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Volume 5 Issue 11 (November, 2017)

Original Articles

Clinical Comparison of Polyvinyl Siloxane Impression for Fixed Partial Dentures using three Different Techniques
Syed Yasir Qadiri, Shabeena Mustafa

Aim: To compare the defects present in impressions between three different techniques using hand mixing elastomers. Materials and methods: Three master impressions were made from each 64 crown preparations with three different techniques totalling to 168 master impressions. PVS impression material, putty (Aquasil ) and light-body (Reprosil) viscosity  combinations were used for every patient with the three techniques i) single stage double mix technique ii) two stage technique with using a spacer and iii) two stage technique without using a spacer. The impressions were rated by two evaluators using Heine binocular magnifying loupe (2.3×) and the results tabulated. The results were presented as percentages. Kappa test was done to compare the obtained results. Results: Out of three techniques the least number of defects were shown by the single stage double mix technique with useable impressions of 96.42%and the two stage technique with using a spacer being the least favorable with usable impression of 86.25%. The two stage technique without using a spacer also had a result of 82.60%. Kappa test was used to compare the individual results. Between technique 1 and 2, there was fair significant agreement between the two methods (p<0.001). But when comparing between techniques 1 and 3 (p= 0.5) and techniques 2 and 3 (p= 0.881), there was insignificant weak agreement signifying that technique 2 impressions were not comparable with technique 1 and 3. Among the defects there was presence of 58 void (60.5%), 26 bubbles (27%) and 12 pulls (12.5%) and absence of any tears. The number of defects located at the margins were 68% and 32% were located at others areas beside the margins. All the pulls were present at the lingual/ palatal aspect of margins while 78% and 56% if voids and bubbles were present at the margins respectively. Conclusion: The single stage double mix technique and two stage technique without using a spacer had a more favorable outcome in comparison to the two stage technique using a spacer using hand mixing technique.
Key words: bubbles, impression material, polyvinyl siloxane, tears, voids.

Corresponding author: Dr. Syed Yasir Qadiri, Professor, College Of Dentistry, Najran University, Najran , KSA
This article may be cited as: Qadiri SY, Mustafa S. Clinical Comparison of Polyvinyl Siloxane Impression for Fixed Partial Dentures using three Different Techniques. J Adv Med Dent Scie Res 2017;5(11):29-32.

 
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