Autogenous bone graft harvesting

BONE HARVESTING FOR LOCALISED ALVEOLAR RIDGE DEFECTS
RAKESH CHANDRAN

• Localized alveolar ridge defect is intended to refer to a volumetric deficit of limited
extent in bone and soft tissue within the alveolar process.
• Classified according to defect expanse as a one-, two-, three-, or four-tooth defect.
Localized alveolar ridge defect
Studer et al 1997. Adjustment of localized alveolar ridge defects by soft tissue transplantation to improve mucogingival
esthetics: a proposal for clinical classification and an evaluation of procedures. Quintessence Int.

Bone blocks can be processed in a bone mill to obtain particulate grafts
Tibia grafts can be performed in an outpatient setting
Indication for extraoral bone grafts
Marx & Stevens 2010. Atlas of Oral and Extraoral Bone Harvesting. Quintessence Pub
Site Indication
Tibia 5 – 40 mL uncompressed cancellous marrow
Anterior ilium 30 – 50 mL of corticocancellous marrow
1- 5 cm corticocancellous bone block
Posterior ilium 40 – 120 mL uncompressed cancellous marrow
4 – 12 cm corticocancellous bone block
Cranial bone corticocancellous bone block (onlay graft) for midface, orbital,
zygomatic and nasal reconstructions

Posterior IliumAnterior Ilium
CraniumRib

Bone blocks can be processed in a bone mill to obtain particulate grafts
Greatest volume and greatest volume of cortical bone
Ramus> Chin
Greatest volume of cancellous bone
Chin> Ramus
Comparison of intraoral sites
Stern and Barzani 2015. Autogenous Bone Harvest for Implant Reconstruction. Dent Clin N Am
Carlson and Marx 1996. Mandibular Reconstruction Using Cancellous Cellular Bone Grafts. J Oral Maxillofac Surg
Nkenke and Neukam 2014. Autogenous bone harvesting and grafting in advanced jaw resorption: Morbidity, resorption
and implant survival. Eur J Oral Implantol
Site Indication
Chin 0.5 X 1.5 X 6 cm corticocancellous bone block
Mandibular ramus 0.4 X 3 X 5 cm mostly cortical bone block, J graft (thin)
Maxillary tuberosity 1 -3 mL cancellous marrow

• Proximity to recipient region
• Possibility of simultaneous graft
• Same embryonic origin- decreased resorption
Benefits of oral bone harvesting

Development of any given bone happens along one of two general pathways:
1. Endochondral ossification: bone replaces a hyaline cartilage precursor (long bones
such as tibia, fibula, femur and iliac crest)
2. Intramembranous ossification: direct mineralization of the organic matrix without
cartilage intermediate (bones of the cranio-facial complex with limited exception e.g.
condylar process)
Membranous origin vs cartilaginous origin
Faverani et al 2014. Surgical techniques for maxillary bone grafting – literature review. Rev. Col. Bras. Cir.

• Comparative studies of craniofacial reconstructions in animals and man appears to
show that intramembranous bone grafts tend to maintain their volume whereas
endochondral grafts are associated with delayed, sometimes dramatic resorption and
the associated implant success ranges between 25 – 86% (Jensen et al 2009).
• Membranous bone is superior to enchondral bone in maintaining volume in the initial
phase following the augmentation procedure (Nkenke and Neukam 2014).
• For the bone, after reaching the embryonic ossification process, is “bone tissue”, with
its unique characteristics, be it more cortical or more medullary. Thus is perhaps
associated more with the rate of resorption of the different donor sites as opposed to
the origin of the bone (Faverani et al 2014).
Membranous origin vs cartilaginous origin
Jensen et al. 1990. Reconstruction of the severely resorbed maxilla with bone grafting and osseointegrated implants: A
preliminary report. J Oral Maxillofac Surg.
Faverani et al 2014. Surgical techniques for maxillary bone grafting – literature review. Rev. Col. Bras. Cir.

