Clear Aligner Glossary: Treatment Terms and What They Mean

An attachment is a small, tooth-colored composite bump bonded to the tooth surface so that the clear aligner can grip the tooth better and apply movements such as rotation and extrusion. Which teeth receive attachments is determined in the digital plan, and they are bonded in the clinic with the help of a template. When treatment is complete, they are removed without damaging the enamel and the tooth is polished.

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Bite ramps are small bumps added to the area of the aligner that sits against the inner surfaces of the upper front teeth in deep bite cases. The lower front teeth contact these ramps, which separates the back teeth from each other; this makes it easier to extrude the back teeth and intrude the front teeth. They are added by the dentist in the digital plan.

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A bracket is a small metal or ceramic piece bonded to the surface of each tooth in fixed orthodontic treatment (braces), through which the archwire passes. The wire applies force to the teeth through the brackets. Brackets are not used in clear aligner treatment; instead, the aligner and, when needed, attachments transmit the force. A comparison of the two methods is provided on the relevant page.

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Bruxism is the unconscious clenching or grinding of the teeth, usually during sleep. It can cause tooth wear and jaw joint complaints. In patients with bruxism, clear aligners may wear out faster; this should be reported to the dentist. The night guard used for bruxism is a protective appliance that does not move the teeth and is different from a clear aligner.

A button is a small metal or composite knob bonded to a tooth that allows an elastic (rubber band) to be attached. In clear aligner treatment, it is used when elastics are needed to correct the jaw relationship; the elastic is attached either via a cutout in the aligner (precision cut) or via a button that sits outside the aligner edge. It is removed when treatment is complete.

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A cephalometric X-ray is a standardized side-view radiograph of the skull and jaws. On this film, the orthodontist measures the position of the jaws relative to each other and to the cranial base, the inclination of the teeth and the direction of growth. It is used to distinguish whether a bite problem is of dental or skeletal origin; in clear aligner planning, it is requested together with a panoramic X-ray when needed.

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A check-up appointment is a visit during clear aligner treatment in which the dentist evaluates whether the teeth are progressing according to the digital plan, checks aligner fit and attachments, and hands over the next aligners. It usually takes place every 6–10 weeks, less often than with braces. The frequency varies depending on the case and the dentist's plan.

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A chewie is a small, soft silicone roll that you bite on for a few minutes after putting in a clear aligner. The biting motion helps the aligner seat fully on the teeth and helps close any gaps between the teeth and the aligner. It is especially recommended in the first days of switching to a new aligner and whenever the aligner is not seating properly. It is provided by the dentist or the manufacturer.

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Clear aligners is the general term for thin, transparent plastic appliances custom-made to move teeth gradually. A series of aligners is prepared based on a digital scan; each aligner moves the teeth one step further. Because they are removable, they are taken out for eating and brushing and are worn 20–22 hours a day. At our clinic, clear aligner treatment is provided with the Invisalign system.

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ClinCheck is the software in the Invisalign system in which the dentist plans, in three dimensions, the movement of the teeth from their starting position to the target position. The plan includes the number of aligners, attachment positions, IPR amounts and the sequence of movements. The dentist can modify the plan and approves it. The animation shown to the patient on screen is a projection; the actual result is monitored through check-ups during treatment.

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A compliance indicator is a small marker on the aligner, found in some clear aligner series made especially for teens, whose color fades depending on how long the aligner has been in the mouth. The dentist and the family can use this marker to monitor whether the aligner is being worn enough. It helps patients meet the daily goal of 20–22 hours of wear; it is not available in every system.

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A crossbite is when one or more upper teeth sit inside rather than outside the lower teeth when biting; it can occur in the front or side areas. Single-tooth crossbites of dental origin can be corrected with clear aligners. For posterior crossbites caused by a narrow jaw, especially in adults, an expansion appliance or surgical support may be needed.

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Crowding is when teeth overlap, rotate or move out of line because there is not enough space in the jaw for them to align properly. It is one of the most common orthodontic problems. Mild and moderate crowding can be addressed with clear aligners, gaining space with IPR if needed; severe crowding may require tooth extraction or braces.

