To know when and how to use liners, bases, and perform an indirect pulp cap.
This is important to help protect the tooth and increase the longevity of the restoration.
1. Teaching Point: Apply Cavity Varnish
The Instructor will take a dentoform with a class 1 cavity preparation and demonstrate the application of a cavity varnish such as Copalite by:
Apply twothincoats. A cotton pledget, cut in half, can be used with cotton pliers to wipe or paint all the cavity walls. Air-dry in between the layers to evaporate the chloroform. The second coat ensures that all the dentinal tubules are sealed. The preparation will look shiny or wet.
PRACTICAL – students will use one of the class 1 preparation on the dentaform and duplicate the instructor. The instructor will verify this has been done correctly – this will be the informal EC,
2. Teaching Point: Placing Cavity Liners as Indirect Pulp Cap
The Instructor will use a dentaform with class 2 cavity preparation and matrix band /wedge in place. The instructor will show the student how to mix and apply Calcium Hydroxide (Dycal), and Glass Ionomer on both the pulpal floor and then on the axial wall. The Instructor will reinforce that this should only be attempted for INDIRECT PULP CAPPING. The technique is as follows:
The first liner will be the Calcium Hydroxide.
Equal small amounts of base and catalyst are placed on a paper mixing pad andmixed withaspatula within 10 seconds until the paste is smooth and homogeneous.
The mixed material will set in 21/2 to31/2 minutes on the mixing pad (or less if the room temperature is hot).
Work quickly - take a Dycal applicator and scoop up a small amount of the Dycal on the ball of the applicator and apply to the dentine. If you quickly the Dycal will have better flow characteristics.
Avoid touching the margins of the cavity
Avoid placing a large bulk of material
The second liner will be glass ionomer
One level scoop of loosely packed powder to one drop of liquid (must confirm with the specific product you are using)
The powder/liquid ratio of the mix may be varied to change the viscosity needed. Ratios ranging from 1 scoop powder/2 drops liquid to 2 scoops powder/1drop liquid are acceptable.
Rapidly mix (10-15 seconds) all powder and liquid
Place in ½ mm increments up to .75 mm thick. Placeondentinonly. Donotcoverthe wallsof thepreparation.
Light cure for 30 seconds
PRACTICAL – students will use one of the class 2 preparation on the dentaform and duplicate the instructor. The instructor will verify this has been done correctly – this will be the informal EC.