Laser welded versus resistance spot welded bone implants: analysis of the thermal increase and strength

Effectiveness of laser welding in cerclage wiring fixation: a biomechanical study

Introduction

Cerclage wiring is a common orthopedic procedure for fracture fixation. However, previous studies reported wiring-related perioperative complications, such as wire loosening or breakage, with an incidence rate of up to 77%. Recently, the use of laser welding on medical implants was introduced to connect biomedical materials. This study used laser technology to weld between wires after conventional cerclage fixation. We hypothesized that the laser welding could significantly increase the biomechanical properties of cerclage wiring fixation.

Materials and methods

Twenty-five wiring models underwent biomechanical tests in five cerclage wiring configurations (five models per group), namely, (1) single loop, (2) single loop with laser welding, (3) double loop, (4) double loop with one-side laser welding, and (5) double loop with two-side laser welding. Characteristics such as load to failure, mode of failure, and wiring failure were compared between groups. The biocompatibility for a 316L stainless steel wire with laser welding was evaluated via an in vitro hemolysis test.

Results

Mean load to failure of the double loop with one-side and two-side laser welding groups were 3,596 ± 346 N and 3,667 ± 240 N, which were significantly higher than for the double-loop group (2,919 ± 717 N) (p = 0.012 and p = 0.044, respectively). Conversely, no significant difference was shown in the comparison of the mean load to failure between the single loop and the single loop with laser-welded cerclage wire (1,251 ± 72 N, 1,352 ± 122 N, and p = 0.12). Untwisted wire and wire breakage were the most common mode of failure. All welding specimens revealed non-hemolytic effects from in vitro hemolysis test.

Conclusion

Laser welding on cerclage wiring significantly increases the biomechanical property of double cerclage wire fixation. However, further biocompatibility tests and clinical studies are still recommended.

Applications of Laser Welding in Dentistry: A State-of-the-Art Review

The dental industry without lasers is inconceivable right now. This captivating technology has outlasted other possible alternative technologies applied in dentistry in the past due to its precision, accuracy, minimal invasive effect as well as faster operating time. Other alternatives such as soldering, resistance (spot) welding, plasma (torch) welding, and single pulse tungsten inert gas welding have their pros and cons; nevertheless, laser welding remains the most suitable option so far for dental application. This paper attempts to give an insight into the laser principle and types of lasers used for dental purposes, types of dental alloys used by the dentist, and effect of laser parameters on prosthesis/implants. It is apparent from the literature review that laser assisted dental welding will continue to grow and will become an unparalleled technology for dental arena.

Fatigue limits of titanium-bar joints made with the laser and the electric resistance welding techniques: microstructural characterization and hardness properties

Fatigue behavior of the titanium bars is of utmost importance for the safe and reliable operation of dental implants and prosthetic constructions based on these implants. To date, however, only few data are available on the fatigue strength of dental prostheses made with electric resistance welding and laser welding techniques. This in-vitro study highlighted that although the joints made with the laser welding approach are credited of a superior tensile strength, joints made with electric resistance welding exhibited double the minimum fatigue strength with respect to the joints made with laser welding (120 vs 60 N).