Your dentist has just told you that you need a filling. Or maybe you’ve been putting off a dental visit because you suspect you might need one and you’re not sure what to expect.
Either way — you probably have questions.
What type of filling is right for you? What exactly happens during the procedure? Will it hurt? How much will it cost? How long will it last? And what do you need to do (or avoid) afterward?
This guide answers every one of those questions — clearly, practically, and without the vague reassurances that leave you more anxious than informed.
Here’s the first thing worth knowing: a filling is one of the most common and most straightforward dental procedures performed. It’s also one of the most important — because getting a cavity filled promptly protects the remaining healthy tooth structure from progressive decay that becomes dramatically more expensive and invasive to treat later.
Let’s get into everything you need to know.
What Is a Dental Filling?
A dental filling is a restorative procedure that repairs a tooth damaged by decay, fracture, or wear — restoring its function, shape, and structural integrity.
When tooth decay creates a cavity — a physical hole in the enamel or dentin — the decayed tissue must be removed and the space filled with a restorative material. Without this, the cavity continues to grow, bacteria colonize the exposed dentin, and decay progressively deepens toward the pulp.
A filling does three things:
- Removes all decayed tissue — stopping active decay
- Seals the space — preventing bacterial recolonization
- Restores tooth structure — allowing normal function
Fillings are also used to repair chipped or cracked teeth, replace old deteriorating fillings, and address tooth surface wear from grinding or acid erosion.
When Do You Need a Tooth Filling?
Not every cavity requires an immediate filling — early enamel demineralization (white spot lesions) can sometimes be reversed with remineralization protocols. But once enamel has physically broken down into a structural cavity, a filling is necessary.
Signs you likely need a filling:
- 🦷 Your dentist has confirmed a cavity on examination or X-ray
- 🦷 You notice a visible hole, pit, or dark spot in a tooth
- 🦷 You have new sensitivity to cold, sweet, or hot stimuli
- 🦷 Food consistently gets stuck between specific teeth
- 🦷 A tooth feels rough or sticky when you run your tongue across it
- 🦷 You have a cracked or chipped tooth causing discomfort
- 🦷 An existing filling is cracked, lost, or deteriorating
Signs you may need more than a filling:
- 🔴 Spontaneous, throbbing toothache — may indicate pulp involvement requiring root canal
- 🔴 Significant facial swelling or fever alongside tooth pain — dental abscess requiring urgent care
- 🔴 Severe tooth structure loss — may require a crown rather than a filling
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Types of Dental Fillings — Complete Comparison
Choosing the right filling material involves balancing durability, aesthetics, cost, and clinical suitability. Here’s everything you need to know about each option.
1. Composite Resin — Tooth-Colored Fillings
The most commonly placed filling type in modern dentistry.
Composite resin is a tooth-colored material made from a mixture of plastic resin and fine glass particles. It bonds directly to the tooth surface using an adhesive system and is cured (hardened) with a blue LED light.
Advantages:
- ✅ Matches natural tooth color — virtually invisible
- ✅ Bonds directly to tooth structure — requires less drilling than amalgam
- ✅ Versatile — used on front and back teeth, chips, and small fractures
- ✅ No mercury content
- ✅ Repairable — damaged areas can be repaired without replacing the whole filling
Disadvantages:
- ❌ Less durable than amalgam under heavy chewing forces
- ❌ Can stain over time from coffee, tea, and wine
- ❌ Takes longer to place than amalgam
- ❌ Higher cost than amalgam in many settings
Lifespan: 5–10 years on average, potentially longer with good oral hygiene and dietary habits
Best for: Front teeth, visible areas, small to medium cavities in back teeth, patients prioritizing aesthetics
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2. Amalgam — Silver Fillings
Dental amalgam is a time-tested alloy containing approximately 50% mercury combined with silver, tin, and copper. It has been used in dentistry for over 150 years and has an extensive safety record.
