What is a block bone graft?
In a block bone graft, a solid piece of bone is taken and fixed with small screws to the place where bone is missing. According to the patient information of Cambridge University Hospitals, this technique is chosen when more extensive grafting is needed; the block can come from a bone bank or from the patient’s own hip, jaw, chin or skull. Unlike granular material, a block keeps its shape and gives the rebuilt section its contour at once.
According to the patient information of Guy’s and St Thomas’ NHS Foundation Trust, the procedure with bone from the jaw runs like this:
- The gum is lifted and the amount of bone needed is assessed.
- A piece of bone is taken, usually from the back of the jaw or the chin.
- The block is fixed to the defect with small pins or screws.
- The gum is put back and stitched; the stitches are removed about a week later.
According to the same source, the procedure usually takes 1 to 1.5 hours and a course of antibiotics is given. What bone grafting is in general is explained in our guide bone graft before implants; the materials are compared in types of bone grafting.
When is a bone block needed?
A block comes into question when the jaw has far too little bone in width or height for an implant. According to the 2008 consensus statement of the International Team for Implantology (ITI), by Jensen and Terheyden, widening a narrow jaw frequently requires a block of the patient’s own bone; blocks achieved more width and fewer complications than granular material.
Blocks are also mostly used to gain height, although according to the ITI more complications and additional grafting must then be expected. According to the review by Zhao and colleagues in Molecules (2021), blocks from the back of the lower jaw suit sections whose bone is thinner than 4 millimetres and that span up to four teeth. For smaller defects, granular material with a membrane is often enough; see guided bone regeneration. The extent of bone loss is measured on a cone-beam CT (CBCT) scan.
Where does the bone come from?
| Donor site | When? | What to bear in mind |
|---|---|---|
| Chin | When little bone is enough | Temporary altered sensation of the lower front teeth and chin skin more frequent |
| Back of the lower jaw (ramus) | When little bone is enough | Less discomfort than the chin; closeness to the lower jaw nerve requires care |
| Hip (iliac crest) | When a lot of bone is needed | General anaesthetic and short hospital stay; pain when walking possible |
The table summarises information from Guy’s and St Thomas’, Reininger and colleagues and Zhao and colleagues. According to Guy’s and St Thomas’, discomfort in the hip can be worse when walking and last 2 to 4 weeks; most people can return to work about a week later, and energetic sport should be avoided for 3 to 4 weeks. The consent form of Kahramanmaraş Sütçü İmam University for iliac crest grafts lists temporary difficulty walking, chronic pain and injury to nerves or blood vessels as risks.
What discomfort can occur at the donor site?
Most common is altered sensation in the teeth, gum, lip or chin near the donor site, which usually passes. According to the systematic review by Reininger and colleagues (2016) in Medicina Oral:
- After harvesting from the chin, temporary altered sensation of the lower front teeth was most frequent (33.87 percent), followed by altered sensation of the skin and oral mucosa (18.57 percent).
- After harvesting from the back of the lower jaw, temporary altered sensation of the oral mucosa (8.19 percent) and minor bleeding (6.55 percent) were most frequent.
The authors conclude that complaints are more frequent and more pronounced after harvesting from the chin. In the review by Tay and colleagues (2020), 7 percent of patients with a block of their own bone reported altered sensation at the donor site, which mostly resolved within 2 to 6 months.
The consent form of Kahramanmaraş Sütçü İmam University for ramus harvesting names numbness of the lip, chin, gum and tongue that can last weeks, months or, rarely, permanently, as well as bleeding, swelling, infection, restricted mouth opening and jaw fracture. Cambridge University Hospitals counts numbness of the lip and cheek and a dimple in the chin among the donor site risks. Why numbness occurs and what is done if it persists is explained in numbness after dental implants.
What problems can occur at the grafted site?
At the grafted site, infection, opening of the gum and failure to heal are possible. According to Tay and colleagues, minor infections were considerably more frequent with blocks than with granular material (5.7 versus 0.4 percent of sites). The 2009 Cochrane review (Esposito and colleagues) considers complications in bone grafting frequent, especially when height is gained. Cleveland Clinic names infection, nerve damage and severe bleeding among the general risks of bone grafting, and smoking as a factor that raises the chance of failure. What is done about exposed material or infection is described in healing after a bone graft.
What are the alternatives to a bone block?
Depending on the type of defect, smaller procedures come into question:
- Grafting with a membrane: for smaller defects, granular material is covered with a membrane; see guided bone regeneration.
- Short implants: according to the 2018 ITI consensus statement, the survival rate of implants of 6 millimetres or less after 1 to 5 years was on average 96 percent, that of longer implants 98 percent, without a significant difference; complications occurred on average in 6.8 percent of short implants and in 32.8 percent of long implants, which mostly needed grafting. The statement does, however, point to possibly more losses of short implants over time.
- Narrow-diameter implants: according to the ITI they can reduce the need for lateral grafting but have a higher risk of fracture; see mini dental implants.
The 2009 Cochrane review sees short implants in a shrunken lower jaw as possibly a better option than building up height. When height is missing at the back of the upper jaw because of the sinus, a sinus lift is the suitable procedure.
How long until the implant, and what does that mean for your trip?
According to Cambridge University Hospitals, blocks heal for 4 to 6 months before the implant is placed. Cleveland Clinic gives at least three months for a dental bone graft to heal and nine to 12 months for large grafts, and advises having the implant placed within six to 12 months once the graft has healed, because otherwise it may shrink. According to Guy’s and St Thomas’, whether the block has healed is assessed at a check-up, and most people can return to work 1 to 2 days after a graft with bone from the jaw.
For patients travelling from abroad, a block graft means more than one stay, because healing periods lie between the block, the implant and the teeth; the number of stays is set out in your written treatment and cost plan. Book your flights only once the plan is fixed; the advice on flying after a bone graft is in healing after a bone graft, the effect on your stays in how many days in Türkiye for dental implants.
Which options do we consider at Rönesans when bone is missing?
At our clinic in Serdivan, bone width and height and the distance to the nerve canal and the sinus are assessed in three dimensions on a CBCT scan. We carry out bone grafting and sinus lifts at the clinic, under general anaesthetic if needed. Whether a bone block, grafting with a membrane or a different implant solution suits you, and where the bone would come from, is assessed at the examination.
Before treatment begins you receive a written treatment and cost plan listing the procedures for each tooth and the number of stays; transfer from Istanbul and accommodation in Sapanca are included in the treatment price. For a preliminary assessment, send us existing X-rays on WhatsApp at +90 532 363 49 54; the implant procedure is described on our dental implants page.