Introduction to Retention Bridge Accuracy

The research on the accuracy of the retention bridge mainly includes the adaptability of the retention body, the error of the long line distance of the near and far edge of the fixed bridge, the distance and angle of the deviation of the central axis of each retention body, etc., in the 1950s, in order to improve the accuracy of the fixed bridge , The whole casting method is gradually used clinically to replace the traditional welding method. However, due to the casting shrinkage effect of non-precious metals, as the span increases, the accuracy of the entire cast bridge becomes worse. Ziebert et al. believe that the accuracy of the whole cast bridge beyond three units cannot be guaranteed.

The working principle of laser welding is that the energy of laser welding is high-density monochromatic light and electromagnetic energy, which acts on a tiny area (such as weldment joints) by focusing and bombarding the metal to melt it. Then it cools and solidifies together. After the laser beam is focused, the spot diameter can be as small as 0.01mm, the energy density can be as high as 109w/cm2, and the heat is concentrated.

Laser welding has an immeasurable impact in all aspects, most of which are used in industry, medical treatment, and processing.

The effect of laser welding on the accuracy of multi-unit fixed bridges. The research on the accuracy of retention bridges mainly includes the adaptability of the retention body, the error of the long line distance of the fixed bridge near and far edge bridge, and the central axis of each retention body. The distance and angle of deviation, etc.

The research on the accuracy of the retention bridge mainly includes the adaptability of the retention body, the near-distal edge of the fixed bridge In the 1950s, in order to improve the accuracy of the fixed bridge, the whole casting method was gradually used clinically to replace the traditional welding method. However, due to the casting shrinkage effect of non-precious metals, as the span increases, the accuracy of the entire cast bridge becomes worse. Ziebert et al. believe that the accuracy of the whole cast bridge beyond three units cannot be guaranteed.

The laser welding technology has the advantage of small deformation, so the laser welding method after segmented casting can be used to reduce the impact of the shrinkage of the cast gold. An experiment compared the integral casting method with the laser welding method for a four-unit fixed bridge, and the results proved that the accuracy of the laser welding bridge was significantly greater than that of the integral casting bridge.

In segment casting, attention should also be paid to the selection of investment materials with sufficient expansion, and the correct casting method should be used. Only by ensuring that each single crown retainer is accurately in place, can the entire welded bridge obtain sufficient accuracy. Bruce believes that the span of less than 15.5mm can be accurately cast, so when segmenting, it is generally appropriate to use 1 to 3 single crowns (depending on the size).