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Three UEDMA/TEGDMA (50:50 by weight) based dental composites were made, each with filler loadings of 53 vol.%. The three composites contained silane-treated filler particles with average particle diameters of 1.5, 3.0, or 10.0 microm. Twelve specimens per composite were mounted on wear wheels and run through 200,000 cycles in an ACTA wear machine. Six of these specimens per material were worn in slurries consisting of 30 g ground Millet seed shells and 120 g ground rice mixed with 275 mL water. The remaining six specimens were worn in similar 25% ethanol-water slurries. The composite wear profiles were recorded with a profilometer and used to calculate the wear. Hardness values of the composites were also measured both before and after storage for 2 weeks in either water or in a 25% ethanol water solution. The wear and hardness values from the measurements were analyzed using ANOVA. The wear analysis showed that the finer composites (1.5 microm filler diameter) wore the least and the coarsest composites (10 microm filler diameter) the most. The wear was significantly higher in the ethanol water slurry than in the water slurry. The hardness value of the coarsest composite decreased more than the finest composite during storage in water or 25% ethanol water. The hardness decrease was most pronounced in the alcohol solution. [ABSTRACT FROM AUTHOR]

Studies in the Scandinavian countries have shown that orthodontists run an equal or even greater risk of contracting dermatitis compared to other dental personnel. The aim of the study was to find out whether the self-reported occupation-related health problems of general dental practitioners and orthodontists differ from those of office employees in Finland. The subjects were 147 general dentists, 81 orthodontists and 99 office employees (77% women and 23% men). The data were collected using a mailed questionnaire. Within the past year, 42% of the subjects had had occupational health problems, while 51% had experienced symptoms in the previous year or earlier. The complaints of hand dermatoses, musculoskeletal, as well as respiratory symptoms were significantly more common among women than among men. Musculoskeletal complaints were the most common symptoms in all occupational groups, but the odds ratio of having them were significantly higher for dental professionals compared to office employees. The frequency of self-reported hand dermatoses was 42% for dental professionals and 26% for office employees, but the difference did not reach statistical significance. The odds of having hand dermatoses were higher for atopic subjects and for women. Orthodontists did not differ from general practitioners in respect of any of the complaints reported. Materials used in dentistry were mentioned as the cause of symptoms by 49 (21.5%) of the dental professionals. The present results show an increased risk of self-reported musculoskeletal symptoms for the dental professionals. Also, a tendency towards increased occurrence of skin symptoms was noted for the dental professionals compared to office employees of this study. [ABSTRACT FROM AUTHOR]