Hydrogen peroxide is an oxidative agent commonly used for dental bleaching procedures. The structural and biochemical responses of enamel, dentin, and pulp tissues to the in vivo bleaching of human (n = 20) premolars were investigated in this study. Atomic force microscopy (AFM) was used to observe enamel nanostructure. The chemical composition of enamel and dentin was analyzed by infrared spectroscopy (FTIR). The enzymatic activities of dental cathepsin B and matrix metalloproteinases (MMPs) were monitored with fluorogenic substrates. The amount of collagen in dentin was measured by emission of collagen autofluorescence with confocal fluorescence microscopy. The presence of Reactive Oxygen Species (ROS) in the pulp was evaluated with a fluorogenic 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) probe. Vital bleaching of teeth significantly altered all tested parameters: AFM images revealed a corrosion of surface enamel nanostructure; FTIR analysis showed a loss of carbonate and proteins from enamel and dentin, along with an increase in the proteolytic activity of cathepsin-B and MMPs; and there was a reduction in the autofluorescence of collagen and an increase in both cathepsin-B activity and ROS in pulp tissues. Together, these results indicate that 35% hydrogen peroxide used in clinical bleaching protocols dramatically alters the structural and biochemical properties of dental hard and soft pulp tissue.

Cement-based materials, such as concrete and mortars, are used in extremely large amounts.

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The efficacy of interventions using distance approaches in the cancer setting is still not well-established. Further research should be conducted through well-designed studies with more interactive features that minimize the lack of face-to-face interaction. Implications for rehabilitation Rehabilitation professionals working in the field of oncology should invest in the development of psycho-educational interventions responding the patients' educational needs and promoting their stress control skills. Programs using telecommunications technologies may reduce disparities in service delivery within this setting, minimizing geographic and socio-economic barriers to engagement in the interventions. With the current technological development, it is possible to perform more interactive interventions that stimulate therapist-patient interactions. However, available protocols in this field still employ basic resources (e.g., websites, e-mail, and videos). Young adult cancer patients are exposed to additional requirements related to fertility and parenthood. New intervention approaches should consider their informational needs.

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