teeth, and fewer adjustments are required than with traditional braces. Gold-plated stainless steel braces are often employed for patients allergic to nickel (a basic and important component of stainless steel), but may also be chosen because some people simply prefer the look of gold over the traditional silver-coloured braces. Lingual braces are a cosmetic alternative in which custom-made braces are bonded to the back of the teeth making them externally invisible. Titanium braces resemble stainless-steel braces but are lighter and just as strong. People with allergies to the nickel in steel often choose titanium braces, but they are more expensive than stainless steel braces. Customized orthodontic treatment systems combine high-technology including 3-D imaging, treatment planning software and a robot to custom bend the wire. Customized systems such as this offer faster treatment times and more efficient results. Progressive, clear removable aligners may be used to gradually move teeth into their final positions. Aligners are generally not used for complex orthodontic cases, such as when extractions, jaw surgery, or palate expansion are necessary. Fitting procedure Orthodontic services may be provided by any licensed dentist trained in orthodontics. In North America most orthodontic treatment is done by orthodontists, who are dentists in diagnosis and treatment of malocclusions—malalignments of the teeth, jaws, or both. A dentist must complete 2–3 years of additional post-doctoral training to earn a specialty certificate in orthodontics. There are many general practitioners who also provide orthodontic services. The first step is to determine whether braces are suitable for the patient. The doctor consults with the patient and inspects the teeth visually. If braces are appropriate, a records appointment is set up where X-rays, molds, and impressions are made. These records are analyzed to determine the problems and the proper course of action. The use of digital models is rapidly increasing in the orthodontic industry. Digital treatment starts with the creation of a three-dimensional digital model of the patient's arches. This model is produced by laser-scanning plaster models created using dental impressions. Computer-automated treatment simulation has the ability to automatically separate the gums and teeth from one another and can handle malocclusions well; this software enables clinicians to ensure, in a virtual setting, that the selected treatment will produce the optimal outcome, with minimal user input. Typical treatment times vary from six months to two and a half years depending on the complexity and types of problems. Orthognathic surgery may