Not Enough Bone

Do you really need a sinus lift?

Is there another way around the sinus cavity at the back of the upper jaw?

If you have been told about your upper back teeth that "there isn't enough bone, you need a sinus lift first", this page is for you. We explain what a sinus lift (sinus floor elevation) is, when it is really needed and when it can be avoided. Send us your CBCT scan and we will write to you within 24 hours to tell you which group you are in.

Short answer

Not in every case. A sinus lift is done when the bone beneath the sinus cavity at the back of the upper jaw has shrunk too much to support an implant. It is not the only route: we angle the implant in front of or behind the cavity, lock it into the hard outer layer of the jaw and fit fixed teeth without opening the sinus at all. If the remaining hard walls have also resorbed, a sinus lift is needed. An ongoing sinus infection, however, is not a reason for one but an obstacle: a sinus lift is not done while there is an infection, which is treated first. A CBCT scan shows the difference.

What the decision needs: A 3D CBCT scan
Initial assessment: From your CBCT scan, within 24 hours
What decides it: The remaining hard bone walls
If a sinus lift is done: Treatment takes months longer

Medically reviewed by Bilge Ilgın, Dentist · ImplantologyLast reviewed 2026-08-31

Why the sinus cavity gets in the way of implants

At the back of the upper jaw, just above the roots of the molars, there is an air-filled space called the maxillary sinus. While your teeth are in place, there is enough bone between this space and the roots, and you never notice that it is there. When you lose a tooth, that balance is upset.

The change works in two directions. On one side, because the load of chewing is gone, the bone under the gum shrinks from lack of use; this is what we call bone resorption. On the other, the sinus cavity expands downwards over the years. Shrinking from below, expanding from above: the slice of bone in between gets thinner. This thin slice is the reason a dentist says "there's no room for an implant here".

A conventional implant anchors in the softer spongy bone inside the jaw and fuses with it over time. This kind of anchorage needs a certain height of bone. If that height is not there, the sequence goes like this: build up the bone first, wait for months, then place the implant, then wait again. A sinus lift is that first step: the thin membrane lining the floor of the sinus is lifted upwards and a bone graft is placed in the space created beneath it.

But the spongy bone beneath the sinus floor is not the only thing that decides. The hard layer surrounding the outer surface of the jaw, the cortical bone, is far more resistant to resorption and stays in place even when the spongy bone inside has largely disappeared. A strategic implant is designed to lock mechanically into this hard layer. When the measure changes from "how many millimetres of bone are there under the sinus?" to "which hard walls are still standing?", a completely different plan comes out of the same CBCT scan.

That is why the first thing we do is not plan a sinus lift but look at the condition of the remaining hard walls. There are many patients for whom we bypass the cavity; when we cannot, we tell you so and explain why. The image makes the decision, not a general rule written on a page.

When a sinus lift can be avoided, and when it cannot

The breakdown below becomes clear after the examination and CBCT scan. Seeing yourself in the second list does not mean you cannot have implants; it only means that your route goes through a sinus lift.

The tooth can be saved

The hard outer walls are intactEven if the spongy bone under the sinus has thinned, as long as the hard outer layer of the jaw is still there, we lock the implant into it. This is the most common situation in which we fit fixed teeth without touching the cavity at all.
The bone in front of and behind the cavity can be usedThe sinus cavity does not take up the whole of the back area. If the blocks of bone in front of and behind it are sound, we angle the implants and route them outside the cavity.
Many missing teethWhen a full mouth or a large area is being planned, the load does not fall on a single point, and the implants are joined together. This leaves far more placement options than a single-tooth plan.
The sinus itself is healthyIf there is no nasal congestion, recurrent sinusitis or previous sinus surgery, planning is simpler and both options stay open.

Saving it is unlikely to hold

An ongoing sinus infectionIf there is facial pain, discharge on one side or recurrent sinusitis, surgery is not carried out in that area. A sinus lift is not done while the infection continues either; the infection is treated first. The first step is not an implant but an assessment by an ear, nose and throat (ENT) specialist.
The hard walls have resorbed tooIf the resorption has not stayed in the spongy bone inside but has taken the hard outer layer with it, there is nowhere left to lock into. Here, building up bone is not an option but a prerequisite.
A single missing tooth at the backThe area we work in is many missing teeth and full mouths. For a patient whose neighbouring teeth are sound and who is missing a single molar, a conventional implant or a sinus lift is the better choice; we say so plainly.
A mass or polyp in the sinusIf a cyst, a polyp or an unexpected fullness shows up on the CBCT scan, what it is has to be established first. The implant plan has to wait for that answer.

