Fate of monocortical bone blocks grafted in the human maxilla: a histological and histomorphometric study

Abstract

Local bone defects in the anterior maxilla are commonly grafted with monocortical blocks of autologous bone in order to restore the defect site prior to the placement of dental implants. Increasing evidence suggests that osteocytes are involved in the control of bone remodelling and thus may be important for optimalisation of bone structure around implants, and thus for implant osseointegration. However, it is not well known whether osteocytes will survive when bone blocks are grafted into defects. We grafted 19 patients with monocortical bone blocks derived from the symphysis, to the defect site in the maxillary alveolar process. The bone grafts were left to heal for times varying from 2.5 to 7 months. During implant installation, bone biopsies were removed using a trephine burr, and processed for hard tissue histology. Bone histology and histomorphometry were then carried out in order to gain insight into the density, viability and remodelling of the graft. Clinically, all the bone grafts were successful, with no implant failures, and little resorption was seen. Histologically, bone volume expressed as percentage of tissue volume at the implant site varied from 27% to 57% with an overall average of 41%. Bone fields with empty osteocyte lacunae were observed and measured. The amount of this so-called nonvital bone (NVB) varied between 1% and 34% of the total tissue volume. The amount of NVB decreased significantly with the time of healing. The data suggest that the majority of the osteocytes of the monocortical bone do not survive grafting. The results indicate that the NVB is progressively remodelled into new vital bone 7 months after grafting.

Sinus Floor Augmentation Surgery Using Autologous Bone Grafts from Various Donor Sites: A Meta-Analysis of the Total Bone Volume

“…31,40,41 Zerbo et al performed sinus augmentation surgery using monocortical blocks of autologous chin bone to allow dental implant placement. 19 As a result from biopsies taken at 2.5 and 7 months, the amount of nonvital bone decreased significantly with the time of healing, as it was progressively remodeled into new bone. 19 Zijderveld et al observed predominantly lamellar bone after a healing period of 6 months.…”

“…19 As a result from biopsies taken at 2.5 and 7 months, the amount of nonvital bone decreased significantly with the time of healing, as it was progressively remodeled into new bone. 19 Zijderveld et al observed predominantly lamellar bone after a healing period of 6 months. 33 Lorenzetti et al performed unilateral augmentation with bone blocks or particulated bone originating from the chin.…”

“…In all subgroups, a collagen barrier membrane was placed over the graft according to the principal of guided bone regeneration. [19][20][21][22] Further, Peleg et al 20 described the use of lypophilized duramater for such a purpose. Core biopsies were obtained after a healing period of 3-6 months with a mean TBV of 31.5-70%.…”

“…9,45 Surprisingly, this could not be confirmed by meta-analysis of the four selected papers. [19][20][21][22] Particulated and block grafting After statistical analysis, particulation of the bone graft seems to lead to a significantly lower amount of TBV, where there is no such evidence for bone blocks. In literature, it is reported that up to 33% of the autologous bone graft can resorb during the initial 6 months after sinus floor augmentation surgery.…”

“…9 For example, some studies advise to apply a resorbable or nonresorbable barrier membrane over the sinus graft osteotomy site. [19][20][21][22] Till now, no studies have been published that evaluated histological and histomorphometric data from a large amount of patients inventorying these variables. To answer the question as to which approach is the best in using autologous bone grafts after sinus floor augmentation surgery, a metaanalysis was conducted.…”