From Tooth Decay to Cavity: Understanding the Tipping Point
Tooth decay doesn’t always start with a hole you can see or feel. In fact, decay is a process that happens in stages, and the good news is that the earliest stage is often reversible. So when does decay actually turn into a cavity? Let’s break it down step by step.
The First Signs of Decay
Tooth decay begins when the bacteria in your mouth feed on sugars and release acids. These acids slowly dissolve minerals in the enamel (the hard, protective outer layer of your teeth). At this stage, you might notice a chalky white spot on the tooth. This is called demineralisation, and it’s the earliest sign of decay.
The good news? With fluoride toothpaste, a balanced diet, and your body’s natural defence (saliva), your teeth can often repair themselves. This means you can stop decay in its tracks before it becomes a cavity.
When Enamel Breaks Down
If the acid attacks continue and there’s not enough remineralisation, the enamel becomes weaker and starts to lose its smooth surface. At this point, the protective barrier of the tooth is compromised.
This is the tipping point where decay progresses to a cavity. Once the enamel surface collapses, bacteria can penetrate more deeply, and the damage can no longer be reversed naturally.
What Happens Next?
After the enamel is breached, decay moves quickly into the dentin (the softer layer beneath enamel). Because dentin isn’t as strong, the decay spreads faster and can cause sensitivity to hot, cold, or sweet foods.
If left untreated, the bacteria eventually reach the inner pulp of the tooth, which can cause severe pain and infection, often requiring root canal treatment.
Cavities need urgent attention. Leaving them untreated could mean an extraction.
Spotting the Difference: Decay vs Cavity
Decay (early stage): White spots, no holes, no pain. Still reversible.
Cavity (later stage): Visible hole or brown spot, sensitivity, possible pain. Needs a dentist’s intervention (usually a filling).
How To Prevent Cavities
Brush twice a day with a fluoride toothpaste.
Clean between your teeth with floss or interdental brushes.
Limit how often you snack on sugary foods and drinks.
Visit your dentist regularly to catch problems early.
In Summary
Decay turns into a cavity once the enamel surface actually breaks down. Before that point, you have a chance to reverse the process and keep your tooth healthy. The key is recognising the early signs (like white spots) and taking action before irreversible damage occurs.
Diagram: From Healthy Tooth to Cavity
Healthy Tooth – Strong enamel, no damage.
Early Decay – White spot lesion, minerals lost but surface intact.
Enamel Breakdown – Surface collapses, cavity begins.
Dentin Decay – Decay spreads quickly, tooth sensitivity.
Pulp Involvement – Infection and pain, often needing root canal treatment.
Understanding the journey from decay to cavity empowers you to act early. Remember: cavities can be prevented, but only if decay is caught before the enamel breaks.
