Medically reviewed content. Written with guidance from licensed dental practitioners.
Dental fillings are one of the most common procedures in dentistry, but “common” doesn’t mean patients always feel prepared. This guide walks through every stage of the process with real timing data, practical checklists you can actually use, and the specific comparative evidence on materials, sensitivity, and longevity — so you know not just what will happen, but what’s actually normal and what warrants a call to your dentist.
Understanding Dental Fillings
A filling is a restorative material used to repair a tooth damaged by decay or trauma. The main material options are:
- Composite resin — tooth-colored, bonds directly to the tooth, preferred for visible areas
- Amalgam — a durable metal alloy, typically used on back teeth where chewing force is highest
- Gold — highly durable but costly, and requires a lab-fabricated approach (usually two visits)
- Porcelain/ceramic — also lab-fabricated, aesthetic and durable, generally the most expensive option
Your dentist’s recommendation depends on the cavity’s size and location, your bite forces, aesthetic priorities, and cost.
A Note on Sedation Options for Anxious Patients
If dental anxiety is a real barrier for you, it’s worth knowing the range of options beyond simple local anesthetic, since many patients aren’t aware how many exist: nitrous oxide (laughing gas) offers mild, quickly-reversible relaxation and typically allows you to drive yourself home afterward; oral sedation involves taking a prescribed medication before the appointment for a deeper, longer-lasting calming effect, but requires a ride home; and IV sedation offers the deepest level of relaxation for more involved procedures or significant anxiety, also requiring a ride and typically a longer recovery window before you’re fully alert. Discussing this with your dentist ahead of time, rather than in the chair, gives you time to arrange transportation if needed and to ask any questions about the specific option that fits your situation.
Pre-Appointment Checklist
Use this before you go in — a few minutes of preparation genuinely changes how smooth the appointment goes:
- [ ] List current medications and allergies, including over-the-counter supplements — this affects anesthetic choice and any prescribed aftercare
- [ ] Note any history of anesthesia issues — prior numbness that didn’t work well, or reactions to dental injections
- [ ] Eat a normal meal beforehand if local anesthesia is planned, since your mouth will be numb afterward and eating comfortably will be harder for a few hours
- [ ] Ask about sedation options in advance if you have dental anxiety — this is far easier to arrange ahead of time than to request once you’re in the chair
- [ ] Arrange a ride if you’re using anything beyond local anesthetic (nitrous oxide is generally fine to drive after; oral or IV sedation is not)
- [ ] Plan to arrive on time or a few minutes early to complete any paperwork without rushing your actual appointment time
What to Expect During the Procedure, Step by Step
1. Initial Examination
Your dentist examines the tooth and surrounding gum tissue, often taking an X-ray to assess how deep the decay extends and confirm the best treatment approach before starting.
2. Numbing the Area
A topical anesthetic gel is typically applied first to minimize sensation from the needle, followed by an injection of local anesthetic (most commonly lidocaine) near the affected tooth. You may feel a brief pinch, which subsides quickly.
What to actually expect timing-wise: clinical research on lidocaine, the most commonly used dental local anesthetic, shows onset of numbness typically within about one minute of injection, with the numbing effect generally lasting in the range of 2.5 to nearly 3 hours depending on the specific formulation and technique used. This is useful to know concretely — if your lip or cheek is still partially numb an hour or two after your appointment, that’s entirely expected, not a sign anything went wrong.
3. Decay Removal
Once numb, your dentist removes the decayed portion of the tooth with a dental drill, then thoroughly cleans the cavity to eliminate remaining debris and bacteria before placing the filling. Complete removal of decay is essential — any bacteria left behind can continue causing damage underneath a filling that looks fine from the outside.
4. Filling Placement
- Composite resin is applied in layers, with each layer hardened (“cured”) using a special light before the next is added — this layering process is specifically what makes composite placement take longer than amalgam.
- Amalgam is placed in a single step and hardens on its own without curing, which is part of why amalgam appointments are often quicker.
- The filling is then shaped to match your natural tooth contours and polished smooth, with your dentist checking your bite to ensure the filling isn’t sitting too high (more on this below).
5. Post-Procedure Instructions
Your dentist will typically cover avoiding hot, cold, or hard foods for a few hours while you’re still numb (to avoid accidentally biting your cheek or tongue without realizing it), expected sensitivity, and gentle oral hygiene around the area for the first few days.