Advantages:
- ✅ Extremely durable — withstands heavy chewing forces
- ✅ Faster to place than composite resin
- ✅ Lower cost than most alternatives
- ✅ Proven 150+ year track record
- ✅ Self-sealing properties develop over time
Disadvantages:
- ❌ Silver color — highly visible, particularly in front teeth
- ❌ Requires more drilling than composite — removes more healthy tooth structure
- ❌ Contains mercury — though extensive research confirms safety at dental concentrations
- ❌ Being phased out in many countries due to environmental and mercury concerns
- ❌ Can cause minor tooth discoloration (grey tinge) in surrounding enamel
Lifespan: 10–15 years, often longer
Best for: Large cavities in back molars where aesthetics are less critical, patients requiring maximum durability, lower-cost treatment settings
⚠️ Note on mercury safety: The American Dental Association and the World Health Organization have both confirmed that dental amalgam is safe for most patients at concentrations used in fillings. The mercury in amalgam is in a stable alloy form — not the methylmercury form associated with environmental toxicity.
3. Ceramic / Porcelain Fillings (Inlays and Onlays)
Ceramic restorations are fabricated in a dental laboratory or milled chairside using CAD/CAM technology. They’re custom-made to fit the prepared cavity precisely and are cemented into place.
Advantages:
- ✅ Excellent aesthetics — closest match to natural tooth color and translucency
- ✅ Highly durable — porcelain withstands chewing forces well
- ✅ Stain-resistant — maintains appearance long-term
- ✅ Biocompatible — no metal or mercury
- ✅ Preserves more tooth structure than crowns
Disadvantages:
- ❌ Highest cost of filling options
- ❌ Typically requires two appointments (lab fabrication) or specialized chairside technology
- ❌ More brittle than metal — can fracture under extreme forces
- ❌ Not easily repaired if damaged
Lifespan: 10–20 years with good care
Best for: Larger cavities in visible teeth, patients prioritizing longevity and aesthetics, replacing old amalgam fillings
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4. Gold Fillings (Inlays and Onlays)
Gold restorations are the most durable filling option available — and the most expensive. Custom-fabricated in a laboratory and cemented into the prepared tooth.
Advantages:
- ✅ Exceptional durability — gold is extraordinarily resistant to wear and fracture
- ✅ Biocompatible — gold is one of the most tissue-compatible dental materials
- ✅ Precise fit — laboratory fabrication produces excellent marginal sealing
- ✅ Lifespan of 20+ years is achievable
Disadvantages:
- ❌ Most expensive filling option
- ❌ Requires two appointments
- ❌ Highly visible — gold color is conspicuous in the mouth
- ❌ Conductivity — can occasionally cause sensitivity to temperature
Lifespan: 15–30 years
Best for: Patients prioritizing longevity above all else, those with heavy grinding habits, patients who tolerate or prefer visible gold restorations
5. Glass Ionomer Cement
Glass ionomer is a tooth-colored filling material that chemically bonds to tooth structure and releases fluoride — actively protecting the surrounding tooth from further decay.
Advantages:
- ✅ Releases fluoride — ongoing caries protection
- ✅ Bonds chemically to tooth — no etching required
- ✅ Tooth-colored — acceptable aesthetics
- ✅ Less technique-sensitive than composite resin
- ✅ Good choice for areas near the gumline
Disadvantages:
- ❌ Less durable than composite resin or amalgam
- ❌ More susceptible to wear and fracture
- ❌ Appearance less refined than composite
Lifespan: 3–7 years
Best for: Children’s primary teeth, cavities near or below the gumline, patients at high cavity risk (fluoride release benefit), temporary restorations
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Filling vs Root Canal — Understanding the Difference
This comparison comes up frequently — and understanding it helps contextualize the urgency of getting cavities filled promptly.
A filling is appropriate when:
- Decay is confined to enamel and dentin
- The pulp (nerve) is not involved
- No spontaneous pain — only triggered sensitivity
- The tooth has sufficient remaining structure to support a restoration
A root canal is required when:
- Decay has reached the pulp tissue
- There is spontaneous, throbbing pain — particularly at night
- The tooth has developed an abscess
- Nerve tissue is infected or irreversibly inflamed
The critical message: Every filling that is delayed becomes a more complex procedure. A cavity caught at the enamel stage requires a small filling. Left until dentin involvement, it requires a larger filling. Left until pulp involvement — it requires root canal treatment plus a crown. Left until abscess — it may require extraction.
