COMPARATIVE INVESTIGATION OF MECHANICAL PROPERTIES OF BALL ATTACHMENT MANUFACTURED FROM DIFFERENT ALLOYS AND SURFACE IMPROVEMENT PROCESSES

The retaining system commonly used in overdenture prostheses is the ball attachments, which are deformed over time, which can affect the retention and stability of the prosthesis. The aim of this study is to research the physical properties of the ball attachments which are made of different alloys and used for surface treatment. In our study, ball attachments produced from different alloys (Grade 4, Grade 5, Grade 23, CoCr) and applied various surface treatments (no surface treatment, anodisation, micro-arc oxidation coating) were used. Samples were prepared in the laboratory environment and exposed to the thermal cycle, which corresponds to a 5-year aging process, by means of chewing simulators. The changes in the surface properties of the ball attachments as a result of the aging process were evaluted with scanning electron microscopy (SEM-EDX) and X-ray diffractometry (XRD). Considering that the deformation in the matrix and the patrix would affect the retention resistance, tensile bond strength test was applied in a universal test device to measure this resistance. Values were recorded in Newtons and Megapascals. In order to detect the wear on the patrix, weight measurements were made on precision scales. Values were recorded in milligrams (mg). The data were analysed using the SPSS programme. As a result, loss of retention and wear were observed on all ball attachments and matrix. Retention and weight loss were seen the most in the titanium grade 4 group and the least in the CoCr group. No significant difference was found between the other groups.