Özet:

Fixed dental prostheses that is still popular today is metal-porcelain restoration due to its strength and affordable price and indicated more to the cases that require strength and longevity. One of the important procedure in making porcelain metal restorations is dental preparation. Rough surface preparation especially finishing lines can cause the adaptation of the restoration to the tooth thatis reduced and cause the formation of gaps on the tooth surface and restoration. Restoration with an ill fitting causes marginal microleakage and risk of secondary caries, thus causing failure in making metal-porcelain restorations. The smooth surface of the gingival margin has an important role in maintaining the accuracy at the clinical and laboratory stages. A smooth surface with good finishing line contours can help in getting good clinical impression. At the laboratory stage, it allows porcelain lift-off from the dye and eliminates unsupported tooth structure, which can rupture from the dye causing disruption during fixing, as well as marginal gaps. Smooth finishing line can increase surface wettability when cementing to avoid the formation of cracks, margin leakage, and dissolved cement which can cause caries and restoration failure. Ideally, after preparation, the surface of the preparation results should be smoothed. Surface finishing of preparation can be done with rotary or ultrasonic instruments. The purpose of this research was to determine the effect of the use of finishing instruments: fine diamond bur, tungsten carbide finishing bur, whitestone bur and UDTs finishing kit on the surface roughness of the finishing line and marginal adaptation in metal-porcelain restoration and the relationship between surface roughness of the finishing line using the instrument finishing to marginal adaptation to metal-porcelain restorations. This research type is an experimental laboratory. Overall a total of 40 samples are divided into 2 groups for surface roughness (20 samples) and marginal adaptation (20 samples). Each group was divided into four treatment groups which were prepared using coarse diamond bur followed by finishing with fine diamond bur, tungsten carbide, dura whitestone, UDTs finishing kit. The surface roughness measurement finishing line using the Mitutoyo Surftest Profilometer SJ-310 Series Handheld Roughness Tester, Japan. Measurements were done 3 times at the marked surface points on the sample. The average of the 3 measurements was calculated in µm. The stylus runs 1mm from the external finishing line. Measurement of marginal gap on the metal-porcelain crown is using a stereomicroscope (Zeiss Stereo Discovery, V12, Germany). Four reference lines were made on the tooth, the lines on the tooth wasmid-mesial proximal, mid-distal proximal, mid-palatal, and mid-buccal, with each measurement on the line was done 3 times so that the total measurement in 1 sample was 12 times. Measurement of marginal adaptation with a 12.0x magnification stereomicroscope using a computer with the Axiovision Rail software. 4.8. The results of univariate analysis found that the greatest surface roughness of finishing lines was using a fine diamond bur at 2.32 , followed by whitestone 2.26 , tungsten carbide 1.72 and the smallest using UDTs with an average at 1.47 .Based on the ANOVA test results, the value of p = 0.001 * (p <0.05) can be concluded that there is a significant influence of the finishing instrument on the surface roughness of the finishing line. The results of univariate analysis found that the greatest average marginal adaptation is using a fine diamond that is equal to 20.60 , then followed by whitestone instrument 16.91 , tungsten carbide 13.39 and the smallest using UDTs, with an average of 6,39 . Based on the ANOVA test results, it is seen that the value of p = 0.001 * (p <0.05), it can be concluded that there is a significant influence of finishing instruments on the marginal adaptation of metal-porcelain restoration. Spearman Correlation Test to determine the strength of the relationship between surface roughness of the finishing line and the marginal adaptation of the metal-porcelain restoration based on the finishing instrument, by looking at the correlation value (r). All instruments were positive for the direction of the strength of the roughness of the surface finishing line and the marginal adaptation of the metal-porcelain restoration based on the finishing instrument, meaning that the greater of surface roughness value, the absolute marginal discrepancy value would also be greater (marginal adaptation metalporcelain restoration isbad), however significant was the whitestone and fine diamond instruments whose strength was very strong (r = 0.9, p value = <0.05). The research can be concluded that fine diamond which is often used in daily clinical life turned out to produce the highest roughness compared to finishing tungsten carbide, whitestone and UDTs finishing kit. UDTs bur from ultrasonic instruments produce the smallest surfaceroughness finishing line and the best marginal adaptation to restoration (smallest marginal gap) compared to rotary instruments (fine diamond bur, tungsten carbide finishing, and whitestone). UDTs finishing kits are appropriate for daily clinical use especially for sub gingival case preparation because they can produce the smallest surface roughness value and marginal gaps. The ultrasonic movements do not injure the periodontium tissue.

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