How we make the decision

This sequence is for diagnosis, not treatment. At the end, you will know whether a sinus lift is necessary for you and why.

1
Send us your CBCT scan
If you have a cone beam CT (CBCT) scan or a panoramic X-ray, send it through the form. Our dentist Bilge Ilgın reads the image, and we write to you within 24 hours about whether a plan without a sinus lift is on the table. You do not need to come in for this step.
2
We ask about your sinus history
Is your nose constantly blocked, how many times a year do you get sinusitis, do you have allergies, have you had nose or sinus surgery before? These answers are as decisive as the CBCT scan.
3
Clinical examination
The thickness of your gums, how wide you can open your mouth, the condition of the opposite jaw and, if you have one, how your current denture fits are assessed. How the bite will be set up at the back matters as much as where the implants will go.
4
3D planning
On the CBCT scan, the course of the sinus floor, the partitions inside the cavity and the thickness of the remaining hard walls are measured. The entry points and angles of the implants are set here; this is the stage at which the decision becomes clear.
5
We set the two plans side by side
If there is an option with a sinus lift and one without, we explain both: how many visits, how long, which risks. If there is only one route, we tell you that too and explain why.

Ways around the cavity

None of them is better than the others in absolute terms. Which one is right is decided by the shape of the remaining bone, the number of missing teeth and the health of the sinus.

Open sinus lift (lateral window)

An incision is made in the gum on the cheek side, a small window is opened in the bone, the sinus membrane is carefully lifted upwards and a graft is placed beneath it. This is the method preferred when very little bone remains. It gives the greatest gain in height, and in return it needs the longest healing.

Closed sinus lift (crestal technique)

Without opening a separate window, the sinus floor is pushed up a few millimetres with special instruments through the hole where the implant will sit. Less intervention, faster healing. But it gives only a limited gain in height and needs a certain height of bone to be there to begin with.

Angled placement that bypasses the cavity

The implant is angled into the sound bone in front of or behind the sinus cavity and locked into the hard outer layer of the jaw. Because the sinus is not opened, a graft and months of waiting do not come into it; at the end of three clinical days you leave with your final fixed teeth. Whether it is suitable is decided by the remaining hard walls.

Short implants

Using an implant short enough to fit the remaining bone height is another way of avoiding a sinus lift. A Cochrane review could not show a clear difference between short implants and sinus lifts in terms of failure, but it did note that more complications were reported in areas where a sinus lift had been done.

What you need to know when deciding

We write this not to frighten you, but so that you can ask the right questions whichever clinic you go to. If a dentist does not explain these points of their own accord, ask.

The sinus membrane can tear

The membrane lining the floor of the sinus is as thin as paper and can tear as it is lifted. Small tears are repaired in the same session; with larger ones, the procedure is stopped and put off for a few months. This is the most common problem with a sinus lift.

A sinus infection can develop

After the procedure, facial pain, coloured discharge from one side of the nose or a reduced sense of smell are signs of sinusitis. Reported early, it is managed with medication; if you wait, it puts the graft at risk.

The graft may not mature as expected

A bone graft does not turn into bone at the same rate in every patient. Smoking and uncontrolled blood sugar are two factors that make this process harder. If it has not matured enough, the implant stage is postponed.

Treatment is split in two and takes longer

When a sinus lift is done, first comes the graft surgery, then months of waiting, then the implant surgery, then another period of fusion. The American Academy of Periodontology describes this waiting period as between four and twelve months. For a patient travelling from abroad, that means two trips instead of one.

"No sinus lift needed" does not solve everything

Being able to bypass the cavity does not mean the other conditions have gone away. Gum inflammation, uncontrolled blood sugar, smoking and problems in the opposite jaw remain part of the plan. If one of these is present, we deal with it first.

What to expect afterwards

Of the headings below, the first two apply when a sinus lift is done, and the last two apply to a plan in which the cavity is bypassed. The two sequences differ sharply in both time and restrictions.

The first week after a sinus lift
Swelling and bruising on the cheek are normal. During this period we ask you not to blow your nose, to keep your mouth open when you sneeze, not to drink through a straw and to avoid flying and diving. The aim is to avoid building up pressure in the sinus; pressure can shift a graft that has not yet settled.
The months after a sinus lift
You wait for the graft to mature, then the implants are placed, then there is another wait for fusion. You spend this period with a temporary denture. This route is measured in months; there is no clear end date at the start.
Three clinical days on the bypass plan
When the sinus is not opened, the implants are placed and your final fixed teeth are fitted within three clinical days. You do not leave the clinic without teeth. There is some mild swelling and tenderness in the first few days.
The first weeks on the bypass plan
A period of soft food, brushing the area gently and avoiding hard foods. We carry out check-ups remotely by photo and ask you to come in when needed. After that, care is no different from caring for natural teeth: brushing, interdental cleaning and regular check-ups.

