Pengaruh Focus Power dan Diameter Laser Dioda Terhadap Retensi dan Resistensi Koping Metal Mahkota Klinis Pendek

Abstract

The main problem with crown restoration with short clinical crown conditions is that denture crowns often come off after installation due to lack of preparation height, convergence angle, and axial wall surface area. This is the main cause of mechanical failure in short clinical crowns so that it will affect retention and resistance. Retention is a quality found in dental restorations that functions to resist loose force along the direction of installation. Resistance can be interpreted as a form of preparation that can increase the stability of the restoration and prevent the release of the restoration from loose forces that occur other than the direction of the restoration placement path. One of the factors that can increase the retention and resistance of metal couplings in crown restoration is the surface roughness. The surface treatment procedure using a laser is one of the efforts that can be made to increase the surface roughness of the metal coupling micro. Micro retention in this case is affected by changes in the mechanical properties of Ni-Cr metal after surface treatment. Changes in mechanical properties are characterized by the formation of oxide layers and microposities. Lasers work based on several parameters that can be set and controlled including focus power, diameter, direction and frequency. The parameters of laser focus power and diameter can affect in the formation of the laser beam or focus on the process of forming micropores and oxide layer surfaces in the interfacial area. The purpose of this study is to determine the effect of focus power and diode laser diameter on the surface treatment process on retention and resistance so that crown restoration is not easily detached. The research sample used was a prepared brass rod with dimensions of 3 mm high and 11 mm wide, with a convergence angle of 22 0 . The sample was 30 pieces which were divided into 5 sample groups (n=6) after which surface treament treatment using diode laser was carried out. Mechanical testing using Universal Testing Machine (UTM) with tensile test to see retention in sample groups without surface treatment (0,478 MPa); focus power 2,7 watts and diameter 1 cm (0,806 MPa); focus power 4 watts and diameter 1 cm (0,286 MPa); power 2,7 watts and diameter 3 cm (0,572 MPa) Focus power 4 watts and diameter 3 cm (1;670 MPa); and shear test to see resistance in the sample group without surface treatment (5,13 MPa); focus power 2,7 watts and diameter 1 cm (7,73 MPa); focus power 4 watts and diameter 1 cm (3,92 MPa); focus power 2,7 watts and diameter 3 cm (5,68 MPa) Focus power 4 watts and diameter 3 cm (20,67 MPa). Followed by a roughness test using AFM (Atomic Force Microscope) and FE SEM (Field Emission Scanning Electron Microscopy). Based on the roughness examination using AFM and SEM; the formation of micropores and oxide layer surface in the interfacial area after surface treatment can be seen. The results of the ANOVA test showed that there was a significant influence (p < 0,05) focus power and diameter on the retention and resistance of short clinical crown metal couplings