DIMENSIONAL ACCURACY OF VARIOUS IMPRESSION MATERIALS AND TECHNIQUES OF DENTAL IMPLANT AT SECOND STAGE SURGERY- A COMPARATIVE STUDY

Dr. Nimra Mehraj* and Dr. Rofadun Nisa

ABSTRACT

Introduction: For long term clinical success of the implant prosthesis, fabrication of precisely fitting implant-retained prostheses is of great importance. Several impression techniques using different impression materials have been suggested to ensure the passive fit of a prosthesis on osseointegrated implants. Thus, a study to compare the dimensional accuracy among different impression materials using different impression techniques was undertaken. Material and method: A master stainless framework with 3 internal hex implants was fabricated and used to generate the samples. This assembly was duplicated in lab duplicating silicone and all the trays were fabricated on this duplicated silicone die using light cure acrylic resin. Samples were divided into 9 groups each having 5 samples. Impressions using all the techniques and materials were carried and were poured in type IV gypsum product. The master cast thus generated was then used to measure the interimplant distance using stereomicroscope and an image analyzing software, Material Plus pro. Result: The mean difference was found to be statistically not significant (p-value>0.05) for the material and techniques taken together. Whereas the result was statistically significant (p-value<0.05) when the materials and techniques were taken separately. Conclusion: Polyvinylsiloxane-polyether Hybrid impression material and Open tray Non Splinted technique gives best replication of the implant positions on the master cast and the use of this combination is encouraged whereas Polyvinylsiloxane impression material and Closed tray technique results in a large mean difference in interimplant distance and thus should be avoided as far as possible for the use of implant impressions.

Keywords: POLYVINYLSILOXANE; POLYETHER, HYBRID IMPRESSION MATERIAL; CLOSE TRAY TECHNIQUE; OPEN TRAY TECHNIQUE.