Check the Height Before Anything Else

A week after fillings, somebody asks the reasonable question:

I’m still sensitive after getting the cavities filled a week ago. Is that normal? r/askdentists

And ten months later, somebody else asks the same question with a longer timeline:

I had 4 fillings last October and my teeth are still significantly more sensitive than they were before. Should I be worried? r/askdentists

Those two situations have completely different answers, and the boundary between them is roughly four to six weeks.

Some sensitivity is expected

The reassuring version, from somebody who went through it:

some of my teeth were more sensitive than usual for a little while after, but that’s pretty normal according to my dentist and it went away! r/askdentists

Placing a filling involves drilling, which generates heat and vibration close to the pulp, and then bonding a material to freshly cut dentin. The nerve responds to all of that by inflaming, mildly, and it takes weeks rather than days to settle.

Normal looks like: a twinge on cold, a twinge on biting, steadily less each week, gone by four to six.

Not normal looks like: getting worse, unchanged after six weeks, pain that lingers after the cold has gone, throbbing on its own, or waking you at night.

The cause that gets missed

This is the single most useful reply in the whole subject, and it names something almost nobody thinks of:

You should go back and have it fixed! Make sure they also check the height of the fillings which might be too high and cause you pain/sensitivity! The dentist should check the contact points between your teeth after a filling r/askdentists

A filling that is fractionally too high.

Teeth meet as a set. If one filling stands a fraction of a millimeter above where the original tooth surface was, that tooth takes the first contact and the hardest contact every single time the jaw closes — swallowing, chewing, clenching. Thousands of times a day.

The result is a nerve under continuous mechanical insult, and it presents exactly as sensitivity. It also produces a tooth that is tender to bite on, which is the distinguishing sign.

The fix takes minutes. You bite on a strip of colored paper, the dentist sees where the mark is heaviest, and grinds a whisker off. That’s the whole procedure.

Which is why the shorter version of the advice is: if a new filling is sensitive to biting, ask them to check the bite before anything else.

Somebody in the same thread had noticed the blue paper and hadn’t connected it:

they’re always new fillings, like it’s uneven with the part of the tooth under the gums. Never been flossed after a filling though, only made to bite on this blue thing. r/askdentists

The blue thing is the check. And the flossing remark points at the other adjustment — a rough contact point between the filling and the tooth next to it, which traps floss, shreds it, and holds plaque. That’s also a five-minute fix, and it’s also worth asking about.

The other explanations, in order of likelihood

Height. Above. Check first.

Rough or overhanging edge, catching floss and collecting plaque at the gum line.

A deep filling close to the pulp. Some cavities go far enough that only a thin layer of dentin separates the material from the nerve. These take longest to settle and occasionally don’t, which is when a root canal becomes the conversation.

Shrinkage of the material. Composite contracts slightly as it sets, and if the seal at the margin isn’t perfect, fluid movement under the filling reaches the nerve. Presents as a sharp cold sensitivity that doesn’t fade.

Or the tooth was already inflamed before the filling, and the filling didn’t cause it. A cavity deep enough to need filling has often already irritated the pulp — the treatment just arrives at the moment the symptoms are noticed.

And one reason not to avoid fillings for sensitivity

Worth including because it points the other way. A dentist on filling teeth that were sensitive before any treatment:

If they are sensitive, get them filled. I had patients who still have the fillings after 10-15 years and marked reduction in sensitivity. r/askdentists

That’s about a specific situation — notched wear at the gum line, where exposed dentin is the cause of the sensitivity and covering it is the fix. Ten to fifteen years is a good run.

Why nobody tells you in advance

The most honest thing said in any of these threads was said by a dentist about themselves:

I always explain possible post op situations. If I tell a patient their filling may be sensitive and it’s sensitive, it’s fine. If I don’t and it’s sensitive, the patient assumes I r/askdentists

Same outcome, different experience, and the variable is whether it was mentioned beforehand.

Which is a reason to ask before the appointment rather than after: how sensitive should this be, for how long, and at what point should I come back? Three questions, and the answers turn six weeks of quiet worry into a schedule.

The short version

Two to four weeks of fading sensitivity is normal. Getting worse, or unchanged after six weeks, is not.

If it hurts to bite on, ask them to check the height first. That is the commonest cause, it does not resolve on its own, and it is fixed with a strip of paper and a few seconds of polishing.

And pain that lingers after the cold has gone is about the nerve, not the filling.