OBJECTIVES: The use of fast-setting impression materials with different viscosities for the one-stage impression technique demands precise working times when mixing. We examined the effect of varying working time on impression precision in a randomized clinical trial. MATERIALS AND METHODS: Focusing on tooth 46, three impressions were made from each of 96 volunteers, using either a polyether (PE: Impregum Penta H/L DuoSoft Quick, 3 M ESPE) or an addition-curing silicone (AS: Aquasil Ultra LV, Dentsply/DeTrey), one with the manufacturer's recommended working time (used as a reference) and two with altered working times. All stages of the impression-taking were subject to randomization. The three-dimensional precision of the non-standard working time impressions was digitally analyzed compared to the reference impression. Statistical analysis was performed using multivariate models. RESULTS: The mean difference in the position of the lower right first molar (vs. the reference impression) ranged from ±12 μm for PE to +19 and -14 μm for AS. Significantly higher mean values (+62 to -40 μm) were found for AS compared to PE (+21 to -26 μm) in the area of the distal adjacent tooth. CONCLUSIONS:Fast-set impression materials offer high precision when used for single tooth restorations as part of a one-stage impression technique, even when the working time (mixing plus application of the light- and heavy-body components) diverges significantly from the manufacturer's recommended protocol. CLINICAL RELEVANCE: Best accuracy was achieved with machine-mixed heavy-body/light-body polyether. Both materials examined met the clinical requirements regarding precision when the teeth were completely syringed with light material.
RCT Entities:
OBJECTIVES: The use of fast-setting impression materials with different viscosities for the one-stage impression technique demands precise working times when mixing. We examined the effect of varying working time on impression precision in a randomized clinical trial. MATERIALS AND METHODS: Focusing on tooth 46, three impressions were made from each of 96 volunteers, using either a polyether (PE: Impregum Penta H/L DuoSoft Quick, 3 M ESPE) or an addition-curing silicone (AS: Aquasil Ultra LV, Dentsply/DeTrey), one with the manufacturer's recommended working time (used as a reference) and two with altered working times. All stages of the impression-taking were subject to randomization. The three-dimensional precision of the non-standard working time impressions was digitally analyzed compared to the reference impression. Statistical analysis was performed using multivariate models. RESULTS: The mean difference in the position of the lower right first molar (vs. the reference impression) ranged from ±12 μm for PE to +19 and -14 μm for AS. Significantly higher mean values (+62 to -40 μm) were found for AS compared to PE (+21 to -26 μm) in the area of the distal adjacent tooth. CONCLUSIONS: Fast-set impression materials offer high precision when used for single tooth restorations as part of a one-stage impression technique, even when the working time (mixing plus application of the light- and heavy-body components) diverges significantly from the manufacturer's recommended protocol. CLINICAL RELEVANCE: Best accuracy was achieved with machine-mixed heavy-body/light-body polyether. Both materials examined met the clinical requirements regarding precision when the teeth were completely syringed with light material.
Authors: Ralph Gunnar Luthardt; Michael H Walter; Sebastian Quaas; Rainer Koch; Heike Rudolph Journal: Quintessence Int Date: 2010 Nov-Dec Impact factor: 1.677
Authors: Manuela Haim; Ralph G Luthardt; Heike Rudolph; Rainer Koch; Michael H Walter; Sebastian Quaas Journal: Int J Prosthodont Date: 2009 May-Jun Impact factor: 1.681
Authors: Adriana Cláudia Lapria Faria; Renata Cristina Silveira Rodrigues; Ana Paula Macedo; Maria da Gloria Chiarello de Mattos; Ricardo Faria Ribeiro Journal: Braz Oral Res Date: 2008 Oct-Dec