Maxilla augmentation with calvarial bone or iliac crest bone: a comparison

In edentulous patients the bone of the upper and lower jaw resorb during
several years. When a substantial amount of bone is lost, the patient cannot
wear a denture satisfactorily, because the denture is not supported anymore by
enough bone. A solution to this problem is the placement of dental implants on
which the denture can be fixed. However, there is often insufficient bone
volume left to insert the dental implants. Therefore, bone needs to be
transplanted to the upper jaw first. After the bone graft procedure a time of 4
- 6 months is generally taken ino account for the bone to heal. After healing,
the dental impants can be inserted in the upper jaw (=maxilla). It must be
noted however, that transplanted bone tends to resorb in volume during these
months of healing, making it difficult to predict the final outcome.
In the University Medical Centre Groningen, bone harvested from the anterior
iliac crest is taken to augment (= transplant to) the maxilla. In
Emmen/Stadskanaal, bone is harvested from the calvarium (= skull). In a pilot
study we conducted, it seemed that patients operated on the skull had much
lower pain-levels of the donor site postoperatively, when compared to patients
where bone was harvested from the iliac crest. Also, it was interesting to
observe that the calvarial bone tend to show less resorption over time than
iliac crest bone.
This is an important observation, since calvarial bone has therefore the
potential to be a more predictable bone source than iliac crest bone.
Therefore we decided to conduct a prospective randomised clincal study
comparing these two donor sites (calvarium and iliac crest) with respect to
bone volume changes and bone formation. Also morbidity (average pain and
complication rate) will be measured for both treatment modalities.

Therefore we decided to conduct a prospective randomised clincal study
comparing these two donor sites (calvarium and iliac crest) with respect to
bone volume changes and bone formation.


Primary Objective: to know what the changes in bone volume are of iliac crest
grafts and calvarial bone grafts during 4 months of healing

Secondary Objective(s): to know if there is a difference in bone formation at 4
months in the iliac crest graft and in the calvarial bone graft

Thrird objectives: to know the average pain and complication rate of both
groups

Prospective randomised trial

For the harvestig of iliac crest bone, the risks/complications are: chronic
pain at the donor site, neuropraxia of the lateral femoral nerve, periotoneal
perforation, bleeding, infection, fracture, wound dehiscence, hyperthrophic
scars.
The overall risk is 19% according to a systematic review; Dimitrious 2011.

For harvesting of calvarial bone the risks are: bleeding, dural tear,
infection, haematoma. The risk is very low and managable (0.25%), Tessier 2005.

For the augmentation of the maxilla the risks are: perforation of the sinus
maxillary membrane, bone resorption, wound dehiscence, infection, bleeding. The
risks are low and managable (<2%), Mertens 2011.

The biopsy that is taken during surgery only comprises <1 % of the bone volume.
It is not reasonable to assume that this procedure adds any additional risk
than the normal surgical risks.

The risk for an allergic reaction to Tetracycline is estimated at 0.5% (Macy
2009). The Tetracycline to label the bone for histomorphometric measurements is
taken in a short course of two times for two days at a low dose, so the risk
seems lower.