Last updated: August 2026
It is one of the most common questions we take on the phone, and it is the one we are least able to answer on the phone. Somebody has been told, sometimes years ago, that they do not have enough bone for an implant. Or they have read that a graft might be needed and want to know whether that applies to them before they book anything.
Nobody can tell you from a description. Not us, not anyone. The bone that matters is hidden under gum tissue, it varies from one site in your mouth to the next, and the measurement that usually decides the answer is invisible on the kind of X-ray most people have had.
What we can do is explain what is being measured, why bone disappears in the first place, what a graft actually involves when one is needed, and what the assessment looks like. Then the answer for your own mouth becomes a short appointment rather than a mystery.
Jawbone is not a fixed shelf that teeth happen to sit in. It is living tissue that maintains itself in response to load. A tooth root transmits the forces of chewing into the surrounding bone, and the bone responds by keeping itself dense and keeping its shape.
Take the root away and that signal stops. The bone around the empty socket begins to remodel and shrink. The change is fastest in the first several months after an extraction, then continues slowly for years. It happens in two directions at once: the ridge gets shorter from the top and narrower from the sides, and the narrowing is usually the bigger problem.
Several things speed the process up:
That last point is the one we see most. Plenty of people in the long-established residential pockets around Churinga, McAdam Square and Burnt Bridge have lived comfortably with a gap for fifteen or twenty years, chewing on the other side without much thought, until a second tooth starts to give trouble and the whole question comes up at once. The gap was never the problem. What the years did to the ridge underneath it is the thing that now needs planning.
When a dentist says there may not be enough bone, they can mean any of three different things.
Height is how much bone there is from the top of the ridge down to a structure that must not be touched. In the lower jaw that structure is the inferior alveolar nerve, which runs through a canal inside the bone and supplies feeling to the lip and chin. In the upper back jaw it is the floor of the maxillary sinus. Height sets how long an implant can be.
Width is how thick the ridge is from cheek side to tongue side. An implant needs bone all the way around it, not just underneath it, so a ridge can be perfectly tall and still be too thin to hold a fixture with bone on both faces. Width is the measurement that most often triggers a graft, and it is the one a flat X-ray cannot show.
Quality is how dense the bone is. Dense bone grips an implant firmly the moment it is placed. Softer, more open bone, which is more common in the upper back jaw, grips less firmly at placement and changes how the treatment is staged.
You can have plenty of one and not enough of another. This is why a straight yes or no answer over the phone is not available: the question is not one question.
A standard dental radiograph is a flat image. It flattens the mouth from the front, which means it compresses exactly the direction width runs in. You can look at a two dimensional film and see the bone height, the neighbouring roots and the general lie of the land. You cannot see whether the ridge is a healthy thickness or a knife edge, because both look identical from the front.
A cone beam CT scan solves that. It captures the jaw as a three dimensional volume, so the site can be sliced and viewed in cross section. On a cross section the ridge is shown end on, and the width becomes an actual measurement rather than an assumption. The same scan shows where the nerve canal runs, how low the sinus floor sits, whether there is a retained root fragment or an infection at the site, and how much room the neighbouring roots leave.
Our scanner is on site here on Wicklow Avenue. That matters more practically than it sounds. It means no referral to an external imaging clinic, no separate appointment down Maroondah Highway to have pictures taken, and no waiting for a report to travel back before planning can begin. The scan happens during your assessment, and the person planning your case is the person looking at the images with you on the screen.
There is no single number you can hold up against your own jaw, and any figure quoted as a universal rule should be treated carefully. What counts as enough depends on the diameter and length of the implant being considered, where in the mouth it is going, how much force that site takes when you chew, what the neighbouring teeth are doing, and how close the nerve or sinus sits.
A narrow lower front site and a broad lower molar site have different requirements. An upper back site sitting under a low sinus is a different planning problem again. The useful version of the question is not how many millimetres you have. It is whether the bone you have will hold the implant this site needs, and that is a judgement made on the scan, site by site.
The word graft makes people picture something far larger than the usual reality. In dentistry it generally means adding material to a site so your own bone has a scaffold to grow into and gradually replace. There are a few distinct procedures under the one word.
Done at the same time as an extraction. Once the tooth is out, graft material is placed into the socket and covered, so the walls of the socket are supported while healing happens. It does not stop every bit of shrinkage, but it helps the ridge keep more of its shape. This is the version that avoids larger work later, and it is only available at one moment: the day the tooth comes out. If you know a tooth is coming out and an implant is a possibility down the track, raise it before the extraction, not after.
Adding width, or occasionally height, to a ridge that has already shrunk. Graft material is placed against the ridge and held under a membrane while it consolidates. This is the common answer for a site where a tooth has been gone for years and the ridge has thinned.
For the upper back teeth. The maxillary sinus is an air space above the roots, and when an upper molar has been missing a while the sinus floor can end up sitting low over the ridge. The membrane lining that floor is lifted and graft material placed underneath, which builds height where there was air. Where only a small amount is needed this is done through the implant site itself. Where more is needed it is approached through a small window in the side wall.