• Horizontal ridge augmentation
• Vertical ridge augmentation
• Sinus elevation procedures
• Ridge preservation
• Dental implant salvage
Utilization of bone grafting in implantology

Autografts are the gold standard
Properties of various grafting materials
Site Osteconductive Osteoinductive Osteogenic
alloplasts ✓
xenografts ✓
allograft ✓
recombinant human BMP ✓
autografts ✓ ✓ ✓

2 conflicting theories of bone graft healing
• Osteoblastic theory- based on the belief that bone marrow and the periosteum
survived implantation and produced bone.
• Induction theory- proposed that the entire graft underwent an aseptic necrosis
and was replaced (creeping substitution) by bone produced by the connective
tissue stem cells of the host–recipient bed or host–bone ends. Bone necrosis was
linked with new bone formation.
It is now known that the osteoblastic and induction theories of cancellous bone are not
mutually exclusive. Current concept of cancellous cellular bone graft healing involves a
2-phased theory.
Graft healing
Carlson and Marx 1996. Mandibular Reconstruction Using Cancellous Cellular Bone Grafts. J Oral Maxillofac Surg
McAllister and Haghighat 2007. Bone Augmentation Techniques. J Periodontol.

• Cortical bone does not possess a high concentration of osteocompetent cells;
therefore, maintenance of viable osteoblasts or osteoprogenitor cells becomes
difficult.
• Revascularization (McAllister and Haghighat 2007)
cortical bone autografts< corticocancellous block grafts < particulate autografts
• Aggressive recipient bed preparation with decortication, intramarrow penetration, and
inlay shaping also has been supported to improve revascularization.
• Cortical bone, owing to its high lamellar concentration, has little surface area and is
more susceptible to infection.
• It is absolutely crucial to maintain the soft tissue coverage over the graft. In the event
that soft tissue cover is compromised, graft viability will be lost.
• The stabilization and intimate contact of these block grafts to the recipient bed has
been considered crucial to a successful outcome. This can be achieved with the use of
bone fixation screws or the simultaneous placement of dental implants.
Graft healing: cortical bone
McAllister and Haghighat 2007. Bone Augmentation Techniques. J Periodontol.

1. Choose the least morbid harvest site, and harvest the graft with least morbidity
2. Graft into a vascular tissue bed
Must imbibe nutrients from the recipient tissue bed for the first 3-5 days-
Plasmatic circulation. Capillary ingrowth begins during day 3 and is complete by
day 21
3. Graft into an infection-free and contamination-free tissue bed
Because the graft is not completely vascularised for 14-21 days, immunoglobulins
and WBC have little access to the graft site, making the graft prone to infection
4. Ensure the stability of the graft for at least 21 days
The capillaries sprouting are only 6-8 μm in diameter and are not able to resist the
compressive or shear forces.
Principles of autogenous bone harvesting

Local apical infection
Metabolic bone disease (osteopetrosis, BRONJ, osteogenesis imperfecta etc.)
pyknodystosis)
Radiation therapy
Cysts or tumors
IV or oral bisphosphonate use
Long term or current methotrexate or steroid medications
Smoking?
General contraindications or cautions

• “use of CT in combination with suitable software is a good method for determining the
dimensions and surface of possible bone grafts.
• Furthermore, this is a more accurate method than that used by previous studies that
involved the use of calipers or measured displaced saline for evaluation of the graft
size.
• it is possible to perform planning of the implant position at the same time as making
an analysis of the jaw for potential donor areas, by using a corresponding software
program (Pro Plan 3.0)”
Evaluation of donor sites
Möhlhenrich et al 2015. Three-dimensional evaluation of the different donor sites of the mandible for autologous bone
grafts. Clin Oral Invest

Harvesting techniques for particulate autogenous bone

1. cortico-cancellous block grafts harvested with a 6-mm trephine and ground to
particulated bone chips in a bone mill
2. bone chips harvested with a sharp bone scraper
3. bone particles collected from the aspirator with a bone trap filter during the
preparation of the osteotomy
4. bone particles harvested with a piezo-surgery device
Harvesting techniques for particulate autogenous bone
Miron et al 2011. Osteogenic Potential of Autogenous Bone Grafts Harvested with Four Different Surgical Techniques. J
Dent Res.
Bone mill Bone scraper Bone trap filter