Getting a filling when your dentist recommends it is always significantly less expensive, less invasive, and less painful than treating the same tooth at a later stage.
The Tooth Filling Procedure — Step by Step
Understanding exactly what happens reduces pre-procedure anxiety significantly. Here is the complete filling process:
Step 1: Anaesthesia
Your dentist applies topical anaesthetic gel to the gum before injecting local anaesthetic into the tissue surrounding the tooth. Within 2–5 minutes, the tooth and surrounding area are fully numb.
You will feel pressure and vibration during the procedure — but not pain. If at any point you feel sharp pain, signal your dentist immediately — additional anaesthetic can be administered.
Step 2: Decay Removal
Using a dental drill (handpiece) or, increasingly, air abrasion technology, the dentist removes all decayed tooth tissue from the cavity. The cavity is explored with a sharp explorer instrument to confirm complete decay removal.
This is the step that produces the drilling sound and vibration most patients associate with dental procedures. The duration varies from under a minute to several minutes depending on cavity size.
Step 3: Cavity Preparation
The prepared cavity is shaped to receive the filling material. For composite resin, this involves minimal shaping — composite bonds to tooth structure directly. For amalgam, the cavity may be given a specific undercut shape to mechanically retain the filling.
The cavity is cleaned, dried, and — for composite — etched with phosphoric acid gel for 15 seconds to prepare the enamel surface for bonding.
Step 4: Liner or Base (If Required)
For deeper cavities close to the pulp, a protective liner or base material may be placed over the deepest portion of the prepared cavity before the filling material — protecting the pulp from temperature sensitivity and chemical irritation.
Step 5: Filling Placement
For composite resin:
- An adhesive bonding agent is applied and light-cured
- Composite resin is applied in thin layers — each layer is shaped and cured with the LED light for 10–20 seconds
- Multiple layers build up the restoration to full depth
For amalgam:
- Amalgam is mixed and condensed into the prepared cavity
- Excess is carved away to match tooth anatomy
- The patient bites down to check the bite — any high spots are adjusted
Step 6: Finishing and Polishing
The completed filling is checked for proper bite alignment — any area that feels high when biting is adjusted. The filling surface is then polished smooth — particularly important for composite resin, where a smooth surface resists staining and plaque accumulation.
Total procedure time: 30–60 minutes for a single tooth. Multiple fillings may be done in the same appointment depending on their complexity and location.
What to Expect After a Filling — Recovery Guide
Immediately After the Procedure
Numbness: Local anaesthetic typically lasts 1–4 hours after the procedure. During this time, avoid chewing on the treated side to prevent accidentally biting your cheek, tongue, or lip. Don’t consume hot drinks until sensation returns.
Sensitivity: Some sensitivity is completely normal for the first few days after a filling — particularly to cold, sweet, and biting pressure. This typically resolves within 1–2 weeks as the tooth settles.
High bite feeling: If the filled tooth feels higher than the surrounding teeth when you bite down, contact your dentist for a quick adjustment. An unadjusted high bite causes ongoing soreness and should be corrected promptly.
First 24–48 Hours
For composite resin fillings: Composite is fully hardened at the time you leave the dental office — you can eat on it as soon as the anaesthetic wears off. Avoid very hard or sticky foods for the first 24 hours.
For amalgam fillings: Wait at least 2 hours before chewing on the side of the amalgam filling, and avoid very hard foods for 24 hours while the amalgam reaches full hardness.
