Dental caries, or tooth decay, is a progressive process where the hard structure of the tooth is broken down by acids produced by oral bacteria. Whether a rotten tooth hurts depends on how far the decay has advanced. While the earliest stages are painless, once decay penetrates the protective outer shell, it can lead to severe sensations, including sharp sensitivity or a deep, throbbing ache. Recognizing this progression is key to seeking timely treatment.
Understanding the Stages of Tooth Decay
Tooth decay begins with the demineralization of the enamel, the hardest substance in the human body. This initial stage appears as a chalky white spot, representing the loss of minerals due to acid exposure. Since no physical hole has formed, the process can often be reversed with proper oral hygiene and fluoride application.
If acid attacks continue unchecked, the decay progresses into the enamel, leading to a small cavity that may appear brown or dark. Once the enamel is breached, the decay accelerates as it reaches the underlying dentin, which is softer and more porous. Dentin contains microscopic tubules that connect to the pulp, creating a pathway for external stimuli.
This progression into the dentin is often when symptoms begin, including a visible hole, noticeable discoloration, or bad breath. As the decay deepens toward the center, it eventually invades the pulp, which houses the tooth’s nerves and blood vessels. This final stage leads to a severe bacterial infection and inflammation, which can result in the formation of an abscess at the root tip.
Why Decay Causes Pain and Other Sensations
Pain results directly from decay reaching the sensitive layers of the tooth structure. When decay erodes the enamel and exposes the dentin, microscopic tubules open to the mouth environment. This exposure causes transient sensitivity, especially when consuming hot, cold, or sweet items, as stimuli affect the fluid within the tubules, leading to nerve irritation.
A more intense pain occurs when decay reaches the pulp, leading to pulpitis, or inflammation. Since the pulp is enclosed within the rigid walls of the tooth, inflammation causes pressure to build up on the nerves and blood vessels. This pressure results in the characteristic deep, sustained, and often throbbing toothache that can radiate into the jaw or face.
If inflammation is left untreated, the pulp tissue can die, and the bacterial infection can spread beyond the root tip, forming a dental abscess. An abscess is a pocket of pus that causes severe, localized pain, swelling of the gums or face, and sometimes a fever. This advanced stage is concerning because the infection can spread to other areas of the body if not immediately treated.
Primary Factors Leading to Dental Caries
The development of dental caries requires four main factors:
- A susceptible tooth surface
- Specific bacteria
- Fermentable carbohydrates
- Time
The primary culprits are acid-producing bacteria, notably Streptococcus mutans, which colonize the tooth surface in a sticky film called plaque. These bacteria adhere strongly to the enamel, forming a robust biofilm.
The process is fueled by consuming fermentable carbohydrates, such as sucrose, glucose, and fructose, found in sugary foods and drinks. Streptococcus mutans metabolizes these sugars to produce lactic acid. This acid lowers the pH level within the plaque biofilm below the threshold of 5.5, which causes the minerals in the tooth enamel to dissolve.
The frequency and duration of exposure to these acidic conditions are significant contributing factors. Each time fermentable carbohydrates are consumed, the environment becomes acidic, increasing the time the tooth is subjected to demineralization. Lifestyle factors, such as inconsistent oral hygiene and a genetic predisposition to weaker enamel, further influence susceptibility to this destructive cycle.
Necessary Interventions and Treatment Options
The treatment for dental decay is determined by the specific stage of disease progression. In the earliest stage of demineralization, the process can often be reversed with non-restorative treatments like professional fluoride applications. This treatment helps remineralize the enamel, strengthening the tooth structure against future acid attacks.
Once a physical cavity has formed, the standard intervention is a dental filling, or restoration. The dentist removes the decayed material and fills the space with a restorative substance, such as composite resin or amalgam, to seal the area. Larger cavities or teeth with significant structural loss may require a crown, a custom-fitted cap that covers and protects the remaining tooth structure.
If the decay has advanced to the pulp and caused irreversible inflammation or infection, a root canal is typically necessary. This treatment involves removing the infected pulp tissue, thoroughly cleaning and disinfecting the inner root canals, and then sealing the space. In cases of severe infection, extensive structural loss, or failed root canals, the final intervention may be a tooth extraction to prevent infection spread.