Theapplication Of Different Gingival Retraction Methods For Porcelain-fixed Prosthodontics

Objective: This research aims to compare clinical effects regarding severalgingival retraction methods in porcelain-fixed prosthodontics.Material and Methods:37patients requiring porcelain-fixed prosthesis wereincluded in the study from Mar.2012to Mar.2013,Totally60teeth (anterior teeth:38posterior teeth:22) with healthy periodontal condition were evaluated, among which36teeth with normal clinical crown height as well as without gingival defect;14residualroots;10teeth with short clinical crown height. After preparation, we randomly dividedall of teeth prepared into four groups with four gingival retraction methods (the singlecord technique; the double cord technique; retraction assisted by temporary crown;gingival retraction paste)and each group contained15teeth. After the gingivalcontraction, making impression with silicon rubber or agar and alginate combinationimpression material immediately, then we made plater cast. Finally all the teeth、gums、impressions and casts were visually inspected and evaluated by one dentist.Results: In the sample of teeth with normal clinical crown height as well aswithout gingival defect, the rate up to standard of the double cord technique, retractionassisted by temporary crown, gingival retraction paste was higher than the single cordtechnique respectively. While retraction assisted by temporary crown, gingivalretraction paste reached higher rate in the sample of residual roots and teeth with short clinical crown height.Conclusion: the double cord technique, retraction assisted by temporary crown,gingival retraction paste could achieve desired effect of gingival retraction; Either themethod of retraction assisted by temporary crown or gingival retraction paste reachesbetter effect in the case of residual root and tooth with short clinical crown height.