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A deep bite is when the upper front teeth vertically overlap the lower front teeth more than normal; in advanced cases, the lower teeth may touch the roof of the mouth. With clear aligners, intrusion of the front teeth and extrusion of the back teeth can be planned; bite ramps are used for this purpose. The degree of correction is evaluated case by case during the examination.

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A diastema is a gap between two teeth; it is most commonly seen between the upper central incisors. It can result from a thick lip frenulum, small teeth, a missing tooth or habits. Clear aligners are a commonly used method for closing a diastema; retention is important to keep the closed gap from reopening.

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A digital scan is the creation of a three-dimensional digital model of the teeth and gums using a small camera called an intraoral scanner. No traditional impression putty is needed. The resulting model is transferred to the clear aligner planning software and forms the basis for aligner production. iTero is a widely used example of these scanners.

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An elastic is a small orthodontic rubber band worn between the upper and lower jaws; it applies force to correct the jaw relationship and the bite. In clear aligner treatment, it is attached to cutouts in the aligner (precision cuts) or to buttons bonded to the teeth. It is worn for as long as the dentist instructs, usually all day together with the aligner, and replaced every day.

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An Essix retainer is a clear retainer vacuum-formed over a model of the teeth to hold them in place after orthodontic treatment. It looks similar to a clear aligner but does not move the teeth. It is usually worn at night and, because it wears over time, is replaced at regular intervals. Hawley retainers and lingual retainers are other retention options.

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A Hawley retainer is a removable retention appliance made of an acrylic body that rests against the palate and a thin wire that runs across the front of the front teeth. It is used to hold the teeth in place after orthodontic treatment; it is durable and allows minor adjustments. It is more visible than a clear Essix retainer. The dentist decides which type of retainer is appropriate.

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Invisalign is a clear aligner system manufactured by Align Technology and one of the longest-used clear aligner systems in the world. It works in an integrated way with SmartTrack aligner material, ClinCheck planning software and the iTero scanner. Like other systems, it moves teeth with a series of aligners planned by an orthodontist; treatment success depends on case selection and patient compliance.

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IPR (interproximal reduction) is the removal of a very thin layer of enamel (usually 0.2–0.5 mm) with fine abrasive strips or a bur to gain space between teeth. It stays within the thickness of the enamel and, when performed carefully, is considered not to harm the tooth. Whether it is needed and how much is determined in the digital plan; it is not done in every case.

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iTero is an intraoral digital scanner manufactured by Align Technology and widely used in clear aligner planning. It creates a three-dimensional model of the teeth within minutes and does not require impression putty. The scan can be transferred to the planning software of Invisalign and some other systems. It also has a feature for comparing treatment progress with previous scans.

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A lingual retainer is a thin wire bonded to the inner (tongue-side) surfaces of the front teeth after orthodontic treatment. It is not visible from the outside and, because it is not removed, does not depend on patient compliance; it keeps the teeth from shifting back to their old positions. It can make flossing more difficult, and if it breaks, you should see your dentist right away. It is usually used together with a clear retainer.

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Mandibular advancement is an approach that aims to guide a retruded lower jaw forward in adolescents who are still growing. In some clear aligner systems, wing-like features added to the aligners perform this function, so teeth alignment and jaw guidance are carried out at the same time. It is used only in patients who are still growing and in suitable cases.

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Mixed dentition is the period, roughly between ages 6 and 12, when baby teeth and permanent teeth are present in the mouth together. During this period, some clear aligner systems offer series designed specifically for children; the aligners are designed to accommodate falling-out baby teeth and erupting permanent teeth. Whether early treatment is needed is determined during an orthodontic examination.

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A night guard is a hard or soft appliance worn at night to protect the teeth from wear caused by clenching and grinding (bruxism). It does not move the teeth and is not a clear aligner. Bruxism patients using clear aligners cannot wear a night guard together with the aligner; in this case, the dentist monitors aligner wear and suggests a solution if needed.

An open bite is when the front teeth do not touch when the back teeth are closed, leaving a vertical gap between them. It can result from thumb sucking, a tongue-thrusting habit or a skeletal growth pattern. Mild open bites of dental origin can be addressed with clear aligners; skeletal cases may require additional treatment.

