The clinical success of the indirect restoration requires a precise working model and thus depends on the accuracy of the final impression. An accurate impression is one of the primary determinants for a precisely fitting indirect restoration. Taking a precise impression is one of the most challenging steps in restorative dentistry, yet it is the foundation and the key to the longevity of indirect restorations. 

The need to retract the gingiva for taking impressions is universally acknowledged. The complexity of the procedure arises from a need to provide adequate horizontal space for the impression materials. Some authors have determined that the horizontal space must be between 0.2 and 0.4 mm. Gingival retraction during any stage of restoration, no matter the technique, may cause a lesion to form on the periodontal tissue. Periodontal tissue with normal healing capacity will repair itself.