Comparative Effect of Various Border Molding and Final Impression Materials of Altered Cast Impression Technique on Tissue Displacement of Mandibular Distal Extension Cases

Background The functional impressions for tissue supported partial dentures require recording the functional form of the residual ridge under occlusal loading. Aim of study is to measure the amount of vertical tissue displacement by using different impression and border molding materials used in altered cast impression technique. Materials and method Ten patients were selected with unilateral edentulous span in mandibular arch with at least first premolar and all anterior teeth were remain. Patient was subjected to three different altered cast impression procedures using the low fusing compound as border molding and zinc oxide eugenol as final impression material which is considered as a control for comparison with other groups that border molded with putty type silicone and final impression made with light and very light silicone impression material Standardized acrylic occlusal platform was constructed and at three points of the edentulous span the vertical tissue displacement occurring due to different impression procedure was measured. Results indicated that when an altered cast impression technique using light body silicone final impression material with putty type silicone border molding material resulting in higher amount of tissue displacement when compared to zinc oxide eugenol impression material and very light body silicone final impression material in all examined points. Conclusion An altered cast impression technique using the putty type silicone as border modeling and very light body silicone as a final impression material producing a little amount of tissue displacement as compared to other groups and A greatest displacement was produced at the point C which represent the center of retromolar pad area.