Detection of artificial enamel caries-like lesions with a blue hydroxyapatite-binding porosity probe.

OBJECTIVES: This in vitro study investigated the ability of a blue protein-based hydroxyapatite porosity probe to selectively detect artificial enamel caries-like lesions of varying severities. METHODS: Artificial caries-like lesions were formed in enamel specimens using a hydroxyethylcellulose-containing lactic acid gel for 4/12/24/72 or 168 h. One untreated group was used as a control. The probe was applied for 2 min and unbound probe rinsed off with deionized water. Surface color changes were determined spectrophotometrically (L*a*b* color space) and with digital photography. Lesions were characterized using quantitative light-induced fluorescence (QLF), Vickers surface microhardness, and transverse microradiography (TMR). Data were analyzed using one-way ANOVA. RESULTS: Digital photography did not reveal any discoloration in unaffected enamel. However, all lesions stained blue with color intensity positively correlated with demineralization times. The color data reflected similar trends: lesions became significantly darker (L* decreased) and bluer (b* decreased), while overall color differences (ΔE) increased significantly after probe application (4-h lesion, mean±standard deviation: ΔL*=-2.6 ± 4.1/Δb*=0.1 ± 0.8/ΔE=5.5 ± 1.3 vs. 168-h lesion: ΔL*=-17.3 ± 1.1/Δb*=-6.0 ± 0.6/ΔE=18.7 ± 1.1). TMR analysis revealed distinct differences in integrated mineral loss (ΔZ) and lesion depth (L) between demineralization times (4-h lesion: ΔZ=391±190 vol%min × µm/L = 18.1 ± 10.9 µm vs. 168-h lesion: ΔZ=3606±499 vol%min × µm/L = 111.9 ± 13.9 µm). QLF and microhardness were also able to differentiate between demineralization times. L and ΔZ strongly correlated (Pearson correlation coefficient [r]) with Δb* (L vs. Δb*: r=-0.90/ΔZ vs. Δb*: r=-0.90), ΔE (r = 0.85/r = 0.81), and ΔL* (r=-0.79/r=-0.73). CONCLUSION: Considering the limitations of this study, the blue protein-based hydroxyapatite-binding porosity probe appears to be sufficiently sensitive to distinguish between unaffected enamel and artificial caries-like lesions. CLINICAL SIGNIFICANCE: Early detection of enamel caries lesions remains one of the most critical aspects in the diagnosis and management of dental caries. This study highlighted the potential of a novel porosity probe in detecting artificial caries-like demineralization by objective means.

Low-Income Working Families With Employer-Sponsored Insurance Turn To Public Insurance For Their Children.

Many families rely on employer-sponsored health insurance for their children. However, the rise in the cost of such insurance has outpaced growth in family income, potentially making public insurance (Medicaid or the Children's Health Insurance Plan) an attractive alternative for affordable dependent coverage. Using data for 2008-13 from the Medical Expenditure Panel Survey, we quantified the coverage rates for children from low- or moderate-income households in which a parent was offered employer-sponsored insurance. Among families in which parents were covered by such insurance, the proportion of children without employer-sponsored coverage increased from 22.5 percent in 2008 to 25.0 percent in 2013. The percentage of children with public insurance when a parent was covered by employer-sponsored insurance increased from 12.1 percent in 2008 to 15.2 percent in 2013. This trend was most pronounced for families with incomes of 100-199 percent of the federal poverty level, for whom the share of children with public insurance increased from 22.8 percent to 29.9 percent. Among families with incomes of 200-299 percent of poverty, uninsurance rates for children increased from 6.0 percent to 9.2 percent. These findings suggest a movement away from employer-sponsored insurance and toward public insurance for children in low-income families, and growth in uninsurance among children in moderate-income families.

Policy Perspective: Ensuring Comprehensive Care and Support for Gender Nonconforming Children and Adolescents.

Despite recent notable advances in societal equality for lesbian, gay, bisexual, and transgender (LGBT) individuals, youth who identify as trans* or gender nonconforming, in particular, continue to experience significant challenges accessing the services they need to grow into healthy adults. This policy perspective first offers background information describing this population, their unique healthcare needs, and obstacles when seeking care, including case study examples. The authors then provide recommendations for medical education, health systems, and insurance payers, as well as recommendations for school systems and broader public policy changes to improve the health and well-being of gender nonconforming youth.

The effect of strontium and combinations of strontium and fluoride on the remineralization of artificial caries lesions in vitro.

OBJECTIVE: To determine the effect of relatively low strontium concentrations on enamel remineralization and investigate the dose-response effects of strontium and fluoride combinations on the remineralization of artificial caries lesions in vitro. METHOD AND MATERIALS: Artificial caries lesions were created in 135 bovine enamel specimens. Lesion severity was analyzed using transverse microradiography (TMR) and quantitative light-induced fluorescence (QLF). The specimens were randomly assigned to nine treatment groups based on lesion volume after lesion creation, as measured by TMR. Treatment groups were based on a 3 x 3 factorial design (0/0.05/0.1 ppm fluoride and 0/10/15 ppm strontium). Lesions were remineralized at 37°C for 14 days in artificial saliva, which was supplemented or not with NaF and/or SrCl2 x 6H2O. Lesion remineralization was assessed using QLF and TMR. Data were analyzed using ANOVA. RESULTS: For the TMR data, lesion remineralization in the 10 ppm strontium + 0.05 ppm fluoride group was significantly higher than in all other groups (P < .05) except the 0 ppm strontium + 0.05 ppm fluoride group (P = .06). The 10 ppm strontium + 0 ppm fluoride group exhibited significantly less remineralization than the 0 ppm strontium + 0 ppm fluoride group (P = .048). For the QLF data, intergroup differences were not the same as for the TMR analysis. The QLF measurement was only moderately correlated with TMR mineral loss (r = -0.37). CONCLUSION: Strontium alone did not improve the remineralization of artificial caries lesions under the chosen in vitro conditions. However, a synergistic effect between the combination of fluoride and strontium was found at specific concentrations.

Terahertz pulsed imaging study to assess remineralization of artificial caries lesions.

We compare terahertz-pulsed imaging (TPI) with transverse microradiography (TMR) and microindentation to measure remineralization of artificial caries lesions. Lesions are formed in bovine enamel using a solution of 0.1 M lactic acid/0.2% Carbopol C907 and 50% saturated with hydroxyapatite adjusted to pH 5.0. The 20-day experimental protocol consists of four 1 min treatment periods with dentifrices containing 10, 675, 1385, and 2700 ppm fluoride, a 4-h/day acid challenge, and, for the remaining time, specimens are stored in a 50:50 pooled human/artificial saliva mixture. Each specimen is imaged at the focal point of the terahertz beam (data-point spacing = 50 µm). The time-domain data are used to calculate the refractive index volume percent profile throughout the lesion, and the differences in the integrated areas between the baseline and post-treatment profiles are used to calculate ΔΔZ((THz)). In addition, the change from baseline in both the lesion depth and the intensity of the reflected pulse from the air/enamel interface is determined. Statistically significant Pearson correlation coefficients are observed between TPI and TMR/microindentation (P < 0.05). We demonstrate that TPI has potential as a research tool for hard tissue imaging.