Author/Editor		Zupančič, Rok
Title		Mehanske in korozijske lastnosti lotanih in lasersko varjenih spojev stelitne zlitine
Type		monografija
Place		Ljubljana
Publisher		Univerza v Ljubljani, Medicinska fakulteta
Publication year		2005
Volume		str. 68
Language		slo
Abstract		Background: The longevity of prosthetic restorations is often limited due to the mechanical or corrosive failure in places where parts of metal framework were joined. The conventional joining method is soldering, though recently laser welding became an available and far more practical alternative. Research shows that for most dental alloys laser welded joints have greater tensile strength than soldered ones, demonstrating at the same time lower resistance to cyclic fatigue. The composition of the alloy significantly affects the quality of the laser welded joint. Corrosion resistance of soldered and laser welded joints has so far been compared by microscopical assessment of corrosion defects only. The quantitative comparison of electrochemical properties of different joints is not to be found in the literature. Objective: To determine which joining method offers the best mechanical and corrosion properties to Remanium GM 380 alloy frameworks we compared the properties of soldered joints with two types of laser welded joints. Materials and methods: For tensile testing cylindrical samples of Remanium GM 380 were cast. They were sectioned in the middle, perpendicular to their long axis, and subsequently joined again using different methods. We formed three test groups: - soldering with a Co-Cr solder, - laser welding with a tight joint, - laser welding with the joint in the shape of the letter X. Tensile strength was measured using a Zwick Z 030 testing machine. For the assessment of corrosion properties, we formed the three forementioned test groups, and a controll group of intact cylindrical rods. We used electrochemical impedance spectroscopy and electrochemical potentiodynamic polarization. After mechanical and electrochemical testing, the fracture surfaces and corrosion defects were analized with a scanning electron rnicroscope. Longitudinal sections were analyzed on a metalographic optical microscope.
Descriptors		DENTAL PROSTHESIS DENTAL PROSTHESIS DESIGN DENTAL ALLOYS DENTAL SOLDERING CHROMIUM ALLOYS MATERIALS TESTING TENSILE STRENGTH CORROSION LASERS