Evaluation and comparison of dimensional accuracy of conventional alginate and alginate alternative at different time intervals- An in vitro study

Objective: The purpose of the study was to evaluate and compare the linear and cross arch dimensional accuracy of conventional alginate (Algitex) and alginate alternative ( AlgiNot) at different time intervals. Materials and Methods: Thirty two impressions of full arch master model were made with both the materials and they were divided into four groups: immediate pour, poured at24 hours, 96 hours,and 120 hours. Anterio posterior (A-B& A-C) and cross arch (B-C) measurements were made on the casts with the help of coordinated measuring machine. Results: Alginate Alternative (AlgiNot) produced the casts with minimum distortion at each time interval. Conventional alginate (Algitex) produced accurate casts when impressions were poured immediately. There was an increase in distortion at each time interval for conventional alginate. At the end of 120 hrs conventional alginate showed 3.67% increase in A-B (antero posterior)dimension, 3.53% increase in A-C (antero posterior) dimension and 2.18% in B-C (cross arch) dimension. At the end of 120 hrs alginate alternative showed 1.7% increase in A-B (antero posterior) dimension, 1.3% increase in A-C (antero posterior) dimension and 0.62% in B-C (cross arch) dimension. Conclusion: Dimensional changes were evident with both the materials tested in the study at the end of 120 hours. Conventional alginate (Algitex) and Alginate Alternative (AlgiNot) both produced accurate casts at immediate pour. Conventional alginate (Algitex) showed marked dimensional changes at 24hours, 96hours, and 120 hours. Whereas, Alginate Alternative (AlgiNot) showed less significant changes at 24hrs, 96hrs and 120 hrs.