Dental caries (tooth decay) is one of the most common oral diseases and is also largely preventable. It develops when dental biofilm repeatedly metabolises fermentable carbohydrates and produces acids, leading to loss of mineral from the tooth. If the process continues, it can cause cavities, pain, infection and eventually tooth loss. Early caries can often be managed conservatively before a filling is required.
What is dental caries and how does it develop?
Caries is a biofilm-mediated, sugar-driven disease of the dental hard tissues. Acid produced by bacteria lowers the pH at the tooth surface and shifts the balance towards demineralisation. When demineralisation repeatedly outweighs remineralisation, a carious lesion develops.
Important factors include:
Cariogenic dental biofilm
Fermentable carbohydrates, especially frequent sugar exposure
Time and frequency of acidic challenges
Tooth and host factors, including saliva and fluoride exposure
Early mineral loss may appear as a white-spot lesion. If the process continues and the surface breaks down, a cavity can form and progress into dentine.
Risk factors for caries
Frequent intake of sugary or retentive foods
Sugar-containing drinks, including soft drinks, energy drinks and juices
Frequent snacking or sipping between meals
Insufficient plaque control
Inadequate fluoride exposure
Dry mouth due to medication, disease, dehydration or other causes
A previous history of active caries
Children and adolescents can be at higher risk during certain stages, but caries can occur at any age, including root caries in older adults.
How does caries damage a tooth?
The process begins with microscopic mineral loss. If it is not arrested:
the lesion can progress through enamel
once dentine is involved, progression may be faster
deep caries can irritate or infect the dental pulp
this can lead to pain, pulpitis, apical infection or abscess formation
severely damaged teeth may eventually become unrestorable
An important point is that early caries often causes no pain, which is why regular risk-based dental assessment is useful.
Modern diagnosis
Depending on the situation, assessment may include:
clinical visual and tactile examination
bitewing radiographs when justified, especially for approximal lesions
photographic or digital scan documentation to monitor change
additional caries-detection aids in selected situations
documentation of caries risk and lesion activity
Early detection supports a minimally invasive approach and, for non-cavitated lesions, may avoid drilling altogether
.
Treatment options
1. Early non-cavitated enamel lesionIf there is no cavity, treatment often focuses on disease control rather than a filling:
fluoride to support remineralisation
fissure sealing where appropriate
improved plaque control
dietary counselling
reducing the frequency of sugar exposure
2. Small cavitated lesions
Minimally invasive restorative treatment may involve:
selective removal of carious tissue according to lesion depth
restoration with composite resin
while preserving as much sound tooth structure as possible
3. Larger defects or structurally weakened teeth
Direct or indirect restorations such as onlays, partial crowns or crowns may be considered depending on remaining tooth structure.
For very deep caries, selective caries removal and pulp-preserving strategies may be appropriate in selected vital teeth.
4. Irreversible pulpal disease or pulpal necrosis
Root-canal treatment may be required if the pulp can no longer recover.
The tooth then needs an appropriate definitive restoration, for example an onlay, partial crown or crown, depending on the remaining structure.
What does the evidence show?
Caries is a dynamic disease process and modern management focuses on controlling the causes as well as restoring damage when necessary.
Systematic-review evidence shows a dose-response relationship between free-sugar exposure and caries; frequency of intake is particularly relevant because repeated exposure prolongs periods of demineralisation.¹
Fluoride is well established for caries prevention and promotes remineralisation while reducing demineralisation when used at appropriate concentrations.²
Bitewing radiographs are useful for detecting approximal lesions that may not be visible clinically, but radiographs are taken according to individual risk and diagnostic need rather than routinely.³
Non-cavitated enamel lesions can often be arrested or remineralised if the disease process is controlled; once a surface is cavitated and cannot be cleaned effectively, restorative treatment is more often required.⁴
Direct composite is a conservative option for many cavities. Larger defects may require an indirect restoration depending on tooth structure, occlusal load and other clinical factors.⁵
Frequently asked questions about caries
Can I have caries without pain?
Yes. Early caries is often symptom-free, and even some deeper lesions can remain painless until the pulp becomes affected.
Can caries be treated without drilling?
Yes, selected early non-cavitated lesions can be managed with fluoride, plaque and diet control, sealing or other micro-invasive methods. Resin infiltration (ICON) is an option for selected lesions.
Are sugar-free drinks better for teeth?
They may reduce caries risk if they contain no fermentable sugar, but many acidic drinks can still contribute to dental erosion.
Is caries contagious?
Caries itself is not a simple contagious infection. Oral bacteria can be shared between people, but disease develops through the interaction of biofilm, diet, saliva, fluoride and behaviour.
How often should I have a dental check-up?
Recall intervals should be based on individual caries and periodontal risk rather than a fixed schedule. Higher-risk patients generally need more frequent review than low-risk patients.
Is fluoride safe?
Yes, fluoride toothpaste and professionally recommended fluoride products are safe and effective when used as directed. Excessive ingestion should be avoided, particularly in young children; as with many substances, the dose matters.Paracelsus famously expressed this general principle of toxicology.
References
Moynihan P, Kelly S. Effect on caries of restricting sugars intake: systematic review. J Dent Res. 2014. PMID: 24323509.
Ten Cate JM. Contemporary perspective on the use of fluoride products in caries prevention. Caries Res. 2013. PMID: 24216583.
Pitts NB, Ekstrand KR. International Caries Detection and Assessment System (ICDAS). Community Dent Oral Epidemiol. 2013. PMID: 23206263.
Featherstone JD. The continuum of dental caries—evidence for a dynamic disease process. J Dent Res. 2004. PMID: 15286120.
Opdam NJ et al. Longevity of direct composite restorations. J Dent Res. 2014. PMID: 24782441.
