Electrical conductance for the detection of early tooth decay

Dentists often aim to identify tooth decay that has already advanced to a level that needs a filling. If dentists were able to find tooth decay when it has only affected the outer layer of the tooth (enamel) then it is possible to stop the decay from spreading any further and prevent the need for fillings. It is also important to avoid a false‐positive result, when treatment may be provided when caries is absent. This is one of a series of reviews on diagnostic tests for dental caries, we also have reviews on imaging modalities, transillumination, fluorescence devices and tests to detect root caries.

The aim of this Cochrane Review was to find out how accurate electrical conductance devices (non‐invasive devices that send an electrical current to the surface of the tooth) are for detecting and diagnosing early tooth decay as part of the dental ‘check‐up’ for children and adults who visit their general dentist. Researchers in Cochrane included seven studies published between 1997 and 2018 to answer this question.

Dental imaging methods for the detection of early tooth decay

Dentists often aim to identify tooth decay that has already advanced to a level which needs a filling. If dentists were able to find tooth decay when it has only affected the outer layer of the tooth (enamel) then it is possible to stop the decay from spreading any further and prevent the need for fillings. It is also important to avoid a false-positive result, when treatment may be given when caries is absent.

This Cochrane Review aimed to find out how accurate X-ray images and other types of dental imaging are for detecting early tooth decay as part of the dental ‘check-up’ for children and adults who visit their general dentist. Researchers in Cochrane included 77 studies published between 1986 and 2018 to answer this question.

Are antibiotics an effective way to prevent infection following tooth removal?

Teeth that are affected by decay or gum disease or painful wisdom teeth are often removed by dentists. Tooth extraction is a surgical procedure that leaves a wound in the mouth that can become infected. Infection can lead to swelling, pain, development of pus, fever, as well as ‘dry socket’. Dry socket is where the tooth socket is not filled by a blood clot, and there is severe pain and bad odour. These complications are unpleasant for patients and may cause difficulty with chewing, speaking, and teeth cleaning, and may even result in days off work or study. Treatment of infection is generally simple and involves drainage of the infection from the wound and patients receiving antibiotics.

Antibiotics work by killing the bacteria that cause infections, or by slowing their growth. However, some infections clear up by themselves. Taking antibiotics unnecessarily may stop them working effectively in future. This ‘antimicrobial resistance’ is a growing problem throughout the world. Antibiotics may also cause unwanted effects such as diarrhoea and nausea. Some patients may be allergic to antibiotics, and antibiotics may not mix well with other medicines. Dentists frequently give patients antibiotics at the time of the extraction as a precaution in order to prevent infection occurring in the first place. This may be unnecessary and may lead to unwanted effects.

Training opportunities: systematic reviews and related topics

The COVID-19 pandemic has meant that face-to-face training in systematic review methodology has been largely postponed.

However, there are some opportunities to get involved online!

Cochrane has put together a suite of interactive and online learning opportunities. Follow the links to find out more!

Light‐based tests for the detection and diagnosis of early tooth decay

Dentists often aim to identify tooth decay that has already advanced to a level which needs a filling. If dentists were able to find tooth decay when it has only affected the outer layer of the tooth (enamel) then it is possible to stop the decay from spreading any further and prevent the need for fillings. It is also important to avoid a false‐positive result, when treatment may be provided when caries is absent.

How effective are oral hygiene measures for preventing pneumonia in critically ill people on ventilators?

Ventilator‐associated pneumonia (VAP) is a lung infection. It develops in patients who are on artificial breathing machines (ventilators) in hospitals for more than 48 hours. Often, these patients are very ill – they may have had a heart attack or stroke, a serious accident, or major surgery. They may be unable to breathe on their own because they are unconscious or sedated while they receive treatment. Ventilators supply patients with oxygen through a tube placed in the mouth or nose, or through a hole in the front of the neck. If germs enter through the tube and get into the patient’s lungs, this can lead to VAP. VAP is a potentially very serious complication in patients who are already very ill. It can cause worsening health and increases patients’ risk of dying.

Keeping a patient’s mouth clean and free of disease could help to prevent VAP. Oral hygiene care includes mouthwash, antiseptics, using swabs to clean the mouth, toothbrushing and tools like suction devices, which suck away fluid from the mouth. These measures can be used on their own or combined.

How accurate are fluorescence devices for detecting and diagnosing early tooth decay?

Dentist holding caries detector with fluorescent light for checking the teeth.

Dentists often aim to identify tooth decay that has already advanced to a level which needs a filling. If dentists were able to find tooth decay when it has only affected the outer layer of the tooth then it is possible to stop the decay from spreading any further and prevent the need for fillings. It is also important to avoid a false-positive result, when treatment may be provided when caries is absent.

Diagnostic tools for detecting root caries: uncertain evidence

Root caries (tooth decay on the root of a tooth) is a well-recognised disease, that is on the increase as populations grow older and keep more of their natural teeth into later life. Like coronal caries (tooth decay on the crown of the tooth), root caries can be associated with pain, discomfort, and tooth loss, which can contribute to poorer oral health-related quality of life in the elderly. Detecting caries earlier can mean invasive treatment is needed, where more tooth tissue can be preserved. It could also mean less cost to the patient and to healthcare services.

What are the benefits and risks of using antibiotics as well as cleaning by a dental care professional to treat gum disease?

Gum disease is a common condition in which the gums become swollen, sore, or infected. It is caused by bacteria that accumulate on gums and teeth. Diseased gums may bleed when people brush their teeth and may cause bad breath. If gum disease is not treated, teeth can become loose and eventually fall out. This can affect a person’s ability to chew and speak. It can also make people feel self‐conscious about their appearance. Dental‐care professionals can clean teeth and gums to remove excess bacteria from the mouth. They use special instruments – typically, an ultrasound scraper followed by specialised hand‐held instruments – to scrape bacteria from the teeth and stop these from affecting the gums.

Antibiotics (medicines that kill bacteria) taken by mouth (orally) can be used alongside professional cleaning, to remove bacteria from the area between the teeth and gums. However, there are potential risks associated with antibiotics, such as allergic reactions and antibiotic resistance (changes in bacteria after exposure to antibiotics, that allow the bacteria to survive future antibiotic treatment).

Sealants or fluoride varnishes: which treatment is better for preventing decay in the permanent back teeth of children and adolescents?

Tooth decay is when a small hole develops in a tooth. This happens because bacteria that live in the mouth feed on sugar in the food we eat. As they feed, the bacteria produce acid that attacks teeth. If teeth are not cleaned regularly after eating, or if someone consumes a lot of sugary foods and drinks, the repeated acid attacks can create holes in the hard outer surface of the teeth. If untreated, these holes can deepen and damage the layer of tooth underneath the surface (dentine). Many people around the world develop tooth decay at some point in their life. In most adolescents and children over the age of six years, decay damages the biting surfaces of the permanent teeth at the back of the mouth.

To prevent decay, dentists can apply a dental sealant, or fluoride varnish, directly onto the back teeth. A dental sealant is a coating made from an adhesive material such as resin or glass ionomer, which the dentists applies once to teeth. It seals off the grooves in teeth that tend to collect food, and protects them from the acid. By comparison, a fluoride varnish is a sticky paste that contains high levels of fluoride; fluoride is a mineral naturally present in teeth that protects them from damage. Fluoride varnishes need to be applied to teeth by the dentist two to four times a year.