Understanding the Effect of Thermal Treatment on the Physico-Mechanical Properties of Light-Cured Composites for use in Indirect Restorations.

OBJECTIVES: To study the potential benefits of a post-cure thermal treatment on key physico-mechanical properties of light-cured resin-based composites for use in indirect restorations, a CAD/CAM composite block being used as control. MATERIAL AND METHODS: Six commercial composites were light-cured before being thermally treated in a furnace at 90°C during 15 minutes (CAD/CAM composite used as a control). The properties measured with or without thermal treatment were: degree of conversion, flexural strength, elastic modulus, Vickers microHardness, organic mass content and eluted and absorbed mass before and after storage in ethanol. The data were analysed using one-way ANOVA, and Weibull distributions. RESULTS: A general increase in the properties measured was observed for all materials after thermal treatment, except a general decrease in mass elution and absorption (most statistically significant: p⟨0.05). Weibull analysis showed a tendency (p⟩0.05) of increased reliability of the flexural strength after thermal treatment for all materials. CONCLUSION: The present data revealed clear physico-mechanical improvements after thermal treatment of light-cured composites. Such method could hence be beneficially used to produce indirect restorations as compared to stratifying and light-curing the same composites in situ. However, most properties of the control CAD/CAM composite were higher, but CAD/CAM technologies aren't available everywhere.

The Hunter's Hope Krabbe family database.

The objective was to identify presenting signs and symptoms, age at onset of symptoms and diagnosis, and survival in a large population of children with Krabbe disease. In 1997, Hunter's Hope Foundation began collecting clinical data on patients who had been diagnosed with Krabbe disease. As of June 2006, 334 families had returned questionnaires. Deidentified data were analyzed, including country of origin, sex, age at onset of symptoms, symptoms before diagnosis, age at diagnosis, symptoms after diagnosis, initial diagnosis, and survival. Seventy-one percent of patients developed symptoms at 0 to 6 months of age, 19% between 7 and 12 months, and 10% at 13 months + (13 months-5.5 years). The most common initial symptoms for age 0 to 12 months were crying and irritability, stiffness, and seizures. Older children were more likely to present with gait disturbances or loss of milestones. Survival differed according to age at onset of symptoms. Children with the early infantile phenotype (onset 0 to 6 months) had significantly worse survivals than either those with onset at 7 to 12 months or at 13 months to 5.5 years. Given that neither galactocerebrosidase activity nor mutation analysis reliably predict disease severity, the data from this study should help investigators recognize the earliest symptoms of the disease, as well as increase awareness of age of onset and natural history of the various phenotypes.