What is recurrent decay around a dental restoration?
Recurrent (secondary) decay is a new cavity that starts in natural tooth at the margin where a filling, inlay, onlay or crown meets the tooth. The restoration itself cannot decay, but plaque that collects along the junction can, and it is one of the most common reasons a restoration is replaced.
Why margins are vulnerable
The junction traps plaque; gaps or worn edges let bacteria in; the gum line and the spaces between teeth are hard to clean. The same risk factors that caused the first cavity continue unless addressed (NIDCR).
How it is found
Visual and tactile examination, bitewing x-rays on a risk-based schedule (ADA), and sometimes light-based aids. A dark line at a margin is not always decay: staining and old material can look similar; a soft, progressing lesion is the concern, and the examination tells them apart.
What changes the risk
Decay risk overall, the restoration's age and size, margins between teeth or below the gum, dry mouth, diet frequency and grinding that opens margins. The Institute for Quality and Efficiency in Health Care describes decay as a process of mineral loss driven by plaque acids (IQWiG).
What is done
| Finding | Usual approach |
|---|---|
| Stain only; margin closed | Monitor |
| Small marginal lesion; rest of restoration sound | Repair that part |
| Decay under the restoration | Remove and restore; sometimes onlay or crown if walls are thin |
| Decay reaching the nerve | Root canal treatment and restoration |
The FDA notes sound restorations do not need replacing (FDA).
Prevention
Fluoride toothpaste; cleaning between teeth daily with attention to restored teeth; fewer sugar exposures; managing dry mouth; reporting a catch, rough edge or sensitivity early.
Next step: Request a consultation or call (805) 565-5111. A request is not a confirmed appointment; the office confirms times during its listed hours (Monday to Thursday, 8 am to 5 pm, plus select Fridays).
Recurrent-decay explainer
In words: the restoration is a stone in a wall; recurrent decay is the mortar crumbling around it.
| Sign | What to do |
|---|---|
| Dark line at the edge | Mention; may be stain |
| Floss catches or shreds | Mention |
| Sweet or cold sensitivity at one restored tooth | Book a visit |
| Food packing | Book a visit |
| Piece of tooth or filling breaks away | Call |
Guides are general education; an examination is needed for individual advice.
Sources
- Oral Hygiene — National Institute of Dental and Craniofacial Research
- Oral Health Topics: X-Rays/Radiographs (updated Mar 26, 2026) — American Dental Association
- Overview: Tooth decay (InformedHealth.org, updated Sep 2023) — Institute for Quality and Efficiency in Health Care (IQWiG)
- Information for Patients About Dental Amalgam Fillings — U.S. Food and Drug Administration
Sources were current when this guide was last updated.
Educational content, not a diagnosis. Please contact the studio to discuss your own situation.