A bone graft from your own tooth: can an extracted tooth be used as a graft?

Most of a tooth is made up of dentin. Like bone, dentin is a tissue made of mineral crystals and collagen, and it contains growth factors. A review of tooth-derived graft materials by a team of Korean and Japanese researchers explains that proteins that stimulate bone formation have been obtained from mammalian teeth, and that this observation was the source of the idea of making a bone substitute from teeth. The same team reports that processing extracted teeth into graft material has been used clinically in Korea since 2008, and that this material is gradually resorbed and replaced by new bone.

There are two main ways of preparing a tooth as a graft. In the first, the tooth is sent to a laboratory, a centre known as a 'tooth bank'; there it goes through drying, defatting, freeze-drying and sterilisation, and comes back days later as a graft. In the second, everything happens in the same session, in the dental practice: the tooth is cleaned with a bur, the gum fibres and enamel are scraped off, it is broken into particles in a special grinder, soaked in a disinfecting solution and rinsed. In one study these last two steps took 7 and 3 minutes; it was also noted that the pulp was discarded because the grinder cannot grind soft tissue.

The most studied use is preserving the extraction socket. After a tooth is removed, the walls of the socket resorb; placing a graft in the socket aims to reduce this loss. In a recent meta-analysis pooling 14 studies, tooth graft preserved bone width significantly better than an empty socket; there was no difference in width between it and other graft materials. In bone height, however, there is no significant difference compared with either an empty socket or other grafts. In biopsies, the proportion of new bone was higher than with other grafts and no different from an empty socket. The authors rate the evidence as moderate for the width and bone formation results and low for height, and note that most of the studies are small and carry a risk of bias.

Another meta-analysis looking only at randomised studies paints a more positive picture: in 10 studies with 182 participants, horizontal bone loss in sockets where ground tooth graft was used was on average 1.61 millimetres less than in sockets healing with their own blood clot, and 1.28 millimetres less than with other grafts. The authors nevertheless write that larger studies with longer follow-up are needed to show superiority over other materials. The two reviews come out differently on the 'comparison with other grafts'; this is a sign that the evidence has not yet settled.

Results at tissue level have also been pooled. In a meta-analysis combining the biopsy data of six studies, the proportion of newly formed bone was on average 40.23%, and the proportion of remaining graft 11.61%. The same study reports that the proportion of new bone was higher with grafts prepared from both the root and the crown of the tooth rather than from the root alone, and that removing the tooth's mineral completely tended to lower the proportion of new bone. In a small series of ten people, the proportion of new bone was measured at 16.3% at three months, 41.1% at six months, 54.5% at twelve months and 59.4% at twenty-four months. Follow-up of this kind shows that the graft is resorbed over time and turns into bone, but a series of ten people is not enough to generalise from.

On the implant side, the data are positive but short-term. In a review of 20 articles on tooth graft prepared in the dental practice, implant survival was 98.8% for implants placed after the graft had healed and 97.4% for those placed in the same session. In an older review, survival in 182 implants was 97.7%, but in the same review the most common complication was the wound edges opening, at a rate of 29.1%. The authors of this review state plainly that there is not enough evidence to draw firm conclusions. The review of graft prepared in the dental practice also notes that the studies are small, follow-up is short and most have no control group.

For larger bone defects, the root of the tooth has also been used as a block, without being ground. In a meta-analysis of four controlled studies comparing a tooth block with a bone block taken from the jaw for widening the side wall of the jaw, the tooth block gained on average 1.31 millimetres more width and resorbed less; there was no difference in complications. Because taking a block of your own bone means a second surgical site, this result is of interest. But the data cover a total of 77 participants; the authors write that longer follow-up is needed.

Before discussing tooth graft and other bone granules, there is one more question to ask: is a graft really needed? Preserving the extraction socket makes sense in plans where the implant will be placed months later with the conventional method. If the implant will be placed in the same session, or if there is a plan in which the implant takes its hold from the deep bone of the jaw, the need changes. Before asking about the graft itself, you should ask what the plan is.

With tooth graft, two things are assessed together: the extracted tooth itself and the place where the graft will go. The distinction below is based on the criteria used in the studies and on general surgical principles.

The sequence below is the general course for a tooth graft prepared in the same session in the dental practice. Timings and solutions vary with the device and the method.

1. 1

   Planning and choosing the tooth

   Whether a graft is needed, where it will go and whether the tooth to be extracted is suitable as a source are assessed in advance. For root-canal-treated or filled teeth, whether cleaning is possible is discussed at this stage.

2. 2

   Extracting the tooth

   The tooth is extracted while preserving the walls of the socket. The extracted tooth is taken for preparation without being left to dry out.

3. 3

   Cleaning

   The tooth is cleaned with a bur: the gum fibres surrounding the root and any decay, fillings and root canal filling are removed. In one study the enamel was also scraped off, leaving mostly dentin.

4. 4

   Grinding

   The dried tooth is broken into particles in a special grinder and sieved by size. In one study the particles were between 300 and 1,200 micrometres. Because the pulp cannot be ground, it is discarded.

5. 5

   Disinfection and rinsing

   The particles are soaked in a disinfecting solution and rinsed. In one method these steps took 7 and 3 minutes; another device uses an automatic 25-minute demineralisation process.

6. 6

   Placing the graft and closing

   The prepared graft is placed into the extraction socket or the bone defect, a resorbable membrane is often placed over it and the gum is closed. Because the wound edges opening is the complication most often reported in the review, closure needs care.

7. 7

   Waiting and the implant

   In studies, biopsies were mostly taken between the third and sixth months; the graft continues to turn into bone in the months after that. When the implant is placed is decided according to a check image of the area.

Tooth graft is a new member of the bone graft family. We have described the pros and cons of the other sources in detail on our bone graft material page; here we compare them briefly.

Being your own tissue is an advantage in immune terms, but it does not remove the surgical risks of a graft or the limits of the evidence.

Healing follows the course of a tooth extraction with a graft. What needs the most attention is that the wound edges stay closed in the first few weeks.

1. The first few days

   Pain and swelling similar to those after an extraction are to be expected. Not touching the area with your tongue or finger, not rinsing hard on the first day and not smoking help the wound stay closed.

2. The first two weeks

   It is not unusual to see small particles like grains of sand in your mouth; losing a few particles from the surface is usually not a problem. A noticeable opening or particles coming out continuously needs checking.

3. The third to sixth month

   The graft is resorbed and replaced by bone. In studies, the proportion of new bone was measured at around 40% at six months and continued to increase in the months that followed.

4. The implant stage

   The width and height of the area are assessed on a check image, and the implant plan is finalised accordingly.

You will not find figures here. With tooth graft, these are the items that change the quote:

Preparation method

Grinding in the same session in the dental practice and sending the tooth to a centre for processing mean different costs and timelines. The solutions the devices use and single-use parts also add to the cost.

Membrane and additional materials

A membrane placed over the graft, or blood products mixed with the graft, are separate items.

Whether a graft is really needed

This is where the biggest difference lies. Where the implant is placed in the same session or the work is done with a plan that needs no graft, socket preservation may not come into it at all.