Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Prosthodontics

Some cases necessitate subgingival margin placement of restoration, but this should not violate the biological width to avoid gingival inflammation and recession. This is achieved by proper gingival tissue retraction to expose the finish line and reproduce it in the impression. Various techniques and materials for tissue retraction are present in the dental market. Their differences depend on amount of tissue retraction, effect on gingival tissue and quality of final impression. The aim of this study was to measure the amount of horizontal gingival tissue retraction caused by different retraction materials in vivo: Expasyl, GingiTrac and retraction cord using 3D technology (Omnicam), the gingival tissue recovery rate after retraction through measuring the level of pro-inflammatory mediator (TNF-alpha) in the gingival crevicular fluid before and 2, 7, 14 and 28 days after gingival retraction, and to evaluate the Omnicam as a method to measure the amount of tissue retraction directly in vivo. Forty volunteers with healthy gingiva were chosen for this study. Volunteers were divided into two main categories according to gingival biotype: thin and thick biotype. The areas to be measured were standardized

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