What is the best treatment for children with crowded teeth?

When teeth erupt (come through the gum into the mouth), they may twist, stick out, drop back, or overlap if there is not enough space in the mouth. Losing baby teeth early from tooth decay or trauma can lead to crowded permanent teeth. If crowded teeth affect a child’s self‐esteem or cause pain, damage or chewing problems, the child may be referred to a specialist dentist known as an orthodontist to correct them. Crowded teeth can be prevented or corrected using braces if crowding is mild (less than 4 mm). Removal of some teeth (extraction) may also be needed if crowding is moderate (4 to 8 mm) or severe (more than 8 mm). Fixed braces are used on permanent teeth. Removable braces can be used on baby or permanent teeth, or both. Baby or permanent teeth can be extracted.

Interventions to encourage eruption of eye teeth buried under the gum or growing upwards, without the need for surgery, in children aged 9 to 14 years

Upper permanent canine teeth (commonly known as eye teeth or fang teeth) are positioned in the upper jaw, one on the right and one on the left. In around 1% to 3% of children, they may not erupt (appear from behind the gum and into the mouth) into their correct position. The permanent canine tooth or teeth may grow towards the palate (roof of the mouth) and remain unerupted (buried under the gum). This is known as a palatally displaced canine (PDC). If the permanent canine tooth remains displaced and unerupted, it can damage or change the position of neighbouring teeth, and occasionally it can lead to a cyst.

Management of a PDC can take a long time, involving surgery to uncover the tooth and prolonged orthodontic (brace) treatment to straighten it. Various quicker or easier alternatives have been suggested to encourage the tooth or teeth to erupt. These include extraction (taking out) of the primary (baby) canine, extraction of the primary canine and primary first molar (also called double primary tooth extraction), or using braces to create space in children’s mouths.

Are braces effective for treating crossbite (top back teeth biting down inside the bottom back teeth)?

Posterior crossbite occurs when the top teeth or jaw are narrower than the bottom teeth. It can happen on one side or both sides of the dental arches. This condition may increase the likelihood of dental problems (e.g. tooth wear), abnormal development of the jaws, joint problems, and unbalanced facial appearance. Posterior crossbites affect around 4% and 17% of children and adolescents in Europe and America. 

Different treatment approaches have been proposed, resulting in many different braces being produced. The basic treatment to correct crossbite correction treatment involves using an orthodontic device on the palate (roof of the mouth) to expand the upper jaw by exerting pressure on both sides of the jaw. The devices can be fixed (e.g. quad‐helix, Haas, Hyrax expander) or removable (e.g. expansion plate). Fixed appliances are bonded to the teeth, while removable devices can be taken out of the mouth by patients.

Chemotherapy for mouth and throat cancer

Oral cavity (mouth) and oropharynx (throat) cancers that are detected early are treated primarily with surgery or radiotherapy. These treatments are effective in curing cancer and improving survival. However, with surgery and radiotherapy alone there remains a chance that cancer will recur, which can shorten survival for patients. The addition of chemotherapy to surgery or radiotherapy may help improve survival. 

Chemotherapy treatments are drugs that work by killing rapidly dividing cells such as cancer cells. There are other rapidly dividing cells in our body, such as those on our skin or in our gut. Chemotherapy can affect these healthy cells as well, which is why these treatments can have unpleasant side effects.  

In the treatment of cancer, chemotherapy can be given before surgery or radiotherapy, during radiotherapy or after treatment with surgery or radiotherapy. There are also different types of chemotherapy that can be given either as pills or through the veins (intravenously). These differences in the ways of giving chemotherapy and types of chemotherapy are likely to have different effects on survival. At this time, we do not know which way is best.

This review updates one previously published in 2011.

What are the most accurate tests for screening for cancer of the mouth (oral cancer) and conditions that may lead to oral cancer?

There is a lack of high-certainty evidence to support the use of screening tests for cancer of the mouth and conditions that may lead to mouth cancer in the general population. General dental practitioners and healthcare professionals should be watchful for signs of oral potentially malignant disorders (OPMD) and malignancies whilst performing routine oral examinations in practice for other common oral lesions/conditions.

Upcoming training events for 2022

The following training events in systematic review methodology are available in early 2022. Follow the links to find out more!

What are the benefits and risks of different materials used for retrograde filling in people who need this treatment in order to save a tooth?

Key messages

– Due to a lack of robust evidence, the benefits and risks of different materials used for retrograde filling in root canal therapy are unclear.

– The evidence is not robust enough to determine which material is best to use in retrograde filling.

– We need future studies to strengthen the evidence.

Restoring the back teeth: amalgam versus resin composite fillings

Traditionally, metal fillings made of a silver‐coloured material known as amalgam have been used to treat tooth decay in the back permanent teeth effectively and cheaply. But there have been concerns about the way they look, and concerns about the mercury they contain. The Minamata Convention on Mercury is a global agreement that has promoted a worldwide reduction in the use of mercury (including amalgam fillings) in order to reduce the impact of mercury on the environment. Tooth‐coloured fillings made of a composite resin material have been used as an alternative to amalgam fillings. Initially, they were used only in the front teeth, but as their quality has improved, they have been used in permanent teeth at the back of the mouth.

What are the most accurate tests for finding cancer of the mouth (oral cancer) and conditions that may lead to oral cancer?

Diagnosing mouth cancer involves the surgical removal of a piece of affected tissue (biopsy) which is then sent to a laboratory for examination of the cells using a microscope. This is painful for patients and involves a delay in finding out the results. Persistent abnormal patches or sores in the mouth may represent mouth cancer or oral potentially malignant disorders (OPMDs). OPMDs can sometimes turn into mouth cancer, but if identified early enough patient outcomes can be improved.

Comparing treatments for advanced tooth decay

Tooth decay is very common and can cause pain, eating and speaking difficulties, and self‐consciousness. Teeth are made up of three layers: enamel (hard outer layer), dentine (hard inner layer), and pulp (nerves and blood vessels). Our mouths contain bacteria, which grow in a sticky film over our teeth known as dental plaque. The bacteria live on sugar from our diet and turn it into acid that dissolves the teeth. Saliva can reverse this process, but if there is too much sugar in the diet or bacteria are not removed often enough by toothbrushing then the acids will erode the teeth. This can progress into the dentine, eventually causing a hole in the tooth, which is known as a cavitated carious lesion. If it reaches the pulp, it can cause infection. Cavitated carious lesions can be treated by complete removal of decayed parts of the tooth and placement of a filling. Dentists call this non‐selective carious tissue removal and conventional restoration. Although effective, this risks weakening the tooth or causing problems if the pulp of the tooth is exposed. There are some newer ways of treating the tooth which involve removing less or none of the tooth decay.