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Tooth Decay


Tooth Decay or cavities refers to the breakdown of the hard tissues of a tooth structure. In clinical terms, it is known as dental caries. Your tooth has three primary layers, starting from the most sensitive one, pulp, followed by dentin, and finally, the most burdensome outermost layer called enamel. Enamel is the hardest substance in the human body. It can resist several chemicals and mechanical forces. But in the case of poor oral hygiene, it can break down, which leads to tooth decay.


The major factors involved in the initiation of tooth decay are oral bacteria, complex carbohydrates or sugars, and weak tooth structure upon intake of sugary substances, e.g., beverages, bakery products, chocolates, etc., the bacteria residing in plaque that surrounds the tooth ferment these sugars. This process releases acidic substances that reduce the oral cavity’s overall pH. A pH level below 5.5 leads to demineralization of enamel. This weakens the outermost layer of the tooth structure and, if not addressed at an early stage, progresses to dental caries or cavitation of the tooth. The frequency at which these sugary substances are taken also affects the progression of this disease.

Other diseases that make teeth more susceptible to caries include diabetes, severe fluorosis, amelogenesis imperfecta, molar-incisor hypomineralization, and xerostomia.

Stages of Tooth Decay

The progression of tooth decay occurs in three stages. The first stage marks the initial demineralization of enamel. The enamel appears chalky white, opaque, and slightly rough in texture. The second stage leads to further breakdown of enamel that appears as black or brown spots. The third stage involves dentin, which causes hypersensitivity to be hot and cold stimuli if it progresses. The final step involves the innermost pulp layer, which leads to extreme pain, difficulty in chewing, and severe discomfort. In some instances, an abscess might form at the base of the pulp.

Risk Factors and Epidemiology

Primary risk factors for tooth decay include excessive intake of sugars, high intake of sticky substances, poor oral hygiene, dry mouth or medications that decrease salivary flow rate, malaligned teeth, age, inadequate dental fillings, and underlying medical conditions such as diabetes.

Dental caries is the most prevalent disease of tooth structure. It occurs most frequently in children in the US and is the primary cause of early tooth loss. It is also common in older adults as well. Around 29% to 59% of adults over 50 have tooth decay. The prevalence of this disease depends highly upon general awareness among people to maintain their oral hygiene.

Signs and Symptoms

The early symptoms of tooth decay include minor pain and sensitivity to hot and cold substances. In the late stages, you might experience severe pain and discomfort along with hypersensitivity. Bad breath and foul metallic taste might also be present.

Clinically, your dentist determines the stage of tooth decay by visualizing the tooth structure. Black or brown spots are common, especially in the pits of enamel or interdental areas. The affected tooth substance is also softer than the regular tooth structure.


Diagnostic methods for dental caries include visual assessment, clinical assessment, and radiographic assessment. Visual assessment is to observe any noticeable changes in the color or texture of tooth structure. Clinical assessment involves using a mirror and probe to gauge the damage done by caries. Finally, radiological assessment is performed using PA x-rays, bite-wing x-rays, or panoramic x-rays to determine the extent of tooth decays.

Other diagnostic techniques include dental floss, dental tape, caries detecting solution, Digital Fiber-Optic Transillumination, etc.

Differential Diagnosis

Other diseases that present with similar symptoms include molar-incisor hypomineralization, enamel hypoplasia, pigmented lesions, and fluorosis. Diagnosing dental caries based on suitable diagnostic criteria is necessary to avoid mistreatment.


Treatment of tooth decay depends on the stage of the disease at the time of diagnosis. Early-stage tooth decay with minor spots requires brushing with fluoridated toothpaste, fluoride varnishes, or sealants. At stage two or three, drilling the tooth structure is necessary to rid all demineralized substances. After this, your dentist will appropriately restore the tooth with a dental filling. The most commonly done dental fillings are GIC, composite, and amalgam. If the severity has increased up to stage four, you might be suggested a root canal treatment, inlays/ Onlays, or an artificial crown to preserve the remaining tooth structure. In the worst-case scenario, your tooth might have to be extracted and replaced with an artificial tooth.


Oral medication is generally not prescribed in tooth decay except for cases involving the pulp. In patients presenting with extreme pain and swelling, a suitable analgesic such as ibuprofen, diclofenac sodium, or naproxen is prescribed. Broad-spectrum antibiotics such as amoxicillin with clavulanic acid are prescribed in cases of dental abscess formation associated with tooth decay.


If tooth decay is diagnosed early, appropriate measures can effectively treat it. The prognosis of this disease depends on age, dietary habits, and oral hygiene maintenance. Children who consume foods and drinks rich in sugar will have a poorer prognosis than those who limit their sugar intake. Similarly, the forecast will be deficient in adults with underlying medical conditions such as diabetes. If the proper treatment is done to preserve the tooth structure, tooth loss can be avoided.


Several preventive methods can be used to decrease the risk of tooth decay. They include less sugar intake, fluoride toothpaste and varnishes, and proper brushing of teeth twice a day. Flossing in interdental areas reduces the risk of interdental caries. Infants should not be left with milk bottles in their oral cavity for a long time. Sticky foods like caramel toffees, chocolates, or popcorn should be avoided or taken in less frequency. It is always beneficial to get regular dental checkups at least twice a year. This way, you can get an early diagnosis of tooth decay and proper treatment to preserve your natural tooth.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 31, 2023.



Tooth decay - NHS (

Tooth Decay: MedlinePlus

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