When does the graft placed in a sinus lift turn to bone, and can that time be shortened?

What is placed in the cavity in a sinus floor elevation is not bone but a material that stands in for bone. Whether it is taken from your own bone or comes from a donor, an animal or a synthetic source, the granules are no more than a scaffold on the day they are placed, and on their own they do not carry an implant. Over the months that follow, blood vessels and bone-forming cells advance inwards from the surrounding bone walls, the spaces between the granules fill with new bone, and some of the granules dissolve. That is what turning to bone means: not becoming stone, but the site being taken over step by step.

How far that takeover has got is established by measurement. When the slim cylinder of tissue taken from the site as the implant socket is prepared is examined under a microscope, three things are counted as percentages: new bone, residual graft particles still in place, and the soft tissue in between. This method, called histomorphometry, is the only concrete answer to the question of whether the graft has turned to bone.

One of the studies testing the timing directly was published in the Brazilian Dental Journal in 2026. The same bovine graft was placed in both sides of the upper jaw in fourteen patients missing teeth on both sides, one side was left for four months and the other for eight, and a sample was taken from both sides as the implants were placed. The new bone proportion came out at 20.02% at four months and 28.22% at eight, and the difference was significant. The residual graft proportion ran in the opposite direction: 39.12% at four months and 31.65% at eight. In total 28 sinuses were grafted and 54 implants placed.

Here is the point easy to miss: even at the end of the eighth month, about a third of the sample was still the material that had been placed. Because bovine granules dissolve very slowly, some of them can stay in place for a long time. So there is no threshold at which the graft has turned entirely into your own bone; what happens is that the proportions shift in favour of new bone.

The type of graft changes these proportions. The meta-analysis published in Tissue Engineering Part B, combining 64 publications, gives total bone volume at around 63% for sinus grafts done with your own bone; with donor, animal and synthetic materials this value is between 7% and 26% lower. The network meta-analysis published in the International Journal of Implant Dentistry in 2025 finds the same order: your own bone gives 12.33% more new bone than biphasic calcium phosphate, donor bone 5.14% more, and bovine graft 4.14% less.

That order, though, is small beside the differences between studies. In the same review's table, the new bone percentages reported by the studies spread across a wide range, from under 20% to 43%. In a randomised trial that set four materials side by side within a single piece of research, 42.74% was measured with your own bone, 35.41% with donor bone, 30.28% with biphasic calcium phosphate and 24.9% with bovine graft. In another study, bovine graft came out at the top with 41.6%.

As for how long the wait should be: the systematic review published in the Journal of Periodontal Research, which searched 136 human studies, finds that the new bone proportion is significantly higher in grafts left for longer than four and a half months. The same review finds no difference in most materials between samples taken at a mean of 6.22 months and those taken at a mean of 10.36 months; the one exception is donor bone. So the threshold the review measures is four and a half months; in samples taken beyond that, the new bone comes out significantly higher, while extending beyond nine months does not by itself increase the bone measured, except with donor bone.

There is one more question, and it puts the whole argument about percentages in its place: does a high new bone proportion make the implant stay? The authors of the meta-analysis above write that this is still unresolved. In the long-term review in the Journal of Clinical Periodontology, annual implant loss is 0.43%, and neither when the implant was placed nor the type of graft makes a difference to that loss. In the review of 7,902 implants published in Periodontology 2000 in 2026, the survival rate at between five and thirteen years is 95.8%; the certainty of the evidence is marked as low.

The route we work with gets past this waiting problem not by speeding up the graft's maturation but by changing the layer of bone the implant holds in. The strategic implant is planned so that it locks mechanically into the hard outer shell of the jaw, that is, into the cortical bone; because no bone graft is used, the step of waiting for a graft to turn to bone is not in the protocol. This is not a claim of superiority but a different route: in mouths where the hard shell has wasted away too, the right answer is a plan with a graft. Which group you are in is shown by a CBCT scan.

The distinction below shows the situations where the argument about waiting time counts for something in practice, and the ones where it does not. None of it stands in for a personal assessment.

The sequence below describes the period after a sinus floor elevation done with the open technique. The timings shift with the person, the material and the bone that is left.

1. 1

   The first few days: the clot and settling in place

   When the granules are placed, the spaces between them fill with a blood clot, and it is largely thanks to that clot that the material stays where it is. That is why things that create pressure inside the sinus, such as blowing your nose hard and drinking through a straw, are restricted in this early period.

2. 2

   The first weeks: blood supply and advance from the edges

   New bone does not appear out of thin air; it advances from the surrounding bone walls. A histomorphometric study in rabbits reports that mineralised bone increased between the second and fourth weeks, stayed level between the fourth and eighth, and that the most new bone was found in the regions close to the sinus's bone walls. This is an animal study; it does not give the timetable in people exactly.

3. 3

   The follow-up image

   What is looked at on an image taken months later is whether the graft has kept its volume, and its density. There is an important limit: an image cannot tell new bone apart from graft particles that are still in place. Only the microscope makes that distinction.

4. 4

   Taking a sample and histomorphometry

   All the percentages in clinical studies come from the cylinder of tissue taken as the implant socket is prepared. In routine treatment a sample is not taken from every patient; this is a research step. The sentence you are told, that the graft has turned to bone, most often rests on the image and on the resistance the drill gives as the socket is prepared.

5. 5

   Placing the implant, primary stability and loading

   The primary stability measured as the implant is placed is counted as an indirect indicator of the state of the graft; there are randomised data showing that this value can come out lower in implants placed early. Attaching a tooth on top is a separate decision, and it usually brings another wait of its own. The total length of a plan with a graft is the graft's maturation plus the implant's fusion to bone; that is what really stretches the timetable.

The fast-healing formula going round is not one thing; there are several separate claims underneath it. The evidence for each stands in a different place.

What follows are not the risks of the surgery but the risks in the decision. The sinus lift's own surgical risks sit on a separate page.

If a graft has been placed, the months that follow are not empty months but monitored ones. The intervals below are a general framework; the timetable your dentist gives you takes precedence.

1. The first two weeks

   Swelling and bruising on the cheek are usual, and the stitches are removed during this period. The rule about not creating pressure inside the sinus applies most strictly in these weeks: blowing your nose hard, drinking through a straw and flying are all on that list.

2. Between the first and third month

   Daily life returns to normal and the area looks quiet; that quiet does not mean the maturing is over. If you are wearing a temporary removable denture, it has to be adjusted so that it does not press on the graft site.

3. From the fourth month onwards

   In the literature, the new bone measured after waits shorter than four and a half months is significantly lower. Talk of the implant generally begins in this window, and the follow-up image is taken in this period.

4. Around the sixth month

   In randomised trials the wait is mostly between five and ten months. The review named above finds that extending beyond nine months brings no measurable extra gain with most materials.

There are no figures here. The waiting time often does not appear as a separate line, but it directly sets the scope of the plan and the travel timetable. The headings to look at when reading a quote:

How many stages it is split into

Are the graft and the implant done in the same session, or are two separate operations needed months apart? This decision affects the number of visits and the total length more than anything else.

How many visits and how many journeys

If the wait is measured in months, then for a patient coming from another city or from outside Turkey this means two journeys instead of one.

The temporary solution for the interim

What you will be wearing in your mouth throughout the wait is a heading that needs discussing separately. Making the temporary denture, and the adjustments needed so that it does not press on the area, go into the plan.

Added procedures meant to speed things up

Extra headings such as a platelet concentrate or a growth factor are priced as a separate line in most clinics. Ask which measurable outcome is expected to change in return.