of hydrogen peroxide (H2O2) and to quantify its penetration in tooth structure, considering the residence time of bleaching products on the dental enamel. For this study, bovine teeth were randomly divided according to the bleaching product received: Opalescence Xtra Boost 38%, White Gold Office 35%, Whiteness HP Blue 35%, Whiteness HP Maxx 35%, and Lase Peroxide Sensy 35%. To analyze the degradation of H2O2, the titration of bleaching agents with potassium permanganate was used, while the penetration of H2O2 was measured via spectrophotometric analysis of the acetate buffer solution, collected from the artificial pulp chamber. The analyses were performed immediately as well as 15 minutes, 30 minutes, and 45 minutes after product application. The data of degradation rate of H2O2 were submitted to analysis of variance (ANOVA) and Tukey tests, while ANOVA and Fisher tests were used for the quantification of H2O2, at the 5% level. The results showed that all products significantly reduced the concentration of H2O2 activates at the end of 45 minutes. It was also verified that the penetration of H2O2 was enhanced by increasing the residence time of the product on the tooth surface. It was concluded that the bleaching gels retained substantial concentrations of H2O2 after 45 minutes of application, and penetration of H2O2 in the dental structure is time-dependent.

Anticariogenic potencial of acidulate solutions with low fluoride concentration

Objetives: The aim of this study was to verify the anticariogenic effect of acidulate solutions with low NaF concentration, using pH-cycling model and bovine enamel. Material and Methods: Enamel blocks were submitted to the surface microhardness (SMH) test and randomly divided in 12 experimental and one placebo groups. The blocks were submitted to pH cycling for 7 days, with daily applications once/day of 0.05% NaF and 0.1% NaF and twice/day of 0.02% NaF solutions. Four different pH: 4.0, 5.0, 6.0 and 7.0 were used. Next, SMH test was again used to determine the surface microhardness percentage change (%SMH). Data obtained for %SMH were homogeneous and passed through variance analyses and Tukey's test (5%) as far as fluoride concentrations and pH. Results: The results showed that pH influenced %SMH in 0.02% NaF and 0.05% NaF solutions with pH 4.0, which had less mineral loss compared to pH 7.0 (p<0.05). The 0.02% NaF - pH 4.0, and 0.05% NaF – pH 7.0 groups showed similar results (p>0.05). A dose-response relationship was observed among the tested solutions, with better anticariogenic effect for the 0.1% NaF solution. Conclusion: The results suggest that the addition of citric acid to acidulate mouth rinses reduce mineral loss.