Orthodontic Dictionary

In this section you will find a guide to the language orthodontists use to talk about your braces. We would like you to be better informed about your braces; and we also hope this will help you describe and communicate any brace problems with your orthodontist, his nurse, or his receptionist.

Fixed Braces
Removable and Functional Braces
Retainers
Headgear
Miscellaneous

 

Fixed Braces

Archwire
The archwire is the piece of wire that connects all the brackets together. Archwire technology has revolutionised the practice of orthodontics in the last 15-20 years with the introductions of nickel-titanium archwires which have exceptional shape memory. Stainless steel archwires are still used in the latter part of treatment.

Band
This is a metal ring that fits usually around a back (molar) tooth. Bands have a tube where the archwire is inserted, and a hook for attachment of ligatures or elastics. Upper molar bands may also have headgear tubes to receive the inner arms of the headgear facebow.

Bracket
The bracket is the metal or ceramic button that is attached to the tooth. Each bracket is shaped specifically for each tooth, and has been designed to move the tooth to their ideal position. If you don't look after your brace, brackets can become detached from teeth, and feel loose on the archwire.

Coil Spring
Coil springs are small metal springs that are attached to or over the archwire in order to close or open spaces.

Colours
Colours on a brace are ‘modules’ which are tiny doughnut-shaped rubber rings that are used to hold the archwire onto the brackets. Modules are either clear or come in a variety of colours so that you can customise your brace.

Elastics
Elastics are little rubber bands that are worn between upper and lower braces to help certain tooth movements. They are attached to hooks. It is important to wear elastics as instructed by your orthodontist otherwise your treatment will not progress well, and the quality of the final result will suffer.

Headgear Tube
These are metal tubes with relatively wide apertures attached to molar bands or molar/buccal tubes of a fixed brace; or to clasps of a removable brace. The receive the ends of the inner arms of headgear facebow.

Hooks
These are 2-3 mm long posts that are found on bands, molar tubes, some brackets, and even on some thicker archwires. Hooks are used to attach small elastics or ligatures.

Ligature Wire/Tie Wire
A ligature is a very thin piece of wire that is sometimes used either to tie groups of teeth together (usually in a criss-cross formation); or to tie the archwire onto the brackets.

Lingual Arch
This is a thin arch-shaped metal bar that is connected to bands on lower molar teeth. It fits just on the inside of the teeth and gums so that it does not affect tongue activity. A lingual arch is used to maintain space further back in the lower jaw for straightening crowded front teeth.

Module
Modules are tiny doughnut-shaped rubber rings that are used to hold the archwire onto the brackets. Modules are either clear or come in a variety of colours so that you can customise your brace.

Molar Tube/Buccal Tube
This term is used to describe either a bracket that is glued to the back (molar) teeth; or the tube or aperture attached to a molar band. The end of the archwire goes through the molar tube.

‘O’-Lig
An ‘O’-Lig is a module and a ligature connected to each other. Often, the module part is attached to the hook on a molar band or tube, and the ligature part is tied to hooks on an archwire. They are used mainly to close spaces between teeth.

Power Chain
This is an elastic rubber chain that fits over the archwire and brackets to connect teeth together. Power chain has to be stretched to be fitted, so once fitted, it becomes active to move teeth towards each other and close spaces.

Quadhelix
This is an appliance fitted on the inside of the upper teeth, near the roof of the mouth (palate) which is attached to bands on upper molar teeth. The wires that make up a quadhelix normally incorporate four coils, hence its name. It is designed to produce slow gentle expansion of a narrow upper jaw, usually as part of an upper fixed brace.

Transpalatal Arch
This is a thin metal bar that crosses the back of the roof of the mouth (palate) and connects bands on upper molar teeth. It is used to maintain space further back in the upper jaw for straightening crowded front teeth.

 

Removable and Functional Braces

Acrylic
This is the hard plastic material that the baseplate is made of. It sometimes rubs against the gum, causing discomfort, and may need to be adjusted.

Aligner
This is a clear arch-shaped mouthguard/gumshield-like removable brace made of flexible plastic. Invisalign® or similar braces are called aligners.

