Pengaruh Konsentrasi Berdasarkan Waktu Pengetsaan Asam Fluorida terhadap Shear Bond Strength Bahan Repair Porcelain pada Fraktur Kohesif Restorasi Porcelain Fused to Metal

Abstract

Porcelain fused to metal (PFM) restorations are one of the most commonly used restorations for fixed dentures because they have high strength, long durability, good biocompatibility, and satisfactory esthetics. These restorations are easily chipped and fracture due to their brittle nature. Porcelain fracture is the second biggest failure after caries. Repairing porcelain directly in the mouth using composite resin repair is the choice because it is cost-effective, has a short processing time, and is easy to apply. The direct repair process requires mechanical bonding to produce high adhesive strength between porcelain and resin. The use of hydrofluoric acid (HF) is the "gold standard" as a surface treatment agent to achieve high adhesive strength. Hydrofluoric acid has drawbacks because its toxic nature will make it dangerous when it comes into contact with oral tissue. Strict protocols are required to pay attention to its application, and prolonged use in the mouth is avoided as much as possible. High or low HF concentrations used can affect the application time for producing adhesive strength. The adhesive strength is affected by surface roughness, which is caused by the formation of pores resulting from the dissolved glass matrix. The resulting pores allow the resin material to penetrate the porcelain surface. This will produce optimal bond strength between porcelain and composite resin materials. High adhesive strength is needed because the PFM recovery results can withstand the functional strength of masticatory pressure in the oral cavity. The purpose of this study was to determine the effect of concentrations of 9%, 9.5%, and 10% hydrofluoric acid for 30; 60; 90; 120; and 150 seconds on the adhesive strength of the porcelain repair material in the cohesive fracture of the restoration of porcelain fused to metal. The research samples were made in the form of feldspathic porcelain with a cylindrical shape with a diameter of 7 mm and a thickness of 3 mm. As many as 64 samples were carried out. The sample group was divided into 4 groups, 1 control group and 3 groups based on the application of HF at different concentrations. In the 3 treatment groups with HF etching concentrations of 9, 9.5, and 10%, each was divided into 5 groups based on the etching time of 30; 60; 90; 120; and 150 seconds. The etching patterns can be analyzed using a Scanning Electron Microscope (SEM) and an Atomic Force Microscope (AFM) on each representative sample. Measurement of shear bond strength values was carried out using a universal testing machine. Differences in the effect of hydrofluoric acid concentration based on etching time on the shear bond strength of porcelain repair materials in cohesive fracture of PFM restorations was analyzed by using the normality distribution of data test (Univariant) and one-way ANOVA test. After that, samples that had been tested for shear bond strength were evaluated using a stereomicroscope to see the type of failure. The results showed that there was a significant difference in the concentration of HF 9, 9.5 and 10% for 30 seconds on the adhesive strength of repair porcelain resin composite material on PFM cohesive fracture, the highest adhesive strength was obtained at a concentration of 9.5% (10.276 + 0.047 MPa) and the lowest HF 10% (7.378 + 0.023 MPa), with 75% cohesive failure type and 25% mixture. At concentrations of HF 9, 9.5 and 10% for 60 seconds there was a significant difference in the adhesive strength of the repair porcelain resin composite material on cohesive fracture of PFM, the highest adhesive strength was obtained at a concentration of 9.5% (11.990 + 0.076 MPa) and the lowest was HF 10 % (6.231 + 0.120 MPa), with a failure type of 75% cohesive and 25% mixed. At HF concentrations of 9, 9.5 and 10% for 90 seconds there was a significant difference in the adhesive strength of the repair porcelain resin composite material on cohesive fracture of PFM, the highest adhesive strength was obtained at a concentration of 9.5% (9.479 + 0.461 MPa) and the lowest at HF 10 % (5.553 + 0.061 MPa), with a cohesive failure type of 67.75% and a mixture of 31.25%. At HF concentrations of 9, 9.5 and 10% for 120 seconds there was a significant difference in the adhesive strength of the repair porcelain resin composite material on cohesive fracture of PFM, the highest adhesive strength was obtained at a concentration of 9.5% (10.321 + 0.156 MPa) and the lowest at HF 10 % (5.359 + 0.070 MPa), with a cohesive failure type of 50% and 50% mixture. At HF concentrations of 9, 9.5 and 10% for 150 seconds there was a significant difference in the adhesive strength of the repair porcelain resin composite material on the cohesive fracture of PFM, the highest adhesive strength was obtained at a concentration of 9.5% (10.683 + 0.418 MPa) and the lowest at HF 10 % (5.093 + 0.151 MPa), with a cohesive failure type of 50% and 50% mixture. The conclusion of this research is that the best concentration of hydrofluoric acid is to obtain optimal bond strength values between porcelain and repair material at 9.5% HF with the shortest application time of 60 seconds.