An evaluation of the time-dependent dimensional stability of eleven elastomeric impression materials

Williams, Peter T.; Jackson, Dionne; Bergman, W.

doi:10.1016/0022-3913(84)90194-x

Cited by 67 publications

(49 citation statements)

References 13 publications

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“…However some authors have mentioned that if the thickness of light body is less than 1mm then also the dimensional accuracy of the impression is affected 11,12 . Difference in dimensions of samples poured at 1 hour, 24 hours and 48 hours was not significant, this observation was found to be clinically irrelevant because, polyvinyl siloxane impression materials are not susceptible to changes in humidity, and they do not undergo any further chemical reactions or release any byproducts 13 . This result is in agreement with other studies which concluded that addition silicone impression show no dimensional changes after 24 hours 13 , 1 week 14 , 2 weeks 15 and even 3 months 16 .…”

Section: Discussionmentioning

confidence: 82%

Dimensional Accuracy and Stability of Silicone Putty Wash Impression Technique with Different Thickness of Light Body Material

Mubashir¹,

Motwani²,

Sahu³

et al. 2015

J Cont Med A Dent

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Section: Discussionmentioning

confidence: 82%

Dimensional Accuracy and Stability of Silicone Putty Wash Impression Technique with Different Thickness of Light Body Material

Mubashir¹,

Motwani²,

Sahu³

et al. 2015

J Cont Med A Dent

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“…The dimensional stability of elastomeric impression materials is influenced by shrinkage caused by polymerization, the byproducts of chemical reactions, thermal changes and incomplete elastic recovery from deformation 6,7,9) , while factors such as impression disinfection 24,25) , pouring time 26,27) and the impression technique 6,11,12,15) affect the accuracy. The present work is one of the few studies to directly assess the accuracy and dimensional stability of a thin impression margin (1×0.2 mm) over time using a reproduction of the finish line and emergence profile on the impression material itself.…”

Section: Discussionmentioning

confidence: 99%

Dimensional stability of polyvinyl siloxane impression material reproducing the sulcular area

et al. 2013

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The dimensional stability of a thin intra sulcular impression material reproducing the preparation finish line was evaluated. Impressions were taken of a stainless-steel master model of a simulated abutment with a 'gingival sulcus' using Express regular, Express fast and Aquasil. The putty-wash two-step technique was applied with spacer thicknesses of 0.5, 1 and 1.5 mm. Mid mesiodistal and bucco-lingual measurements were taken directly from the sulcular impression material after 0.5, 2, 24, 48 and 72 h via a Toolmaker's microscope. The discrepancies between the measurements of the impression material and the master model were calculated. The discrepancies changed significantly over time (p<0.001). The use of a 0.5 mm spacer resulted in a negative deviation from the model (2-46 µm), minimally after 2 h. The use of 1 and 1.5 mm spacers showed a positive deviation from the model (21-52 µm) and both are equally recommended. Investment can be postponed until 72 h.

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“…Accuracy is lost with extended periods of time (Schen, 2003;Donovan and Chee, 2004), because of lack of dimensional stability. Polyether and polyvinyl siloxane are accurate for 1 -2 weeks, whereas polysulfide is accurate if the impression is casted within between 1 -2 hours (Williams et al, 1984;Schen, 2003) of impression making. Therefore, should pouring be delayed, it is advisable to use addition-silicone or polyether materials, which have the smallest dimensional change over time.…”

Section: Dimensional Stabilitymentioning

confidence: 99%

“…The shrinkage for these two products is lower because there is no loss of by-products. (Williams et al, 1984;Anusavice, 2003;Donavan and Chee, 2004) Addition-silicones acquire almost the ideal dimensional stability because there are no by-products formed during the chemical setting reaction. It can be poured immediately after the impression has been removed from the oral cavity, or days after impression making and can still produce an accurate cast if poured within 1 -2 weeks (Donovan and Chee, 2004).…”

Section: Dimensional Stabilitymentioning

confidence: 99%

The effect of temperature on linear dimensional stability of elastomers

Maria¹,

Sanette²

2014

J Res Dent

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Title: The effect of temperature on linear dimensional stability of elastomers.Objectives: Sometimes, dental impressions need to be transported to distant laboratories.It has been reported that the temperature in a vehicle can reach up to 66C when the outdoor temperature is 38C. These temperatures may be reached during South African summers. The objective of this in vitro study was to investigate the effect of temperature and time on the dimensional stability of two elastomeric impression materials.Methodology: Specimens consisted of impressions made of an ISO-specified test-block featuring a pattern of grooves. Materials used were polyether (Impregum Penta) and polyvinylsiloxane (Affinis Precious regular body). Using an SLR camera and standardized technique, the specimens were photographed at 2 different temperatures (21°C and 66°C) and 3 time intervals (30min, 8hrs and 14 days). This resulted in a total of 12 groups (n=10) to be compared. Digital images of the impressions were calibrated and measured using digital analyzing software. These distances were used to evaluate the mean % dimensional change (%DC) for each group. VEPAC module of Statistica 10 was used for the statistical analysis. To analyze exactly where the differences lied, a Fisher LSD correction was applied to correct for multiple pair wise comparisons.Results: Comparing polyether with silicone, there was no difference in the mean %DC for specimens kept at 21°C for 8hrs (polyether=0.364; silicone=0.237). Neither was there a difference between polyether and silicone when heated to 66°C, cooled off, and measured vi after 8hrs (polyether=0.306; silicone=0.297) or after 14 days (polyether=-0.272; silicone=-0.093).For both polyether and silicone, the mean %DC of the groups exposed to 66°C, cooled off and measured after 8hrs (polyether=0.306; silicone=0.297) differed significantly when compared to the group measured after 14 days (polyether=-0.2723; silicone=-0.092) (P<0.0001 and P=0.0029 resp).For both polyether and silicone, the mean %DC of the groups exposed to 66°C, cooled off and measured after 8hrs (polyether=0.306; silicone=0.297) did not differ when compared to the 21°C (polyether=0.364; silicone=0.237). Conclusions:Within limitations of this study, both materials were heat-sensitive. It is recommended that materials return to 21°C before casting. Despite statistical differences, all results were within ISO specifications of maximum 1.5%DC. Dimensional stability: the ability of a material to retain its size and form over time. vii KEYWORDS

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An evaluation of the time-dependent dimensional stability of eleven elastomeric impression materials

Cited by 67 publications

References 13 publications

Dimensional Accuracy and Stability of Silicone Putty Wash Impression Technique with Different Thickness of Light Body Material

Dimensional Accuracy and Stability of Silicone Putty Wash Impression Technique with Different Thickness of Light Body Material

Dimensional stability of polyvinyl siloxane impression material reproducing the sulcular area

The effect of temperature on linear dimensional stability of elastomers

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