Inside Dental Technology
May 2011, Volume 2, Issue 5
Published by AEGIS Communications
The Laser Welder Alternative
The Orion Pulse 200i micro pulse-arc welding system supplies the laboratory with an affordable laser-like solution for metal repairs.
Crown-and-bridge repairs can be frustrating and costly for both technicians and laboratories. The demand for fast turnaround and profitability for the laboratory rests on the right tools. In the past, soldering was primarily used for all metal framework repairs. This low-fusing metal solder basically "glued" bridge sections together. Problems with contaminates, strength, and overheating were always issues. Welding, on the other hand, melts parent metal of the cast frame, sometimes with no wire needed, to offer superior fit and strength. Additionally, pulse-arc "tig" welding generates minimal heat and may be used adjacent to porcelain and acrylic.
The new Orion Pulse 200i micro pulse-arc welding system supplies the laboratory with an affordable "laser-like" solution for metal repairs. This versatile tool can be put to use in both crown-and-bridge and removable laboratories with an easy learning curve and virtually no maintenance. Welding applications include titanium bars, bridge repair, holes, margins, adding contacts, clasp repair, and orthodontic applications.
In this case, the Orion Pulse Welder takes the frustration out of a six-unit, noble, high-palladium, warped bridge. First, the bridge should preferably be sectioned away from any margins, if possible. Use cutting disks that start out wide and reduce in thickness to create a gradual "hourglass" type cut. Place the two sections back on the model with joint halves passively touching with a vertical line (Figure 1). Keeping a minimum gap between any joint will help with the success of the weld.
When starting repair, remember welding basics. The first weld shot should be directed in the gingival third of the joint (Figure 2). Alternate weld shots from labial to lingual, understanding that the bridge will pull slightly towards the energy on every ignition. Add appropriate gauge fill wire while welding until gingival and middle thirds are solid, then move toward incisal or occlusal. Always check bridge frame fit while welding. If a slight spring appears, focus the electrode directly under the joint and add more wire until connected (Figure 3). When the bridge joint is strong, the Orion Pulse's rapid-fire setting can be utilized to fill the rest of the joint at about five shots per second (Figure 4).
Changing power settings is fast and easy with Orion's 9-inch color touch screen. For example, to lower power and time for a partial-frame clasp repair, the technician simply needs to drag his finger to the most comfortable setting or select from one of 50 customizable saved settings. Welding a partial-denture frame can be done quickly, with as little as two shots. The technician can weld directly on the model, even within a millimeter of acrylic. The low-heat qualities of pulse-arc welding will reduce acrylic scorching, as compared to laser welding (Figure 5 and Figure 6). Power settings can also be increased in one touch to 200 joules of energy, which can penetrate up to 1.5 mm.
When adding a contact to a full-cast crown, start by using a matching alloy wire (Figure 7). Alloys with higher percentages of palladium or silver blend more successfully with increased levels of gold—50% or higher is suggested. The Orion's pulse-shaping and pulse-agitation features also decrease the chance for micro-cracks in the weld. Be sure to lay the wire flush against the contact to be added, this will ensure that the wire will flow and not "ball up." Again, use either the single-fire or rapid-fire ignition speed settings, and position the electrode right next to the wire. Lay a bead of overlapping welds straight across the contact. If the resulting bead is not adequately smooth, repeat again with no wire across the same line at a 45° angle to push and smooth the metal. Repeat these steps until the desired thickness of the contact is achieved (Figure 8 and Figure 9).
For most laboratories, there will always be repairs in the crown-and-bridge and removable departments. The need for an affordable, fast welding system that takes up little space is necessary. The Orion Pulse 200i pulse-arc and tack welder has been engineered and designed with both the small and large dental laboratories' needs in mind. This affordable, true laser alternative is a technological advancement that can provide solutions for the laboratory's welding needs.
Matthew Hotelling, CDT, is finish and polish supervisor in the crown-and-bridge department at Drake Dental Laboratory in Charlotte, North Carolina.
The manufacturer provided the preceding material. The statements and opinions contained therein are solely those of the manufacturer and not of the editors, publisher, or the Editorial Board of Inside Dental Technology.