DIMENSIONAL ACCURACY OF PUTTY-WASH ONE-STEP AND TWO-STEP IMPRESSION TECHNIQUE IN FABRICATION OF FIXED PARTIAL DENTURE

BACKGROUND Impression is crucial step in fabrication of fixed partial denture (FPD). The most common impression technique used in fabrication of fixed partial denture (FPD) is putty-wash impression technique, divided into two, which are one step and two step. Dimensional accuracy of one step and two step putty-wash impression technique is still a controversial. The purpose of this study is to find out the impression results difference of dimensional accuracy, inter abutment distance, abutment height, and mesiodistal width among conventional one step technique, modified one step technique with ethyl vinyl acetate spacer, non-spacer two step technique and two step technique with polyethylene spacer. METHODS The design of this study is laboratory experimental. Samples of this study are dye model from master model imprinted with polyvinyl siloxane putty and wash poured with type IV gypsum. The size of the master model is 28,25 mm for inter abutment distance, 8 mm for abutment height and 6,25 mm for mesiodistal width. 40 samples are divided into four groups, which are conventional one step technique group, modified one step technique with ethyl vinyl acetate spacer group, non-spacer two step technique group and two step technique with polyethylene spacer group. The samples are fabricated at Unit Jasa Industri (UJI) Dental FKG USU, the samples are scanned at Laboratorium Simon Dental Medan and measured with 3D Builder software. The samples are measured according to ISO No. 4823 in three dimension which are inter-abutment distance, abutment height and abutment mesiodistal width. RESULTS Mean and standard deviation for group A is -0,216 +/- 0,127%, group B is 0,177 +/- 0,11 %, group C is 0,57 +/- 0,213 %, and group D is -0,375 +/- 0,141%. The mean and standard deviation abutment height for group A is 0,575 +/- 0,271%, group B is 0,013 +/- 0,26%, group C is 0,55 +/- 0,179% and group D is -0,85 +/- 0,444%. The mean and standard deviation mesiodistal width for group A is -1,54 +/- 0,28%, group B is 0,08 +/- 0,173%, group C is -1,168 +/- 0,534 % and group D is -0,72 +/- 0,513 %. CONCLUSIONS Modified one step technique with ethyl vinyl acetate spacer is the most accurate technique in inter-abutment distance, abutment height and mesiodistal width and the accuracy of that technique had significant difference with other techniques.