A laboratory study on the dimensional accuracy of some of the impression materials used in fixedpartial denture prosthesis Sharma M.R., Principal, Professor and HOD Address for Correspondence: Dr. M.R. Sharma, Principal, Dept. of Prosthodontic, Maharaja Ganga Singh Dental College & Research Centre Sriganganagar (Rajasthan)
Online published on 25 November, 2013. Abstract This study did not envisage an investigation which would indicate dimensional accuracy of impression materials in terms of absolute values. The scope of the present study was restricted to making comparison of the dimensional accuracy of different impression materials as used in the recording of impressions in Crown & Bridge Prosthesis. To achieve these impressions of a master die were obtained in different impression materials & from the stone dies so obtained a dimensional comparison was made with the master die. Materials & Method The method consisted in preparing stone dies from some of the impression materials used in the field of Crown and Bridge prosthesis and comparing their dimensions with a master die so as to evaluate the accuracy of reproduction of the impression materials. For conducting this study a special die was prepared. The master die was shaped like a Jocket crown stump preparations and was made of brass and gold plated so as to get a smooth surface finish and to make it resistant to tarnish and corrosion. In order to standardize the procedure of impression recoding of the die, a special impression device was fabricated. The impressions of the master die were obtained using different impression materials i.e. irreversible hydrocolloide, polyeather, silicone and low fusing compound. A total of 15 impressions were obtained each impression material. The stone dies were measured using a travelling microscope to an accuracy of 0.01 mm. Results The results of the study showed polyeather to be the most accurate impression material followed by silicone & irreversible hydrocolloide. Low fusing compound was found to be least accurate material. Summary & Conclusion In order of preference, the most accurate material was polyether followed by alginate & silicone impression materials. The least accurate impression material was found out to be low fusing composition. Top |