Tarsus (eyelids) is a groove in the inner surface of each eyelid. Along the inner margin of the tarsus are modified sebaceous glands known as tarsal glands (or meibomian glands), aligned vertically within the tarsi: 30 to 40 glands in the upper lid, and 20 to 30 in the lower lid, which secrete a lipid-rich product which helps keep the lacrimal secretions or tears from evaporating too quickly, thus keeping the eye moist. Tarsus (eyelids) The tarsi (tarsal plates) are two comparatively thick, elongated plates of dense connective tissue, about in length; one is found in each eyelid, and contributes to its
Dental sealant issue with resin based sealants than with glass ionomer sealants. The surface is cleaned and dried. Resin sealants require an phosphoric acid solution ("etch") to create microscopic porosity into which the sealant material can flow thereby increasing retention, increasing surface area and improving the strength of the bond between the sealant and the tooth surface. Etching time varies from 15 to 60 seconds, depending on the product. After that, the tooth must be rinsed and dried thoroughly for 15 to 20 seconds. Chalky appearance on the dried tooth means the tooth has been properly etched. If the tooth does not