Day-of-Procedure Checklist
- [ ] Avoid chewing on the numb side until sensation fully returns (typically a few hours)
- [ ] Skip very hot or cold foods and drinks until numbness wears off
- [ ] Take any recommended over-the-counter pain reliever only if needed, following label dosing
- [ ] Brush gently around the treated tooth that evening — don’t skip brushing entirely, just be gentle
- [ ] Avoid very hard or sticky foods on that tooth for the rest of the day
Amalgam vs. Composite: Procedure Differences That Actually Matter
| Factor | Amalgam | Composite |
|---|---|---|
| Procedure steps | Removed, cleaned, placed in one step | Removed, cleaned, placed in layers with light-curing between each |
| Appointment length | Generally shorter | Generally longer, due to layering |
| Moisture control | Less critical | Critical — a rubber dam is often used to keep the site completely dry, since moisture contamination can compromise the bond |
| Typical longevity | Often cited around 10–15 years, sometimes longer | Often cited around 5–10 years, though modern composites are closing this gap |
| Aesthetics | Silver-colored, visible | Tooth-colored, blends with surrounding teeth |
| Best suited for | Back teeth with high chewing load | Visible areas, front teeth, smaller restorations |
A genuinely useful nuance on longevity: the commonly cited “amalgam lasts longer” isn’t as settled as it sounds. A large-scale study analyzing over 6,000 amalgam and 2,000 composite restorations across roughly 800 patients over a 10-year period found failure rates between the two materials were actually similar overall, and by the five-year mark, composites had slightly outperformed amalgam in that particular dataset. Longevity in practice depends heavily on filling size, location, your individual bite forces and habits (like teeth grinding), and oral hygiene — the material itself is only one factor among several.
What Sensitivity Is Actually Normal — With Real Timelines
This is one of the most common sources of unnecessary post-filling anxiety, so it’s worth being specific. Post-operative sensitivity after a filling — to temperature, pressure, or both — is common and, in the large majority of cases, resolves on its own. Clinical research specifically following composite restorations found post-operative hypersensitivity is reversible in most cases, with resolution timelines ranging from about one week up to several months, with most cases subsiding within a few weeks without any intervention needed. A prospective clinical study following posterior composite restorations for 12 months found none of the treated teeth lost pulp vitality, reinforcing that this sensitivity, while sometimes lingering, is generally not a sign of a failing filling.
What to look for — the distinction that actually matters: sensitivity that’s gradually improving, even slowly, over days to weeks is the expected pattern. Sensitivity that’s worsening, that occurs spontaneously without a trigger, or that involves sharp pain when biting down specifically (which can indicate the filling is sitting too high, described next) are the patterns worth flagging to your dentist rather than waiting out.
The “High Filling” Issue — A Specific, Fixable Problem
A filling that sits even very slightly too tall changes how your teeth meet when you bite down, concentrating force unevenly. This is a genuinely common, straightforward issue to identify: it typically causes a sensation of “hitting” that tooth first when you bite, or a dull ache specifically with chewing pressure (rather than temperature) that appears within the first day or two. It’s a quick, five-minute adjustment for your dentist to fix and is one of the more common, easily resolved reasons for a return visit shortly after a filling — worth calling about rather than assuming you simply have to adjust to how it feels.
Post-Filling Watch-List (First Few Weeks)
Keep an eye out for these signs during recovery:
- [ ] Sensitivity that’s improving week over week — expected and normal
- [ ] Sensitivity that’s worsening or hasn’t improved at all after several weeks — worth a call
- [ ] Sharp pain specifically when biting down — possible high filling, easily adjustable
- [ ] Spontaneous pain with no trigger — warrants prompt evaluation
- [ ] Visible crack, chip, or a piece of the filling missing — needs repair before decay can develop underneath
- [ ] A change in how your bite feels overall, beyond just the treated tooth — worth mentioning even if it seems minor
When to Contact Your Dentist
- Persistent pain lasting longer than a few days, or pain that’s getting worse rather than better
- Sensitivity well beyond the typical timeline — if it hasn’t started improving after several weeks
- Visible damage — cracks, chips, or a filling that looks different than when it was placed
- Pain specifically with biting — often a sign of a high filling needing adjustment, not a failed restoration
- Any spontaneous, unprovoked pain, which can indicate the tooth’s nerve is involved and needs prompt attention
Extending Your Filling’s Lifespan
- Good oral hygiene — consistent brushing and flossing reduces the risk of new decay forming at the filling’s margins, which is one of the most common reasons fillings eventually need replacement
- Avoid habitually chewing hard items — ice, hard candy, pen caps — which can crack or dislodge a filling regardless of material
- Address teeth grinding if present — a night guard can meaningfully protect fillings from the elevated mechanical stress grinding places on restorations
- Keep up with routine dental checkups — many filling issues (small cracks, early marginal decay) are caught on a routine exam well before they become symptomatic
Related: [Tooth Filling Costs Without Insurance]
Frequently Asked Questions About Dental Fillings:
How long does the numbness from a filling actually last?