Foods to avoid immediately after any filling:
- ❌ Very hard foods (ice, hard candy, hard crusts) — risk of fracturing a new restoration
- ❌ Very sticky foods (toffee, caramel, gum) — risk of pulling filling loose
- ❌ Extremely hot or cold foods — increases sensitivity discomfort
- ❌ Heavily staining foods in first 48 hours after composite — coffee, red wine, curry (composite is more susceptible to staining while the surface is new)
Good food choices after a filling:
- ✅ Soft foods — yogurt, mashed potato, soup, scrambled eggs
- ✅ Lukewarm temperature foods and drinks
- ✅ Foods that don’t require significant chewing on the affected side
Managing Post-Filling Sensitivity
Some degree of sensitivity after a filling is expected — particularly in deeper cavities where the filling material is closer to the pulp. Here’s how to manage it:
For mild sensitivity:
- Use a sensitivity toothpaste (potassium nitrate or stannous fluoride formulation)
- Avoid extreme temperatures in food and drink for the first week
- Take ibuprofen if needed for discomfort
When to call your dentist:
- 🔴 Sensitivity that is getting significantly worse rather than gradually improving
- 🔴 Severe, spontaneous pain that develops after the filling
- 🔴 The bite still feels high after a few days — this needs adjustment
- 🔴 The filling appears to have cracked or come out
Most post-filling sensitivity resolves within 1–2 weeks. Sensitivity that persists beyond 4 weeks, or that is worsening, should be assessed — occasionally a very deep filling causes pulp inflammation that progresses to need root canal treatment.
How Long Do Fillings Last?
Filling longevity depends on material type, cavity size and location, oral hygiene habits, diet, and whether the patient grinds their teeth.
| Filling Type | Average Lifespan |
|---|---|
| Glass ionomer | 3–7 years |
| Composite resin | 5–10 years |
| Amalgam | 10–15 years |
| Ceramic / porcelain | 10–20 years |
| Gold | 15–30 years |
Factors that shorten filling lifespan:
- Teeth grinding (bruxism) — creates excessive force that cracks or wears fillings
- Poor oral hygiene — secondary decay can develop around filling margins
- Consuming very hard foods regularly
- Large filling size — less remaining tooth structure means less support
- High-acid diet — weakens the bond between composite and tooth
Signs a filling needs replacing:
- Cracking or fracturing of the filling material
- Secondary decay visible at filling margins on X-ray
- Sensitivity or pain that wasn’t previously present
- Filling feels rough or edges are sharp
- Visible gap between filling and tooth
Regular dental check-ups every 6 months are the most reliable way to monitor filling integrity — X-rays detect secondary decay at margins that is invisible on clinical examination.
How Much Does a Tooth Filling Cost?
Filling cost varies significantly by material type, cavity size, geographic location, and practice type.
Typical cost ranges (UK/US general guidance):
| Filling Type | Approximate Cost (UK) | Approximate Cost (US) |
|---|---|---|
| NHS amalgam (UK) | £65.20 (Band 2) | N/A |
| NHS composite (UK) | £65.20 (Band 2) | N/A |
| Private composite | £80–£250 per tooth | $150–$350 per tooth |
| Private amalgam | £60–£150 per tooth | $100–$250 per tooth |
| Ceramic inlay/onlay | £350–£800 per tooth | $500–$1,500 per tooth |
| Gold inlay/onlay | £500–£1,000+ per tooth | $700–$2,500 per tooth |
Factors affecting cost:
- Number of tooth surfaces involved — a “two surface” filling costs more than a “one surface” filling
- Location of tooth — posterior teeth are more complex to access and fill
- Geographic area — urban areas typically command higher fees
- Practice type — specialist practices typically charge more than general practices
- Dental insurance — can significantly reduce out-of-pocket cost
The cost of delay: A cavity requiring a £150 composite filling today may require a £900 root canal and £800 crown if left untreated for 12–18 months. The economics of prompt treatment are compelling.
Common Questions About Fillings — Answered
Can I eat before a filling? Yes — eat normally before your filling appointment. Arriving hungry makes the local anaesthetic feel more intense and the appointment less comfortable. If you’re having sedation, fasting guidelines apply — your dentist will advise.
