Orthodontic appliances are categorized into two major types: movable appliances and fixed appliances according to the way they are fixed in the oral cavity. The structure of movable orthodontic appliances is simple and can be taken off and worn by oneself, which is favorable for the maintenance of oral hygiene, but the control of orthodontic force is not precise enough; fixed orthodontic appliances can effectively control the three-dimensional movement of teeth, but orthodontic brackets and so on are glued to the teeth, so it is not easy for oral hygiene to be maintained. Activity Orthodontic Appliance 1.Mechanical Activity Orthodontic Appliance 2.Functional Activity Orthodontic Appliance 3.Without Bracket Invisible Orthodontic Appliance: without bracket invisible orthodontic appliance has certain indications, not every patient is suitable for use. Fixed orthodontic appliances Fixed orthodontic appliances mainly include brackets, arch wires and buccal tubes. The brackets are bonded to the teeth with adhesive. The archwires are elastic (memory) and are held in place on the brackets by ligature wires or ligature loops. During orthodontic treatment, the archwire connects the brackets on the upper and lower teeth and directs the teeth to move by applying force to the teeth through the brackets. There are many types of fixed orthodontic appliances, such as: square arch braces, Begg braces, Edgewise braces, Alexander braces and straight arch braces. The main difference between these aligners is in the design of the brackets, but all of them can correct the malocclusion. The brackets commonly used in clinic can be divided into metal brackets and ceramic brackets according to different materials; ordinary brackets and self-ligating brackets according to different ligation methods; labial brackets and lingual brackets according to different bonding positions. Nowadays, the mainstream orthodontic appliance in the clinic is straight arch orthodontic appliance, and the following is a brief introduction to the fixed orthodontic appliance commonly used in the clinic. 1.Ordinary metal brackets: Ordinary metal brackets are one of the most traditional and widely used orthodontic appliances in the clinic. Advantages: the lowest price, the most practical, capable of most of the malocclusion correction. Disadvantages: poor aesthetics, oral hygiene care is more difficult. 2, ceramic bracket aligners: ceramic bracket and teeth similar in color, smooth surface. Advantages: better aesthetics, comfort, medium price. It is favored by women who love beauty. Disadvantages: the matching orthodontic arch wire can not be transparent, so close observation can still see a line; colored drinks are easy to stain the ligature ring outside the bracket, so it should be carefully taken care of. Ceramic bracket is divided into full ceramic orthodontic appliances (5-5, 20 ceramics) and ceramic orthodontic appliances (3-3, 12 ceramics) two kinds. 3.Self-locking bracket aligners: Self-locking brackets are specially designed to greatly increase patient comfort as they do not require ligature wires or ligature loops to fix the archwires. Characteristics: the bracket is easy to clean, and the oral hygiene is relatively good; the follow-up interval is longer: 6-8 weeks (4-6 weeks for ordinary bracket); the friction between self-locking bracket and archwire is lower, so the treatment course is relatively shorter than that of ordinary bracket. 4, ceramic self-locking bracket aligner: the combination of ceramic and self-locking bracket is a kind of expensive bracket in the current bracket. 5, lingual side aligner: lingual side invisible orthodontic technology is to transfer the bracket from the lip side to the tongue side, and it can be completely invisible in the front view. Advantages: full invisible aligner, the best aesthetic effect. Disadvantages: easy to injure the tongue; technical operation is difficult; chair-side operation time is long; the price is the most expensive. In the face of a wide variety of orthodontic appliances with different prices and origins, patients are often at a loss as to what to choose, and how to choose a pair of orthodontic appliances that really suits them? Generally speaking, patients can consider according to their own economic conditions, occupation, material of bracket, aesthetics, comfort, length of follow-up interval, length of orthodontic treatment time, maintenance of oral hygiene during treatment, and whether orthodontic appliances are convenient to use. Expensive braces may not necessarily be suitable for you. It is beneficial to listen to your doctor’s advice.