Clinical studies on lidocaine, the most common dental anesthetic, show numbness typically lasting around 2.5 to nearly 3 hours, though this varies by individual and the specific technique used. Onset is fast — usually within about a minute of the injection.
Is amalgam really more durable than composite?
It’s more nuanced than commonly stated. While amalgam is often cited as lasting longer on average, a large study following over 8,000 restorations across roughly 800 patients found similar failure rates between the two materials overall, with composites slightly outperforming amalgam by the five-year mark in that data — individual factors like filling size, location, and oral habits matter as much as the material itself.
How long should sensitivity last after getting a filling?
Most post-filling sensitivity resolves within a few weeks, though research shows the full range extends from about one week up to several months in some cases. The key sign to watch for isn’t the exact duration but the trend — sensitivity should be gradually improving, not worsening or staying constant.
What does it mean if my filling feels “too high”?
This means the filling is sitting slightly taller than your natural bite, causing that tooth to make contact first or with extra force when you bite down. It’s a common, easily fixed issue — a quick adjustment appointment resolves it, and it shouldn’t be something you simply adjust to over time.
Can I eat right after getting a filling?
You can generally eat once numbness fully wears off, typically a few hours after the appointment. Right after the procedure, while still numb, it’s best to avoid chewing on that side to prevent accidentally biting your cheek or tongue without feeling it.
How many visits does a filling take?
Composite and amalgam fillings are almost always completed in a single visit. Gold and porcelain/ceramic fillings (technically inlays or onlays) are lab-fabricated and typically require two visits — one for the impression and a temporary filling, and a second to place the final custom restoration.
When should I actually worry about pain after a filling versus just waiting it out?
Gradual improvement over days to weeks is normal and doesn’t need intervention. Pain that’s worsening, occurring without any trigger, or specifically sharp when biting down are the patterns that warrant contacting your dentist rather than waiting.
Bottom Line
A dental filling is a routine, well-understood procedure, but “routine” hides a surprising amount of useful specificity — real anesthesia duration (roughly 2.5–3 hours), a genuinely more nuanced amalgam-versus-composite longevity picture than the common “amalgam always lasts longer” claim, and a clear, evidence-based timeline for what counts as normal sensitivity (gradually improving over one to several weeks) versus what warrants a call to your dentist. Knowing these specifics — and using the checklists above before and after your appointment — turns a routine procedure into one you can walk into, and recover from, with genuine confidence rather than guesswork.
References
- “A Pragmatic Study Shows Failure of Dental Composite Fillings Is Genetically Determined: A Contribution to the Discussion on Dental Amalgams.” PMC — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5681741/
- “How Long Do Fillings Last? 7 Types Compared.” NewMouth (citing Antony et al., GMS Health Technology Assessment, 2008) — https://www.newmouth.com/blog/how-long-fillings-last/
- “Clinical Evaluation of a New Flowable and a New Sculptable Universal Bulk-fill Composite for Direct Restorative Treatment” (citing Major et al., 2002, on post-operative hypersensitivity resolution timelines). ClinicalTrials.gov protocol — https://cdn.clinicaltrials.gov/large-docs/79/NCT06369779/Prot_SAP_002.pdf
- “A universal approach to manage dentinal hypersensitivity and postoperative sensitivity in a restorative dental practice.” Dental Economics — https://www.dentaleconomics.com/science-tech/article/16385062/a-universal-approach-to-manage-dentinal-hypersensitivity-and-postoperative-sensitivity-in-a-restorative-dental-practice
- “Evaluating Pain, Onset of Action, Duration, and Anesthetic Efficacy of Conventional and Buffered Lidocaine in Infiltration Anesthesia: A Comparative Clinical Study.” PMC — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12742648/
- “Comparison of the anesthetic effect of alkalized lidocaine versus non-alkalized lidocaine administered at a slow rate in mandibular primary molars.” PMC — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10462918/
This article summarizes findings from published clinical research; it is not a substitute for personalized advice from a licensed dentist. Always follow your own dentist’s specific aftercare instructions, which may differ based on your individual case.
