Why do Gluma Desensitiser and Gluma Desensitiser PowerGel need to be rinsed off?

Rinsing off Gluma Desensitiser

GLUMA Desensitizer and GLUMA Desensitizer PowerGel contain glutardialdehyde. This substance is responsible for the effective reduction of dentine hypersensitivity. It is a highly reactive agent able to coagulate proteins. This effect is desired within the dentine tubuli but not on the gingiva and mucosa. We therefore strongly recommend the use of rubber dam. To avoid irritation of oral soft tissues, GLUMA Desensitizer and GLUMA Desensitizer PowerGel must never touch soft tissue and must be rinsed off with plenty of water by the dentist/dental assistant.