Rui Fernando Mazur

Analysis of the association between lactotransferrin (LTF) gene polymorphism and dental caries

Objective The present study evaluated the association between lactotransferrin (LTF) gene polymorphism (exon 2, A/G, Lys/Arg) and dental caries. Material and Methods A convenience sample of 110 individuals, 12 years old, was divided into: group 1, 48 individuals without caries experience (DMFT=0), and group 2, 62 subjects with caries experience (DMFT≥1). DNA was obtained from a mouthwash with 3% glucose solution, followed by a scrapping of the oral mucosa. After DNA purification, polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) was performed to access the study polymorphism. The LTF A/G (Lys/Arg) polymorphism had been previously reported as located in exon 1. Results Allele 1 of the study polymorphism was associated with low DMFT index and showed a protective effect against caries experience (OR=0.16, IC=0.030.76, p=0.01). Conclusion Lactotransferrin A/G (exon 2, Lys/Arg) polymorphism was associated with susceptibility to dental caries in 12-year-old students.

Effect of open-sandwich vs. adhesive restorative techniques on enamel and dentine demineralization: An in situ study

OBJECTIVES To assess in situ the effect of different restorative techniques used with fluoride-releasing materials on enamel and dentine demineralization in the presence of a cariogenic challenge. METHODS Thirty human molars were prepared for 60 Class V cavities, with enamel and dentine margins. The teeth were divided into four groups (n=15): L1 - open sandwich technique with a conventional glass ionomer cement (GIC), L2 - open sandwich technique with a resin-modified GIC, A1 - total-etch bonding with a fluoride-containing adhesive, A2 - total-etch bonding with a nonfluoride-containing adhesive. All the cavities were restored with a nanofilled composite. Fifteen volunteers used appliances containing one specimen from each group. The cariogenic challenge was carried out with a 20% sucrose solution 8×/day for 7 days. The specimens were sectioned for microhardness test and EDS analysis at different depths below the enamel and dentine margins (25, 50 and 100μm) and distances from the tooth-restoration interfaces (25 and 75μm). The data were analyzed by ANOVA and Games-Howell test (α=5%). RESULTS Both GICs produced higher hardness in enamel at all depth-and-distance combinations, but only L1 produced higher hardness in dentine (p<0.05). L2 and A1 exhibited similar dentine hardness at 25μm distance for all depths (p>0.05). L1 demonstrated significantly higher amounts of calcium in dentine than the other groups, but had similar amounts in enamel to L2 and A1. CONCLUSIONS The open sandwich technique using conventional GIC proved more effective in reducing enamel and dentine demineralization at depths of up to 100μm under a cariogenic challenge. CLINICAL SIGNIFICANCE Conventional GICs should be considered the materials of choice for lining of cavities not having all margins in enamel, particularly using the open sandwich technique.

Specific concentration evaluation of 16% carbamide peroxide compounded at dispensing pharmacies

The aim of this work was to evaluate the concentration of carbamide peroxide compounded at different dispensing pharmacies. Immediate concentration analysis was made of bleaching gels dispensed by specialized pharmacies, and of a commercially available gel (control group) (n=20). The carbamide peroxide concentration was determined by titration and the results were analyzed statistically by the Kruskal-Wallis test. The commercial bleaching agent (control group) and one of the gels from the pharmacies presented the best mean concentration values, close to 16%. In conclusion, the concentration of the manipulated and industrialized carbamide peroxide gels presented concentration values differing from 16%.

Effect of desensitizing agents on the microtensile bond strength of two-step etch-and-rinse adhesives to dentin.

Desensitizers can be used to control postoperative sensitivity in adhesive restorations. The aim of this study was to evaluate the effect of desensitizing agents on the bond strength of two-step etch-and-rinse adhesive systems to dentin. Forty-two human molars were sectioned to obtain 3-mm-thick dentin discs. The discs were divided into three groups (n = 14 in each) - no-treatment control group (CT), and oxalic acid [BisBlock (BB)] and calcium phosphate [Desensibilize Nano-P (NP)] desensitizers - before the application of two adhesive systems [Adper Single Bond Plus (SB) and One-Step Plus (OSP)]. A nanoparticle composite resin was used to create a 3-mm-thick build-up. The specimens were stored in distilled water for 24 h before a microtensile bond-strength test was performed. The failure modes were determined using a stereomicroscope at 100 × magnification. Specimens were sectioned perpendicular to the interface for scanning electron microscopy analyses. The CT-SB group exhibited the highest bond strength, differing significantly from BB-SB and BB-OSP groups. Mixed failures were prevalent for all groups. Scanning electron microscopy revealed a continuous hybrid layer and resin tags in all groups. Dentin bond strength of etch-and-rinse adhesive systems was reduced by an oxalic acid desensitizer but was not affected by a calcium phosphate-containing desensitizer.

Análise comparativa de dois produtos de higienização de próteses totais na remoção do biofilme

Introducao: A higiene das proteses totais e importante na prevencao de doencas cardiacas e pulmonares em pacientes idosos. Objetivo: Comparar a eficacia dos metodos de higienizacao para proteses totais. Materiais e metodos: Foram selecionados 20 pacientes portadores de proteses totais superiores. As proteses foram coradas com fucsina basica e, posteriormente, divididas em dois grupos de acordo com as solucoes de higiene: grupo 1 – Corega Tabs® (CT); grupo 2 – hipoclorito de sodio (HS) 2,5%. No grupo 1, as proteses foram submersas em 250 mL de agua destilada + 1 pastilha de Corega Tabs, no Grupo 2, em 250 mL de agua destilada + 10 mL de hipoclorito de sodio a 2,5% por 5 minutos. Apos a imersao, foi escovada a porcao interna das proteses por um minuto. As bases internas das proteses foram coradas e fotografadas. Em seguida, realizaram-se imersao e imersao + escovacao, e entao, foi avaliada a quantidade de placa bacteriana pelo metodo da contagem de pontos. Os dados foram analisados pelos testes t de Student, ANOVA e multiplas comparacoes de Tukey HSD. Resultados: Foram encontradas diferencas significativas entre a quantidade de placa bacteriana inicial e apos imersao + escovacao para ambos os grupos (CT, 40,12 ± 22,44 e 10,92 ± 11,39; HS, 40,64 ± 24,12 e 13,06 ± 11,08; p 0,05). Conclusao: CT e HS nao apresentaram diferencas para eficiencia na remocao de placa bacteriana. O metodo de imersao + escovacao mostrou-se o mais eficaz na remocao de placa bacteriana em proteses totais superiores.