Message us right away if

Bleeding or discharge from the nose that does not stop. A slight bloody ooze in the first days after a sinus lift is normal; discharge that continues or increases should be assessed.
A fever or pain on one side of the face. These two signs together point to a sinus infection. Call without waiting.
Swelling that gets worse after the third day. Swelling goes down as you heal; if it is getting worse, it should be assessed.

What determines the cost

We do not give figures on this page, because the right figure can only be given once the CBCT scan has been seen, and the difference between a plan with a sinus lift and one without is not small. Send us your CBCT scan and we will share the scope and the figure in writing. These are the items that determine the total:

Whether a sinus lift is needed: A sinus lift means a separate operation, separate graft material and a separate healing period. When this item comes into play, the plan becomes both longer and larger.
Open or closed technique: The open technique, done through a lateral window, takes longer and uses more material than the closed technique, done by the crestal route. Which one is used is decided by the remaining bone height.
Number and spread of implants: A single area, the whole back area or a full mouth. As the scope widens, the bridgework to be made on top grows along with the number of implants.
Bridgework: The material of the fixed teeth made on the implants and the laboratory work directly affect the total. We tell you in writing, from the start, the brand of the material we use.

Frequently asked questions

A clinic told me "sinus lift first, implants six months later". Should I get a second opinion?

That plan is not wrong; it is a reasonable decision that a dentist working with conventional implants might make by looking at the remaining bone. But it is not the only possible decision: when the measure is "how many millimetres of bone are there under the sinus?", one plan comes out, and when it is "which hard walls are still standing?", another does. When you ask for a second opinion, take your CBCT scan with you; when two dentists are not looking at the same image, they have assessed different things. If you send it to us, we give you a second opinion in writing, free of charge.

I was told "you have no bone at all". Is there really no bone?

"No bone at all" means this: under the sinus cavity, there is no height left for a conventional implant to anchor in. The hard outer layer of the jaw, however, is still in place, and that is where a strategic implant anchors. We look at the image and write to you about what your own CBCT scan shows; but do not take that statement as the final word.

Is a sinus lift painful?

The procedure is done under local anaesthetic; you do not feel pain during it, because the area is numbed and what you feel is pressure and vibration. In the days that follow there is swelling, bruising on the cheek and a feeling of pressure; the painkillers you are given deal with this. The hard part is not the pain but the restrictions: for a while you need to avoid blowing your nose and flying.

If I have a sinus lift, how long will I have to wait?

The maturing of the graft is measured in months. The American Academy of Periodontology describes the waiting period before implants are placed as between four and twelve months. The time depends on the remaining bone, the type of graft and how you heal. If you are travelling from abroad, that means two trips instead of one.

Will an implant placed without a sinus lift cause problems later?

Placement that bypasses the sinus is not a matter of forcing an implant into bone it does not fit; it is a different plan that uses the remaining hard walls. If it is forced in an unsuitable mouth, it will cause problems. That is why we do not select cases without a CBCT scan, and when we do not find a case suitable, we say so.

I have sinusitis. Can I have implants?

While there is an ongoing sinus infection, surgery is not carried out in that area, and a sinus lift is not done either. The sinusitis is treated first, starting with an assessment by an ENT specialist. Once the infection has cleared, both the sinus lift and the bypass option are back on the table. It is not a case of the door closing but of the order changing.

I have diabetes. Is a sinus lift riskier for me?

If your blood sugar is under control, surgery can go ahead; if it is uncontrolled, healing and the maturing of the graft become more difficult. The advantage of the protocol we use for people with diabetes is that it takes the graft and the months of waiting off the table entirely. We make the assessment using your current readings.

Why don't you put prices on the page?

Because the scope of a plan with a sinus lift is very different from one without, and we cannot say which one applies to you without seeing the CBCT scan. Any figure we wrote would either put you off unnecessarily or change at the clinic. Send us your CBCT scan and we will share the scope in writing, item by item.

Sources

Send your X-ray and we will tell you which option is realistic for your tooth.

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Next step

Send your X-ray and we will talk through the options.

Share your CBCT or panoramic X-ray. We will write back within 24 hours on which option is realistic for your tooth.

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