Clinical Effect Evaluation Of Different Impression Techniques On Fixed Prosthesis

Objective: To compare the difference about cervical accuracy of impressions with theindividual teeth tray, agar and silicon rubber impression technique. To evaluate thefeasibility of the individual teeth tray in clinical treatMethods: The experiment was carried out on35patients who came to hospital fromDecember2012to January2014. The method of impression technique was takenrandomly according to the order: conventional tray joint agar alginate impressionmaterial (Group A), conventional tray joint silicone rubber (Group B), individual teethtray silicone joint rubber joint (Group C).Firstly, we excluded some patients who hadpoor oral hygiene, tooth mobility, gingivitis, periodontitis, etc. Then the abutment wasprepared by common method which with135oand1mm shoulder in the dental cervixand2o~5oincisal convergence angle. Meanwhile, the shoulders were0.5mm under thegingival margin. Obtained the impressions under the condition without gingivalretraction technique. Finally, grading all the data according to the criterion of thecervical accuracy, and Kruskal-Wallis test was used to compare the cervical accuracyamong the three test groupsResults: Using SPSS-19.0Kruskal-Wallis rank sum test to compare the data obtained。In ɑ=0.05significance level, among the A, B, C three groups have significantdifference statistically (p <0.05).It can be considered that three different impressiontechniques have significant difference in the cervical accuracy. Thus it requires further multiple comparisons. In ɑ=0.05significance level, There is no significant differencebetween group A and group B (P>0.05), while there is statistically significantdifference between group C and group A (P <0.05).Conclusions: The impression technique with individual teeth tray is beter than agaralginate and silicone rubber impression technique. Individual teeth tray impressiontechnique can copy the shoulder and the tissue under the shoulder accurately.