Comparison of Two Gingival Displacement Procedures; a Randomized Clinical Trial

Background: Indirect fixed prosthodontic restorations are widely used for the restoration of teeth. The fabrication of a well-fitting indirect restoration requires an accurate impression which captures the cervical finish line. Dentists have a hard time making proper impressions, with a reported 56% of impressions sent to labs being inadequate. The most common deficiency is inadequate recording of the cervical finish line. The primary reason for this inadequacy is deficient gingival displacement technique. More effective and efficient gingival displacement procedure can lead to clinically improved fixed restorations, less patient chair time, and less patient discomfort.

Materials and Methods: Sixty (60) patients will be recruited from the University of North Carolina (UNC) School of Dentistry (SOD), and they will be randomly split into 2 equal sized groups: 30 patients cordless gingival displacement procedure (Aquasil Ultra Cordless, Dentsply International); 30 patients traditional corded technique using Aquasil Ultra Polyvinyl siloxane (PVS) impression material, Dentsply International, gingival displacement cord (Ultrapak, Ultradent Products International) hydrated with aluminum chloride hexahydrate (Hemodent, Premier Dental Products Company). Patient inclusion criteria include: 1) requires indirect restoration/s. 2) probing depths 4mm or less. 3) No bleeding on probing. 4) finish line 0-1mm sub-gingival.

Specific Aims:

1. To examine if a cordless gingival displacement procedure can properly displace gingival tissue to facilitate acceptable impressions that accurately capture the prepared cervical finish line for the fabrication of indirect fixed prosthodontic restorations. These impressions will be digitally scanned, and then all of the impression scans will be evaluated for acceptability based on a set of criteria (evaluation form). The evaluations will be conducted by 2 standardized individuals.
2. To determine if a cordless gingival displacement procedure facilitates impressions that area at least as good as the traditional corded gingival displacement procedure. The impression scans will be evaluated and then a comparison will be made between the 2 groups of impressions.
3. To determine if a cordless gingival displacement procedure is more time efficient than the traditional corded procedure. All procedures will be timed, starting when the gingival displacement procedure is commenced and ending when the impression is removed from the patient's mouth.
4. To determine if a cordless gingival displacement procedure causes less trauma and discomfort to the patient than the traditional corded procedure. Patient discomfort will be evaluated with a 3 question written survey (0-10 scale answers).

The hypothesis contemplated in this proposal explores if a cordless gingival displacement procedure can properly displace gingival tissues to facilitate an acceptable impression that accurately captures the prepared cervical finish line for the fabrication of indirect fixed prosthodontic restorations. Our objective is to identify if a new procedure can improve the efficiency of a traditionally technique-sensitive procedure in dentistry.