Abstract
Objective: Despite the increase of all-ceramic prosthesis in dental practice there is no evidence of the possibility of welding these structures if necessary. The objective of this study was to use CO2 laser (?=10.6µm) as a welding agent to fuse dental polycrystalline alumina ceramic. Methods: Ceramic blocks of pre-sintered alumina were sectioned into 20 bars (10.0 x 1.5 x 1.5mm) and sintered to the final cross?section dimension of 1.2 x 1.2mm. The bars were adapted to an LHPG (Laser Heated Pedestal Growth) system device where the bars could be fixed in pairs and have their ends irradiated with CO2 laser to fusion. The ring-shaped laser beam (300 µm thickness) was directed with the aid of mirrors to reach samples’ ends. The laser was continuously applied (40W nominal power, 5 seconds). After welding, the samples were analyzed in stereomicroscope and SEM. A diffraction analysis was carried out with one sample. Results: The ceramic bars were successfully fused, but some of them showed some shape distortion in the fusion zone. The aspect of the fused alumina differed in color and translucency from the original sintered material. SEM evidenced the presence of porosity and voids in the center of the fusion zone. X-ray diffraction pointed to a reduction in crystallite size by two to four times in the welded region of samples. Conclusions: This study points to CO2 laser as a possible welding agent to polycrystalline alumina dental ceramic. Porosity observed in the molten zone gives cause for concern regarding weld resistance.
Highlights
F or many years, metallic alloys have been used in dental prosthesis framework manufacturing with good predictable results [1]
The bars were adapted to a device used for ceramic fiber growth, in a process known as LHPG (Laser Heated Pedestal Growth)
The CO2 laser in the studied parameters was able to weld the alumina bars and the LHPG device proved to be a useful tool throughout this preliminary study
Summary
F or many years, metallic alloys have been used in dental prosthesis framework manufacturing with good predictable results [1]. In addition to their mechanical strength, metallic structures present the possibility of being welded, if a misfit or failure occurs [2]. There are several welding processes for metallic framework in dentistry, with all types of welding presenting their own advantages and disadvantages [3]. Among these processes, laser is widely chosen for its advantages, such as its high penetration, lower piece distortion, and celerity [3,4]. The process disadvantages include the residual stress that affects the final resistance of the welded structures and the presence of porosity in the joint area [3,5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