Will getting a filling hurt? The procedure should not cause pain — local anaesthetic eliminates sharp sensation. You’ll feel pressure and vibration. The injection itself causes brief sharpness that the prior topical gel significantly reduces. Most patients are surprised by how manageable the experience is.
Can I drive after a filling? If you’ve had local anaesthetic only — yes. If you’ve had any form of sedation — no. For local anaesthetic, the numbness doesn’t impair driving ability (though be careful not to accidentally bite your lip).
Do fillings require special aftercare? No complex aftercare required — maintain your normal brushing and flossing routine. Use a sensitivity toothpaste if needed. Avoid very hard, very sticky, and very temperature-extreme foods in the first 24–48 hours. Contact your dentist if the bite feels high or sensitivity worsens rather than improves.
Can a filling fall out? Yes — this can happen, particularly with older fillings. If a filling falls out, call your dentist promptly. In the meantime, the exposed tooth is sensitive and vulnerable to further decay — rinse with salt water and avoid chewing on that side. Temporary filling material from a pharmacy can provide short-term protection until your appointment.
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Conclusion
A tooth filling is not something to fear — it’s one of dentistry’s most routine, most effective, and most important procedures. Getting a cavity filled promptly protects the remaining healthy tooth structure, stops active decay, and prevents the progression to root canal, crown, or extraction.
The type of filling that’s right for you depends on where the cavity is, how large it is, your aesthetic priorities, and your budget. Your dentist is your best advisor on this decision — but this guide gives you the knowledge to have that conversation informed.
Look after your filling with good daily oral hygiene, regular check-ups, and sensible dietary habits — and it will look after you for many years in return.
Already working on keeping future cavities away? Our guides on how to prevent cavities naturally and foods that cause cavities are the perfect next reads for building your complete dental health system.
Frequently Asked Questions
Q: What is a dental filling and when do you need one? A dental filling is a restorative procedure that removes decayed tooth tissue and fills the resulting space with a restorative material — stopping decay progression and restoring tooth function. You need a filling when tooth decay has physically broken down enamel into a structural cavity, when a tooth is chipped or cracked causing discomfort, or when an existing filling is deteriorating. White spot lesions — the earliest stage of decay — may not require immediate filling if caught early enough for remineralization.
Q: What is the best type of dental filling? The best filling type depends on individual factors. Composite resin is the most commonly chosen — tooth-colored, bonds well, and suitable for most cavity sizes. Amalgam offers maximum durability at lower cost, making it appropriate for large back tooth cavities. Ceramic inlays/onlays provide the best combination of aesthetics and longevity for larger restorations. Gold offers exceptional longevity but is visible and expensive. Your dentist will recommend the most appropriate material based on cavity size, location, your bite forces, and your priorities.
Q: How long does it take to get a filling? A single filling typically takes 30–60 minutes from anaesthetic to completion. Multiple factors influence the time: cavity size and depth, location in the mouth, filling material chosen, and whether multiple surfaces are involved. Composite resin fillings take longer than amalgam due to the layering and curing process. Ceramic and gold inlays typically require two appointments as laboratory fabrication is needed between visits.
Q: How long does tooth sensitivity last after a filling? Mild sensitivity to cold, sweet, or bite pressure is normal for 1–2 weeks after a filling, as the tooth settles. This is particularly common in deeper fillings closer to the pulp. Using a sensitivity toothpaste and avoiding temperature extremes helps manage it. Sensitivity that is worsening rather than improving, or that persists beyond 4 weeks, should be reported to your dentist — occasionally a very deep filling causes pulp inflammation requiring further treatment.
Q: Can I prevent needing fillings in the future? Yes — through consistent daily oral hygiene, reducing the frequency of sugar and acid exposure, using fluoride toothpaste and not rinsing after brushing, and attending professional cleanings every 6 months. Dental sealants applied to back molar grooves significantly reduce fissure cavity risk. Catching early demineralization (white spot lesions) at check-ups and applying remineralization protocols can prevent these from progressing to cavities requiring fillings. Our complete guide on preventing cavities naturally covers every evidence-based prevention strategy.