Effect of commercial fluoride dentifrices against hydrochloric acid in an erosion-abrasion model.

OBJECTIVES: This study assessed the effect of three commercial dentifrices with different fluoride-containing compounds in controlling the progression of dentin loss using an in vitro erosion-abrasion model. MATERIALS AND METHODS: Dentin specimens were randomized into four groups (n = 10): control (no F), Elmex (1,400 ppm AmF), Meridol (1,400 ppm AmF/SnF2), and Crest Pro-Health (1,100 ppm SnF2). The dentin specimens were submitted to cycles of demineralization (HCl 0.01 M for 60 s), remineralization (artificial saliva for 60 min), and immersion in 1:3 w/w of dentifrice/artificial saliva, followed by toothbrushing (150 brushing strokes). The cycle was repeated three times daily for 5 days. Surface loss was quantified by stylus profilometry. Data were submitted to one-way ANOVA and Tukey's tests (p < 0.05). RESULTS: Wear (µm ± SD) was control 4.1 ± 1.2, Elmex 3.7 ± 1.5, Meridol 1.3 ± 0.4, and Crest Pro-Health 2.1 ± 0.7. Therefore, all products (except Elmex) produced statistically significantly less mineral loss (p < 0.05) when compared with the control. CONCLUSION: None of the dentifrices avoided the erosive-abrasive process; however, SnF2-containing dentifrices were effective in statistically significantly reducing dentin loss. CLINICAL RELEVANCE: Scientific literature shows evidence that fluoride can strengthen dental tissue against erosive acid damage. However, the beneficial effect of different fluorides present in commercial dentifrices is questionable. Thus, a determination of an effective fluoride dentifrice may be beneficial in the reduction of the erosive process in patients with gastric disorders.

Environmental pH influences Candida albicans biofilms regarding its structure, virulence and susceptibility to fluconazole.

Candida albicans colonizes sites with different environmental pH. However, it is unclear how these conditions can interfere on biofilms. This study aimed to evaluate the influence of environmental pH on behavior of C. albicans regarding its structure, virulence and susceptibility to fluconazole (FLZ). Minimal inhibitory concentration, minimal fungicidal concentration and time kill were used to evaluate the susceptibility to FLZ in planktonic cells under three pH values (4.0, 5.5, 7.0). These pH values were used for biofilms analysis. C. albicans ATCC 90028 was developed on poly(methlymethacrylate) resin for 48 h. Then, 2.56 µg/mL of FLZ was added to experimental groups for 24 h, and biofilms were analyzed by cell quantification, bioactivity, secretion of proteinases and phospholipases and structure. All data were analyzed by two-way ANOVA, followed by Tukey's test (α = 0.05). For planktonic cells, changes in environmental pH decreased the susceptibility to FLZ. C. albicans biofilms developed at pH 5.5 showed higher cell counts, bioactivity, bio-volume, average thickness and roughness coefficient (p < 0.05). In contrast, the presence of FLZ at pH 4.0 did not influence the structural parameters (p > 0.05), but increased secretion of proteinase and phospholipase (p < 0.05). Within the conditions studied, it was shown that environmental pH modulates the structure, virulence and susceptibility of C. albicans to FLZ.

Total rehabilitation of maxilla using a tooth-to-implant restoration: case report.

Dental implants in partially edentulous patients are a predictable therapeutic option. However, using tooth-to-implant restorations to rehabilitate partially edentulous patients involves highly complex biomechanical aspects. This type of prosthesis utilizes different kinds of support that react distinctly to the functional forces developed in the oral cavity. In some cases, a tooth-to-implant restoration is a treatment option for difficulties related to reduced bone volume, inadequate interdental space, or an implant's failure to osseointegrate. This case report describes the rehabilitation of a patient whose partially edentulous maxilla was treated with a tooth-to-implant restoration. In this case, telescopic crowns were used to better match the tooth-implant union. No biomechanical or functional problems were found 8 years post-treatment, indicating that the combination of implant and tooth support is a possible treatment option with an improved long-term prognosis.

Dietary carbohydrates modulate Candida albicans biofilm development on the denture surface.

The purpose of this study was to investigate whether dietary carbohydrates can modulate the development of Candida albicans biofilms on the denture material surface. Poly (methyl methacrylate) acrylic resin discs were fabricated and had their surface roughness measured. Biofilms of C. albicans ATCC 90028 were developed on saliva-coated specimens in culture medium without (control) or with carbohydrate supplementation by starch, starch+sucrose, glucose, or sucrose for 72 h. The cell count, metabolic activity, biovolume, average thickness, and roughness coefficient were evaluated at the adhesion phase (1.5 h) and after 24, 48, and 72 h. The secretion of proteinases and phospholipases, cell surface energy, and production of extra/intracellular polysaccharides were analyzed after 72 h of biofilm development. Data were analyzed by one- and two-way ANOVA followed by Tukey's test at 5% significance level. In the early stages of colonization (adhesion and 24 h), the glucose group showed the highest cell counts and metabolic activity among the groups (p<0.05). After maturation (48 and 72 h), biofilms exposed to glucose, sucrose, or starch+sucrose showed higher cell counts and metabolic activity than the control and starch groups (p<0.001). Compared to the control group, biofilms developed on starch or starch+sucrose had more proteinase activity (p<0.001), whereas biofilms developed on glucose or sucrose had more phospholipase activity (p<0.05). Exposure to starch+sucrose increased the production of extracellular and intracellular polysaccharides (p<0.05). Biofilms developed on starch or without carbohydrate supplementation presented cells with more hydrophobic behavior compared to the other groups. Confocal images showed hyphae forms on biofilms exposed to starch or starch+sucrose. Within the conditions studied, it can be concluded that dietary carbohydrates can modulate biofilm development on the denture surface by affecting virulence factors and structural features.