Introduction: Dimensional accuracy of impression materials is crucial for the production of working casts in Fixed Prosthodontics. The accurate replication of tooth preparations and their arch position requires impression materials that exhibit limited distortion. Methods:This study was conducted to comparatively evaluate the dimensional accuracy of additional silicones by comparing two different techniques and spacer designs, by measuring the linear changes in interpreparation distance. The impressions were made from a stainless steel master die simulating a three unit bridge. A total 80 die stone (type IV, Ultrarock) models were obtained from the impressions made using two different parameters. The two different parameters are Multimix and Monophasic technique and different spacer designs. Result:The interpreparation distance of the abutments in the casts was measured using a travelling microscope. Each sample was measured thrice and the mean value was calculated. The results obtained were statistically analysed and the values fall within the clinically acceptable range.

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Treatment of persistent macular holes is a challenge. Various techniques have been devised to reduce the surgical failure rate. We present a case of persistent macular hole treated with human amniotic membrane (hAM). We performed primary 23 Gauge pars plana vitrectomy surgery with internal limiting membrane peeling and perfluoropropane (C3F8) gas. Two weeks postoperatively, spectral domain optical coherence tomography (SDOCT) showed an open macular hole. A secondary surgery using hAM plug as scaffold and C3F8 gas was performed. Three weeks postoperative follow-up SDOCT showed anatomical closure of the macular hole. This suggests that hAM can be an effective substrate for persistent macular holes.