purpose of this in vitro study was to evaluate the effect of dimensional stability of conventionally used and advanced splinting materials on the accuracy of master casts. Materials & Methods: A reference wax model with four implants Rp-10mm was positioned in the mandibular ridge at an angulation of 00 in the anterior region and at an angulation of 450 in the posterior region using an All on 4 guide for proper orientation. A total of 8 master cast were obtained, 4 for each group and only one model was obtained from each impression. A profile projector was used to measure the linear distances. Results: Splinting the impression coping with autopolymerizing resin, adequate polymerization time and compensation procedure before impression was found to be statistically the most accurate method of splinting with its inter-implant distances showing less variation from the reference model. Discussion & Conclusion: The accuracy of the master cast obtained using direct impression technique with different splinting materials which has yielded positive results especially in relation to the use of auto-polymerizing pattern resin as it showed less amount of variation from the reference model when compared to polyvinyl siloxane so it can be more suitably used as the splinting material. After considering the various aspects of the present study and co-relating the results with the literature, it is concluded that improved accuracy of definitive cast was achieved with the use of autopolymerising resin.