indication. impressions to ensure accurate recording of the preparation and finish line, gingival retraction is needed. its use displaces the gingival tissues long enough to allow the impression material to flow down below the margin preparation lines and into the orifice. the use of the gingival retraction cord is a safe method as when used correctly will not harm the gingival tissues whilst ensuring the detail recorded is of good quality. the various types of gingival retraction cords that can be used are twisted, braided and knitted. the use of all three requires pre-soaking in either water or an agent that encourages haemostasis. the haemostatic agent controls gingival haemorrhage following the preparation and prior to impression making. once the cord has been left in place for the required length of time, it is removed allowing the sulcus to be rinsed and dried in order to prevent the haemostatic agent from creating problems with the set of the impression material. the two methods used for making impressions for post and cores are outlined below. direct technique the material used with the post to create the pattern for both the post and core is a self-cure acrylic resin the wall of the canal is lubricated before the self-cure resin is placed within the intra-radicular portion of the canal around the post to ensure it has adhered and adapted to the post correctly once set, the post is removed and examined for deficiencies. if any deficiencies are present that are not minor enough to be managed with wax, a remake of the impression will be required once satisfied with the post, the core portion is built-up before it is refined to achieve the desired shape the occlusal clearance is assessed and the pattern is examined for a final time before sending to the laboratory for casting indirect technique the post is bevelled to ensure a better fit within the canal as the preparation for the post will end in a point due to the instruments used for the preparation the post is then seated to the correct length and tested to confirm it resists displacement the occlusal end is trimmed until it is at the same level as the adjacent teeth and is made retentive with the use of a heated instrument. lubricant is painted on the portion lying within the canal to aid its removal gingival retraction as described above is completed a light bodied addition silicone material is syringed in the orifice and around the prep ensuring the prep is completely covered, before a heavier bodied addition silicone material in a stock tray is seated over the prep to make the impression of the full arch once set the impression should be removed with the post embedded in-situ finally, an impression is made of the opposing arch