Baseplate
This is the plastic part of the brace that covers the gum and has the wire components of the brace attached to it. It sometimes rubs against the gum, causing discomfort, and may need to be adjusted. The brace should be cleaned with your toothbrush and toothpaste to remove food and plaque from the baseplate. The acrylic of the baseplate may be designed to be thicker in places either to stop the back or front teeth biting together; or in the case of functional braces to make the upper and lower removable components fit together in a certain way.

Bow/Labial Bow
A bow is an arch-shaped piece of wire that comes around the front teeth. It is usually the only part of a removable brace that is visible as a thin wire crossing the front teeth. It often has small U-shaped loops near the canines. Labial bows can have many purposes: these include keeping teeth where they are (retention), pushing teeth back, keeping the braced in place, and even straightening slightly irregular teeth where possible.

Clasp
A wire that acts as a clip to affix the brace to the teeth is called a clasp: basically any part of the brace that stops it from falling out. There are many types of clasps but some of the most commonly used are the ‘Adams’ (on the back teeth), the ‘Southend’ (on the front teeth), the ‘ball-ended’ (on the front teeth), and the ‘C-clasp’ (front or back teeth).

Expansion Screw
If your removable or functional brace has one of these, you will find it on a split in the baseplate of the brace. Screws are commonly used to expand a narrow upper arch, or to move a single tooth, or groups of teeth. They need to be activated on a regular basis by the patient (sometimes called ‘tightening’ by patients), usually once or twice a week. You should adjust the screw as instructed and at the correct rate in order for the teeth to move in the desired way.

Headgear Tube
This is a tube soldered to a clasp further back on the removable brace. It is designed to receive the inner arm of a headgear facebow.

Key
This a piece of wire about an inch long and the thickness of a paper clip that looks roughly like a key, and is used to activate and turn the expansion screw.

Retainer
All removable braces are sometimes wrongly called retainers. A retainer is a type of removable brace that is used after active orthodontic treatment to maintain the correction of the bite and alignment of the teeth, so that teeth do not relapse back to their original positions. Retainers must be worn as instructed by your orthodontist to prevent unwanted tooth movement.

Spring
These are made from delicate thin pieces of wire and are used to move teeth. Springs can be distorted easily, and great care should be exercised when inserting a removable brace so that springs are not damaged and that they fit in the correct position. Similar care should also be taken when removing, handling or cleaning a brace.

 

Retainers

Acrylic
This is the hard or soft plastic material that most of or the entire retainer is made of. It is usually clear or pinkish in colour, but it can also be made in a variety of colours. It sometimes rubs against the gum, causing discomfort, and may need to be adjusted.

Baseplate
This is the hard plastic part of some retainers that covers the gum and has the wire components of the retainers attached to it. It is usually clear or pinkish in colour, but it can also be made in a variety of colours to suit your taste. It sometimes rubs against the gum, causing discomfort, and may need to be adjusted. The retainer should be cleaned with your toothbrush and toothpaste to remove food and plaque from the baseplate.

Bonded Retainer
A bonded or fixed retainer is made from a fine piece of special wire that is stuck to the back of the teeth so that it is not visible from the front. It is fixed and cannot be removed. Having taken various factors into consideration, your orthodontist will determine which retainer or combination of retainers is suitable for your teeth.

Bow/Labial Bow
A bow is an arch-shaped piece of wire that comes around the front teeth. It is usually the only part of a retainer that is visible as a thin wire crossing the front teeth. It often has small U-shaped loops near the canines. Labial bows in retainers are designed to keep teeth straight. In some retainers it may be covered by a thin layer of clear acrylic.

Clasp
A wire that acts as a clip to affix the retainer to the teeth is called a clasp: basically any part of the retainer that stops it from falling out. ‘Adams’ clasps are the most commonly used clasps on the back teeth.

Essix Retainer
This is a soft clear plastic retainer which fits over your teeth a little like a mouthguard. It has no wires and is almost invisible. Having taken various factors into consideration, your orthodontist will determine which retainer or combination of retainers is suitable for your teeth.

