{"id":6793,"date":"2026-06-07T09:58:39","date_gmt":"2026-06-07T00:58:39","guid":{"rendered":"https:\/\/sachi-dent.com\/6793\/"},"modified":"2026-07-23T14:44:58","modified_gmt":"2026-07-23T05:44:58","slug":"a-tooth-i-thought-was-treated-has-a-cavity-again-causes-and-prevention-of-secondary-caries-recurrent-cavities","status":"publish","type":"post","link":"https:\/\/sachi-dent.com\/en\/6793\/","title":{"rendered":"“A tooth I thought was treated has a cavity again?” Causes and prevention of secondary caries (recurrent cavities)"},"content":{"rendered":"

Hello, this is Shiba Koen \/ Mita SACHI Dental Clinic. 🦷<\/p>\n

Have you ever experienced a tooth that was supposed to have finished treatment in the past developing a cavity again without you noticing?
\nThis is called “secondary caries” (recurrent cavities), and it refers to a condition where a cavity develops again around the fillings or crowns that were previously placed during treatment. In fact, it is said that many cavity treatments for adults are due to these secondary caries.<\/p>\n

Why do treated teeth develop cavities again?<\/p>\n

\n1. Deterioration of fillings and crowns over time<\/h2>\n

The inside of the mouth is a harsh environment where cold and hot things enter and biting force is constantly applied. When fillings and crowns gradually deteriorate over years of use, microscopic gaps can form between them and your own teeth. When bacteria enter those gaps, cavities tend to progress from the inside. In particular, silver teeth and resin (plastic) used in insurance-covered treatments are prone to deterioration and deformation over the years due to the characteristics of the materials, and plaque also tends to adhere to them easily.<\/p>\n

2. Missed spots during self-care<\/h2>\n

The boundary (step) between the filling or crown and the tooth is a point where dirt inevitably tends to accumulate. If plaque remains, cavity-causing bacteria produce acid, which dissolves the tooth again.<\/p>\n

3. Decrease in saliva, or teeth grinding and clenching<\/h2>\n

Saliva has an important self-cleaning action that washes away dirt in the mouth and protects the teeth. When the amount of saliva secretion decreases due to stress, aging, or the effects of medication, the risk of cavities increases. Additionally, the strong load from unconscious teeth grinding or clenching can cause damage to fillings or create gaps.<\/p>\n

Be careful of these signs<\/h2>\n

* Sensitivity to cold or sweet things
\n* Pain or discomfort when biting
\n* Fillings or crowns have come off, or feel like they are floating
\n* The teeth around the filling have turned blackish<\/p>\n

A characteristic of early secondary caries is that subjective symptoms such as pain are unlikely to appear. Caution is required because they have often progressed by the time you notice them.<\/p>\n

To protect your precious teeth from secondary caries<\/p>\n