Comparison of bleaching effects when applied to white-spot lesions before or after resin infiltration: An in vitro study.

BACKGROUND: The purpose of this study was to compare color alterations (ΔE) of white-spot lesions (WSLs) bleached before versus after resin infiltration (RI). METHODS: Using the facial surfaces of bovine maxillary incisors, WSLs were created and the teeth were allocated into 2 groups (n = 45/group): bleach then RI (B-RI group) and RI then bleach (RI-B group). To determine ΔE, Commission Internationale de l'Eclairage L∗ a∗ b∗ (L∗ represents lightness, ranging from black to white [0-100]; a∗ represents green to red chromaticity [-150-+100]; and b∗ represents blue to yellow chromaticity [-100-+150]) measurements were obtained at baseline, after WSL formation, and after RI and bleaching. Representative specimens were evaluated by means of scanning electron microscopy. Statistical analyses included the Mann-Whitney U and Wilcoxon signed rank tests (P ≤ .0016) and repeated measures analysis of variance (P ≤ .05). RESULTS: No differences in ΔE were found comparing B-RI with RI-B groups or when the B-RI group was compared with bleached enamel. A statistically significant difference was found when the RI-B group was compared with bleached enamel (ΔE, 0.81; P < .001), but the difference was deemed not clinically significant. Scanning electron microscopy revealed that bleaching after RI increased surface roughness of the resin. CONCLUSIONS: There were no clinically significant differences in ΔE of WSLs when bleach was applied before or after RI; however, applying bleaching agent after RI roughened the surface of the resin material. PRACTICAL IMPLICATIONS: Results indicate that ΔE were not clinically significantly different between WSLs bleached before versus after RI, although it is best to sequence bleaching before RI therapy, as bleaching after RI roughened the restoration's surface.

The value of medical and pharmaceutical interventions for reducing obesity.

This paper attempts to quantify the social, private, and public-finance values of reducing obesity through pharmaceutical and medical interventions. We find that the total social value of bariatric surgery is large for treated patients, with incremental social cost-effectiveness ratios typically under $10,000 per life-year saved. On the other hand, pharmaceutical interventions against obesity yield much less social value with incremental social cost-effectiveness ratios around $50,000. Our approach accounts for: competing risks to life expectancy; health care costs; and a variety of non-medical economic consequences (pensions, disability insurance, taxes, and earnings), which account for 20% of the total social cost of these treatments. On balance, bariatric surgery generates substantial private value for those treated, in the form of health and other economic consequences. The net public fiscal effects are modest, primarily because the size of the population eligible for treatment is small. The net social effect is large once improvements in life expectancy are taken into account.

Differences in health between Americans and Western Europeans: Effects on longevity and public finance.

In 1975, 50-year-old Americans could expect to live slightly longer than most of their Western European counterparts. By 2005, American life expectancy had fallen behind that of most Western European countries. We find that this growing longevity gap is primarily due to real declines in the health of near-elderly Americans, relative to their Western European peers. We use a microsimulation approach to project what US longevity would look like, if US health trends approximated those in Western Europe. The model implies that differences in health can explain most of the growing gap in remaining life expectancy. In addition, we quantify the public finance consequences of this deterioration in health. The model predicts that gradually moving American cohorts to the health status enjoyed by Western Europeans could save up to $1.1 trillion in discounted total health expenditures from 2004 to 2050.

Patents, innovation, and the welfare effects of Medicare Part D.

PURPOSE: To evaluate the efficiency consequences of the Medicare Part D program. METHODS: We develop and empirically calibrate a simple theoretical model to examine the static and the dynamic welfare effects of Medicare Part D. FINDINGS: We show that Medicare Part D can simultaneously reduce static deadweight loss from monopoly pricing of drugs and improve incentives for innovation. We estimate that even after excluding the insurance value of the program, the welfare gain of Medicare Part D roughly equals its social costs. The program generates $5.11 billion of annual static deadweight loss reduction and at least $3.0 billion of annual value from extra innovation. IMPLICATIONS: Medicare Part D and other public prescription drug programs can be welfare-improving, even for risk-neutral and purely self-interested consumers. Furthermore, negotiation for lower branded drug prices may further increase the social return to the program. ORIGINALITY: This study demonstrates that pure efficiency motives, which do not even surface in the policy debate over Medicare Part D, can nearly justify the program on their own merits.