Patent ID: 8882502

Claim:
A device for use in retracting a gingiva from a human tooth by widening a gingival sulcus with a dental composition, the device comprising: a cannula with a free end which comprises an opening for dispensing the dental composition, the free end and the opening being shaped so that the opening can be positioned in the entry of the gingival sulcus with an outer surface of the free end touching the tooth and the gingiva, wherein the free end is further shaped so that the gingiva is laterally displaced from the tooth as the cannula is further moved with the opening toward the inside of the gingival sulcus, wherein the cannula comprises: a first outer diameter D 1 of 0.4 mm, and a second outer diameter D 2 of 1.0 mm, wherein the first outer diameter D 1 is located at the front end of the free end, and the second outer diameter D 2 is located at a distance L 2 from the first outer diameter D 1 ; and wherein the distance L 2 is 1.0 mm; and wherein the first outer diameter D 1 is formed by the opening, the opening therefore having a first inner diameter P 1 smaller than the outer diameter D 1 ; and wherein the outer surface of the free end convexly tapers from the second outer diameter D 2 toward the first outer diameter D 1 , and wherein the convex taper in a direction from D 2 toward D 1 tapers based on a curve having a radius R which is 3.0 mm; and wherein the cannula further has a length L 1 between the first outer diameter D 1 and a third outer diameter D 3 ; and wherein the device further comprises: a container for receiving the dental composition, the container being in fluid communication with the cannula; a piston movable in the container along an extrusion path for advancing the dental composition from the container toward the cannula; and a catch extending laterally to the extrusion path and adapted to catch the device against movement in a direction parallel to the extrusion path; and wherein the device contains a dental composition which comprises: a liquid in an amount from 15 wt.-% to 30 wt.-%; a layer type 1:1 silicate mineral in an amount from 1 wt. % to 40 wt.-%; a layer type 2:1 silicate mineral in an amount from 30 wt.-% to 69 wt.-%; an astringent is present in an amount less than 25 wt.-%; and additive(s) is present in an amount less than 10 wt.-%; wt.-% with respect to the whole composition.