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An orthodontist is a dentist who, after dental school, has completed specialty training in orthodontics and specializes in diagnosing and treating irregularities of the teeth and jaws. In Türkiye, orthodontists are referred to by the title 'Uzman Dt.' (specialist dentist) or 'Dr. Dt.' (Doctor of Dentistry, PhD). The Turkish Orthodontic Society and the AAO recommend that the planning and monitoring of clear aligner treatment be carried out under the supervision of a dentist.

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Overbite refers to how much the upper front teeth vertically overlap the lower front teeth when biting; the normal value is a few millimeters. If the overlap is excessive, it is a deep bite; if there is none or it is negative, it is an open bite. In clear aligner planning, the amount of overbite is measured and the target value is set in the digital plan.

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Overjet is the horizontal distance that shows how far the upper front teeth sit in front of the lower front teeth when biting; the normal value is about 2–3 millimeters. Excessive overjet corresponds to a 'protruding teeth' appearance, and negative overjet corresponds to an anterior crossbite. In clear aligner planning, overjet is measured and evaluated to determine whether it is of dental or jaw origin.

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A precision cut is a small hook- or notch-shaped cutout made at the factory on the edge of a clear aligner so that an elastic can be attached. It is used in cases where elastics are planned to correct the jaw relationship; the elastic attaches directly to the aligner without the need to bond a button to the tooth. Its position and shape are determined by the dentist in the digital plan.

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Protruding teeth means the upper front teeth are tilted forward and the horizontal distance in front of the lower teeth (overjet) is increased. It can be of dental origin or result from a lower jaw that sits too far back. Clear aligners can be used in mild and moderate cases of dental origin; skeletal cases may require jaw growth modification during the growth period, or surgery in adults.

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A refinement is an additional set of aligners prepared from a new digital scan when the teeth have not fully reached their target positions at the end of the first aligner series. It may be needed because of insufficient wear time, aligner fit problems or unpredictable tooth movements. Planning one or more additional sets is common in many treatments and is considered part of the treatment.

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Relapse is when teeth that have been corrected with orthodontic treatment gradually shift back toward their original positions. Because the fibers surrounding the teeth and the bone take time to remodel, it is common when a retainer is not worn. Relapse after braces is one of the most common situations in which clear aligners are used. Retention is maintained for life.

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A retainer is an appliance used after orthodontic treatment to hold the teeth in their new positions. Removable types are the clear Essix retainer and the Hawley retainer; the fixed type is the lingual retainer wire. A clear retainer looks similar to a clear aligner but does not move the teeth. The duration of use is determined by the dentist; the general consensus is nighttime wear for life.

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Retention is the period after active orthodontic treatment ends in which a retainer (retention appliance) is used to keep the teeth in their new positions. A removable clear retainer, a Hawley retainer or a fixed lingual wire can be used. The general consensus is full-time wear during the first months, followed by nighttime wear for life. Without retention, relapse can occur.

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A skeletal discrepancy is when a bite problem stems not from the teeth but from differences in the size or position of the upper and lower jawbones; for example, a lower jaw that sits noticeably too far back or forward. Clear aligners do not change the jawbone; in these cases, jaw growth modification during the growth period, or combined treatment with orthognathic surgery in adults, may be required.

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SmartTrack is the name of the multilayer thermoplastic material used in Invisalign aligners. With its more flexible structure, it aims to apply gentle, continuous force to the teeth and help the aligner fit the teeth more closely. Material names are brand-specific; material differences alone do not determine the clinical outcome, and planning and patient compliance matter more.

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The trim line is the cut line that determines where a clear aligner ends at the gum margin. Some systems trim the aligner along a scalloped line that follows the gum margin, while others trim it along a straight line that extends a few millimeters over the gums. The trim line affects the aligner's retention, visibility and gum comfort; it is one of the concrete differences between brands.

A whitening tray is a soft, flexible tray made to hold teeth whitening gel against the teeth; it does not move the teeth. It should not be confused with a clear aligner: orthodontic clear aligners are made of rigid material, produced as a series, and each one is shaped for a different tooth position. Some patients ask their dentist whether they can use their retainer for whitening at the end of treatment; that decision rests with the dentist.