Fixed Retainer
A fixed or bonded retainer is made from a fine piece of special wire that is stuck to the back of the teeth so that it is not visible from the front. It is fixed and cannot be removed. Having taken various factors into consideration, your orthodontist will determine which retainer or combination of retainers is suitable for your teeth.

Removable Retainer
Removable retainers can be made either from wires and hard plastic (where you only see a thin horizontal wire on the front of your teeth), or from soft clear plastic (which fits over your teeth a little like a mouthguard – often called the ‘Essix’ retainer). Having taken various factors into consideration, your orthodontist will determine which retainer or combination of retainers is suitable for your teeth.

Retainer
Retainers are fixed or removable appliances that maintain and hold the alignment of your teeth and the improvement of your bite after the completion of active orthodontic treatment. They are usually passive and are not designed to move teeth. Even after orthodontic treatment, your teeth can lose their alignment throughout growth and even in adulthood. Retainers are designed to prevent such undesirable changes. If you don’t wear retainers the irregularity of your teeth is likely to relapse to some degree, and it will be very hard to correct again. Wearing retainers exactly as instructed is the best guarantee of keeping your teeth straight for a lifetime.

Headgear

Facebow
The facebow is an apparatus made of thick inflexible wire which connects your brace to the rest of the headgear. Generally, the facebow consists of two metal components which have been attached together. The first component: ‘inner arms’ which go inside the mouth and are shaped like a horseshoe, and the ends of the inner arms fit into headgear tubes on your fixed or removable brace. The inner arms often have U-shaped loops for adjustment, and locking hooks for securing them in place. The second component: ‘outer arms’ which fit outside the mouth close to the cheeks. The outer arms are curved or hooked at the end where the traction modules and the safety strap are attached. Never remove your facebow from the mouth while the rest of the headgear is still attached to it: you must dismantle your headgear part by part.

Headgear
Headgear is a brace that is worn on the head in the evening and at night to move the back teeth further back in order to create extra space; or to stop the back teeth from moving forwards and keep them in their present position, whilst the front teeth are being straightened. If you don’t wear your headgear as instructed, it may mean that your front teeth will be left sticking out at the end of treatment! Headgear also helps you achieve the best possible bite between your upper and lower teeth. Headgear is made up of several components.

Headgear Cap
This is the part of your headgear that fits on the back of your head. It is attached to the facebow via the traction modules. It may be worn on its own, or in combination with a neck-strap.

Neck-strap/Neck-pad
This is the cushioned part of your headgear that fits round the back of your neck. It is attached to the facebow via the traction modules. It may be worn on its own, or in combination with a headgear cap.

Safety Strap
This is a white flexible strip of plastic with holes which is fitted round the back of the neck from one outer arm of the facebow to the other. It is another safety feature of your headgear which prevents the accidental ejection of the facebow from your mouth.
Traction Module/Safety-Release Module
This is the elasticated device that connects the facebow to the headgear cap and/or the neck-strap. Once stretched, it creates forces that pull back on the facebow and ultimately on your brace and your teeth. It has a safety release mechanism so that if it is over-stretched, its components come apart to stop it pulling on the facebow. This is another safety feature of your headgear which prevents the accidental ejection of the facebow from your mouth.

 

Miscellaneous

Appliance
This is the term orthodontists use to describe any orthodontic brace.

Mouthguard
A device that is used to protect the teeth and mouth from injury when participating in sports or physical games. The use of a mouthguard is especially important for orthodontic patients.

Separator
Separators are tiny elastic rings which are fitted between the back teeth. They are usually blue in colour. Separators create very small spaces between the back teeth to enable orthodontic bands to be fitted around the teeth a few days later. With a little space between the teeth, there is no need to force the bands between the teeth, and this can be done much more comfortably and without any pain.

Tightening
This is a term used by orthodontic patients to describe any adjustment of an orthodontic brace. When braces are adjusted your teeth may feel ‘tighter’ and that is why this word is used.

Wax
A clear pliable material used as a cushion to prevent certain components of an orthodontic brace from irritating lips and cheeks, mainly needed during the first few days of treatment.

 

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