Effect of luting cement on dental biofilm composition and secondary caries around metallic restorations in situ

Since the importance of luting cement on secondary caries in enamel and dentin is unknown, an in situ crossover study was conducted in three phases over 21 days using a fluoride-containing toothpaste. One hundred and twenty-six metallic restorations were cemented into the dentinoenamel junction of slabs of human teeth with zinc phosphate (ZP), resin-modified glass ionomer (GI) or resinous cement (RC). The slabs were inserted onto flanges of the removable partial acrylic dentures of 14 volunteers and covered with gauze to enhance dental plaque accumulation. The volunteers used fluoride toothpaste (1.100 mug F/g, w/w). After 21 days, the biofilm that formed on the slabs was collected for biochemical and microbiological analyses, and the demineralization in enamel-dentin around the restorations was evaluated. The fluoride concentration of biofilm in the GI group was higher (p<0.05) than the ZP and RC groups. Also, the concentration of Zinc in biofilm formed on the slabs cemented with ZP was higher (p<0.05) than the other groups. However, the effect of the luting material on enamel or dentin demineralization was not statistically significant (p&GT;0.05). The data suggest that when fluoride toothpaste is used, the anti-cariogenic property of the luting cement may not be relevant to the reduction of secondary caries.29550951

Effect of frequency of sucrose exposure on dental biofilm composition and enamel demineralization in the presence of fluoride

It has been suggested that enamel would resist higher frequencies of sucrose exposure if fluoride from water or dentifrice is being used. However, the effect of increasing frequencies of sugar on dental biofilm composition is not well known. Ten volunteers living in a fluoridated area wore palatal appliances bearing human enamel slabs during 14 days. The slabs were exposed to 20% sucrose solution 0 (control), 2, 4, 6, 8 or 10 times/day and the volunteers used fluoride dentifrice 3 times/day. Enamel demineralization was significantly greater than control for sucrose frequencies higher than 6 times/day. However, biofilm mass, total microbiota, total streptococci, lactobacilli counts and insoluble extracellular polysaccharide concentration increased, while Ca, P(i) and F concentration in whole biofilm decreased significantly, with frequencies of sucrose exposure lower than 6 times/day. The findings confirm that fluoride can reduce enamel demineralization if sucrose consumption is not higher than 6 times/day, but changes in the biochemical and microbiological composition of the biofilm are observed with lower frequencies of sucrose use.41191

Effect of Milk and Soy-based Infant Formulas on In Situ Demineralization of Human Primary Enamel

Purpose: The effect of infant formulas sweetened or not with sucrose on primary enamel demineralization and dental biofilm is not known. This study's purpose was to evaluate the effect of infant formula and sucrose association on demineralization of primary enamel and dental biofilm formed. Methods: A cross-over, split-mouth, and blind in situ study was conducted during 3 phases, each of 10 days duration, during which 11 volunteers wore palatal appliances containing slobs of human primary enamel. The dental slabs were extraorally subjected 8 times a day to 6 groups of treatment: distilled and deionized water; 10% sucrose solution; and milk-based and soy-based formula with or without 10% sucrose added. After each phase, the acidogenicity, biochemical and microbiological composition of dental biofilm formed was analyzed, and enamel demineralization was assessed by microhardness. Results: Both formulas induced significant enamel mineral loss, which increased when sucrose was added. Both formulas were fermented, resulting in a decrease of biofilm pH, irrespective of sucrose addition. Also, lactobacilli counts were higher in biofilm formed in the presence of both formulas when compared to the water group. Conclusions: Milk and soy-based formulas present potential to induce demineralization in primary enamel, which increased when sweetened with sucrose. (Pediatr Dent 2010;32:35-40) Received August 20, 2008 I Last Revision January 22, 2009 I Revision Accepted January 25, 2009321354

The Effect of Surface Treatments on the Micro-shear Bond Strength of a Resin Luting Agent and Four All-ceramic Systems

Objective. The current study evaluated the micro-shear bond strength between a resin luting agent and four strengthened all-ceramic systems under different surface treatments. Methods. Rectangular specimens of IPS Empress 2 (Ivoclar-Vivadent), Cergogold (DeguDent), In Ceram Alumina (Vita) and Cercon (DeguDent) ceramics were fabricated and randomly divided into three groups: 1-no treatment; 2-etched with 9.5% hydrofluoric acid and 3-airborne-particle abraded with 50 gm aluminum oxide particles. The ceramic surfaces of the specimens were coated with a silane agent (Clearfil Porcelain Bond, Kuraray), then bonded with a resin-luting agent (Panavia F, Kuraray). A micro-shear bond test was carried out to measure the bond strength. Moreover, each ceramic surface was observed morphologically by scanning electron microscopy. The results were submitted to analysis of variance and Tukey's post-hoc analysis (p<0.05). Results. The bond strength of all ceramic systems evaluated was affected by the surface treatments (p<0.05). The highest values for bond strength of IPS Empress 2 were found when the surface treatment used was hydrofluoric acid etching, followed by airborne particle abrasion treatment. On the other hand, airborne particle abrasion treatment and acid etching were not different for Cergogold and In Ceram Alumina ceramics, but they were higher when compared to the control (p<0.05). The highest bond strength to Cercon was found when it was treated with airborne particle abrasion with aluminum oxide. The SEM photographs showed that the hydrofluoric acid etching treatment affected the surface of IPS Empress 2 and Cergogold; however, Cercon and In Ceram surface morphology were not changed by the hydrofluoric acid etching. The airborne particle abrasion treatment altered the Cercon ceramic morphology but it did not change the other ceramic's surface.344399407University of Uberaba, Uberaba-MG, Brazil [PIBIC 079/2005]University of Uberaba, Uberaba-MG, Brazil [PIBIC 079/2005