Most orthodontic miniscrews stay firm until their work is finished. A meta-analysis by Papageorgiou and colleagues (American Journal of Orthodontics and Dentofacial Orthopedics, 2012) put the overall failure rate at about 13.5 percent, or roughly one screw in seven or eight, and a screw that loosens can usually be taken out and, if still needed, replaced nearby. These small titanium screws, also called temporary anchorage devices or TADs, give braces and aligners a fixed point in bone to work from, and they are removed once the tooth movement is complete.
Teeth need something to push against
Every force used to move a tooth has an equal and opposite reaction. In traditional orthodontics, the reaction is taken up by other teeth, usually the back molars. That works up to a point, but the anchor teeth tend to drift too, which can use up space the orthodontist wanted to keep or move teeth that were already in the right place. Managing that unwanted movement is called anchorage.
A miniscrew sidesteps the problem because it sits in bone rather than on a tooth, so it does not drift in response to the force. Think of rowing away from a jetty rather than pushing off another boat. With a stable anchor, the treating clinician can move the teeth that need moving and leave the others alone.
The jobs miniscrews are used for
One common use is closing the space left after teeth are removed for crowding, while holding the back teeth exactly where they are so the front teeth are pulled back further. Miniscrews can also help push over-erupted teeth back into the gum, for example a molar that has grown down into the space of a missing lower tooth, or upright a tooth that has tipped. In some cases they let the whole row of upper teeth be moved backwards to correct a bite.
Before miniscrews became widely used, some of these movements relied on appliances worn outside the mouth. Our guide to orthodontic headgear explains how that older approach works, and why a miniscrew inside the mouth can now provide similar anchorage in many cases. Miniscrews work alongside fixed braces and clear aligners, both of which are covered in our article on how to straighten crooked teeth.
Screws in the palate can also widen the upper jaw
In older teenagers and adults, a conventional expander attached only to the teeth often tips the teeth outwards instead of widening the bone, because the suture in the middle of the palate and the joins around the upper jaw become more resistant with growth. Miniscrew-assisted rapid palatal expansion, or MARPE, uses two to four miniscrews in the roof of the mouth to deliver the expansion force to the bone. In a meta-analysis of 14 studies, Siddhisaributr and colleagues (Korean Journal of Orthodontics, 2022) found that about 56 percent of the widening measured at the back of the palate came from the bone itself, about 24 percent from bending of the tooth-bearing bone, and about 20 percent from tipping of the teeth. A separate review reported expansion succeeding in about 92 percent of late adolescents and adults, although the included studies were rated as very low quality evidence (Kapetanović and colleagues, European Journal of Orthodontics, 2021).
Lumi Dental places MARPE appliances for suitable adults. Our article on adult palatal expansion with MARPE covers who may be suitable and how the assessment works.
Placement takes minutes and is done under local anaesthetic
The gum over the chosen site is numbed, and the screw is turned through the gum into the bone, usually between the roots of two teeth or in the palate. The site is chosen from X-rays and a clinical examination so the screw avoids tooth roots, and many placements need no cut in the gum. Most people describe pressure rather than pain during placement.
Afterwards the gum can feel tender for a day or two, and the screw head may rub the cheek or tongue until the soft tissues get used to it. Over-the-counter pain relief is usually enough. The screw can often be used straight away or after a short wait, depending on the plan.
Why a miniscrew sometimes loosens
Unlike a dental implant, a miniscrew is not designed to fuse with the bone. It is held mainly by its thread, which is what makes it easy to remove later but also means it can work loose. The clearest risk factor is the screw touching a tooth root, which raised the risk of failure several-fold in a systematic review by Mohammed and colleagues (Progress in Orthodontics, 2018). Gum inflammation around the screw, thin or less dense bone and heavy early forces are also thought to play a part, although the evidence for most factors is limited. Screws placed in the midline of the palate had the lowest reported failure rates in that review. A loose screw is rarely harmful. It is usually removed, the area left to heal, and a new one placed in a slightly different position if it is still needed.
Keeping the area clean does the most good
Gum inflammation around the screw is one of the factors patients can influence. Brushing gently around the head of the screw twice a day with a soft brush, and using a mouth rinse if your dentist or orthodontist suggests one, helps keep the tissue healthy. Try not to play with the screw with your tongue or fingers. If it feels loose, or the gum around it becomes sore, red or swollen, contact the treating clinic rather than waiting for the next appointment.
Removal is usually quicker than placement
A miniscrew stays only as long as it is needed, often several months. Taking it out is usually a matter of unscrewing it, and many people need no anaesthetic, though a little numbing gel or a small injection can be used. The tiny hole in the gum generally closes within days, and the bone fills in beneath it.
What people ask about TADs
Is a miniscrew the same as a dental implant?
No. Both are made of titanium, but a dental implant is larger, is designed to bond with the bone, and permanently replaces a missing tooth. A miniscrew is much smaller, is held mainly by its thread, and is removed when treatment is finished.
Will other people see it?
Usually not. Most screws sit well back between the teeth or in the roof of the mouth, and are hidden by the lips and cheeks when talking and smiling.
Does everyone having braces or aligners need one?
No. Many orthodontic plans manage anchorage well without miniscrews. They are used when a particular tooth movement would be difficult or less predictable without a fixed anchor.
If you are considering orthodontic treatment and would like to know whether miniscrews might be part of the plan, our team in Melrose Park can talk it through with you. You can start with our general dentistry page or see our current offers.