Options include a small amount of your own bone collected during the procedure, processed graft material of human or animal origin that has been treated so only the mineral scaffold remains, and fully synthetic mineral granules. Each behaves slightly differently in how quickly it is replaced by your own bone. Your dentist will tell you which is being used and why before anything is placed.
Grafting is done under local anaesthetic. Afterwards, expect soreness and swelling for several days, with the swelling usually peaking around day two or three, and expect to be on a soft diet for a period while the site settles. You will be given specific aftercare instructions, and they are worth following closely, because the early weeks are when a graft is most easily disturbed.
Beyond that first week, life goes on normally. A graft healing period is months of ordinary living, not months of being unwell. People go back to work, do the shopping at Croydon Central on Kent Street, eat properly on the other side of the mouth and largely forget about it between reviews. What they cannot do is bring the implant forward. The bone needs the time it needs.
Bring a current list of your medications to the assessment, and be specific about two categories in particular.
Bone-modifying medications. Drugs such as bisphosphonates and denosumab are prescribed for osteoporosis and for some other conditions. They change how bone remodels, which is exactly the process an implant and a graft rely on. These are usually started elsewhere, after a bone density scan or a fracture, so a dental practice will not know about them unless you say. If those appointments have been at Maroondah Hospital on Mount Dandenong Road or with specialist rooms nearby, ask for the drug name, the dose and roughly when you started, and bring that with you.
Smoking and diabetes. Both affect healing at a graft site. Neither automatically rules treatment out, but both change how a case is planned and discussed, and it is better to have that conversation at the start.
Also worth mentioning: any history of gum disease, previous grafting attempts, radiotherapy to the head or neck, and any blood-thinning medication.
Once a scan exists, it can be used for more than answering yes or no. The 3D data can be combined with a digital scan of your teeth taken with an intraoral scanner, and the implant position planned on screen before anything is done in the mouth. From that plan a surgical guide is produced, which sits over the teeth and directs the drill along the planned path.
This matters most in exactly the situations this article is about. Where bone is limited, the difference between a workable position and an unworkable one can be a couple of millimetres and a few degrees of angle. Planning that on a screen, where it can be adjusted freely, is a more controlled way to work than judging it by eye in the moment. Our page on guided implant surgery in Croydon explains how the planning and the guide fit together, and our bone grafting page covers the graft procedures themselves in more detail.
The digital scan is also the reason there is no putty involved. An intraoral scanner captures the arch with a small handheld wand, which is a better experience for anyone who has struggled with impression trays in the past, and it produces a file that can be merged directly with the CT data.
We do not publish a price for grafting, because the honest version of the answer depends on what the scan shows. A small amount of material placed into a socket during an extraction and a staged ridge rebuild followed months later by an implant are different amounts of work, different appointment counts and different healing timelines. Quoting the first figure to somebody who needs the second would be misleading, and finding out mid treatment is a poor way to learn what you agreed to.
What you should expect is a written breakdown by stage, given before anything starts, so you can see what each part covers and when it falls due. Our article on why implant quotes vary so much sets out the stages that sit behind those figures.
On health funds: implant related work generally falls under major dental, which commonly carries a waiting period, and because treatment is staged the benefit is often claimed across more than one item number and sometimes across two calendar years. We are preferred providers with the major funds and our private health insurance page lists which. Your fund is the authority on your own policy, so confirm the detail with them before starting.
On DVA: block bone grafting is not funded, and neither are mini implants or zygomatic implants. DVA does fund implants in defined circumstances with prior approval, and restricts the surgical phase to an oral and maxillofacial surgeon, oral surgeon or periodontist. That is a policy rule about who performs a phase, not a limit on what a general dentist can do. Our DVA dentist in Croydon page covers the rules in full.
The appointment is straightforward. We examine the site and the teeth either side, check the gum health around it, take the cone beam CT here rather than sending you elsewhere, and look at the cross sections with you. From that you get a plain answer to three things: whether the bone at that site will hold an implant as it stands, what would be needed if it will not, and what the sequence and timeline would be.
Sometimes the answer is better than expected. A site somebody was told years ago was hopeless can look workable on a modern scan, because the assessment they were given was made from a flat film. Sometimes the answer is that grafting is needed first. Either way you leave knowing, rather than guessing.
We have ten dentists here, so appointment times are usually available across the week, including Saturdays from 8:30am to 5:00pm, which suits people who would rather not take a weekday off for a longer planning appointment.
Call (03) 9725 8040 or book online. We are at 59 Wicklow Avenue, Croydon. If you would like the wider picture of implant treatment before you come in, our dental implants page covers the full sequence from assessment through to the final crown.
DVA funding rules described here are drawn from the Department of Veterans Affairs and were last checked in August 2026. Health fund benefits vary by policy and are set by your fund. This article is general information, not personal dental advice; your dentist will assess your individual clinical need.