• Safescrapers, a specially designed cortical bone collector.
• Safescraper can harvest bone chips up to 5 ml in length in a single scoop
• Particulate bone collected with the bone mill or by rotating electrical instruments
appears to reduce the amount of viable bone cells supplied and impoverish the quality
of the collected bone.
• Bone can be collected during implant surgery with bone trap filters, but they need an
implant site and may incur microbial contamination.
Safescrapers
Zaffe and D’Avenia 2007. A novel bone scraper for intraoral harvesting: a device for filling small bone defects. Clin. Oral
Impl. Res

Bone harvesting: Maxillary tuberosity

Bone harvesting from the maxillary tuberosity

Bone harvesting from the maxillary tuberosity- complications

• Autogenous bone blocks result in higher gains in ridge height and width compared to
particulate grafts
Consensus statements: autogenous bone block vs particulate bone in treating localized
alveolar ridge defects
Chen et al 2009. Consensus statements and recommended clinical procedures regarding surgical techniques. Int J Oral
Maxillofac Implants

Corticocancellous bone graft of limited size (1.5 x 6 cm) if taken across the midline
Cortococancellous particulate graft (5 to 7mL) if processed in a bone mill
Bone harvesting from the chin-indications

Bone harvesting from the chin- anatomy

McDonnell et al 1994. The mandibular lingual foramen: a consistent arterial foramen in the middle of the mandible. J.
Anat.
Mandibular lingual foramen and lingual plexus

• 701 tapered fissure bur/ piezo
• Saline/ PRP/ aluminium foil
• Round bur/ bone file
• Bone substitutes: allogenic/ xenograft or tricalcium phosphate hydroxyapatite cements
• Collagen fleece
• elastic tape (microfoam tape)
• Cautery/ bone wax/ epinephrine or thrombin-soaked sponges.
Bone harvesting from the chin- preparation

Bone harvesting from the chin

A classic chin dressing—that is, placement of
fluffed sponges or cotton rolls over the chin
prominence and mentolabial crease followed
by elastic tape (microfoam tape is best) with
crossover slits—is recommended.
These crossover slits at the end of the elastic
tape allows the inferior segment and superior
segments to overlap, which applies a greater
adaptation to the chin and makes it a true
pressure dressing.
Bone harvesting from the chin- dressing

• Non abrasive soft diet for 1 week
• Dressing removed after 5 days
• Ice not recommended as the dressing prevents benefits
Bone harvesting from the chin- post operative

• Rare
• most common-paresthesia of the lower lip vermillion
• Damage to apices of incisor or canine roots
• Bleeding- intraoperative- cautery (if brisk- bone wax –always keep in stock)- or
surgical, or temporary packing with epinephrine or thrombin-soaked sponges.
• Assure the patient that a hematoma or ecchymosis may occur (esp fair skin)
• If site worsen with infection- after even antibiotics and culture- after 3 days- wound
exploration for cultures, debridement, and irrigation with 0.12% chlorhexidine is
recommended.
Bone harvesting from the chin- complications

Bone harvesting: Mandibular ramus

A thin cortical block of limited size (0.4 X 3 X 5cm)
Possibility of harvesting from both sides to obtain double the volume
Utilization
• Horizontal ridge augmentation in the anterior maxilla that overlaps onto the ridge
crest—known as a ‘J’ graft
• General horizontal or vertical ridge augmentation of either the maxillary or
mandibular ridge as site preparation for dental implants
Limitations
• The graft is almost 100% cortical bone.
Bone harvesting from the mandibular ramus- indications and utilization

Bone harvesting from the mandibular ramus- anatomy

• Rare
• Inferior alveolar nerve injury- avoid by concluding the innermost part of the
osteotomy 5mm above the radiographic presentation of the mandibular canal, also
instrument against the inner cortical wall allows a layer of trabecular bone between
graft and nerve
• If damage occurs- immediate microneural reanastamosis/ epineural nerve repair or
refer for secondary repair to be done within 3 months
• After 3 months, nerve regeneration rapidly declines up to 6 months after which one
cannot expect much nerve regeneration with a microneural repair.
• If no nerve injury is observed but post operative paresthesia of the lip and chin region,
best avoid re-entry and allow the nerve to recover. Maximum return of sensation is
complete within 6 to 9 months
• Lingual nerve injury
• Hematoma
• Wound infection
• Fracture
Complications

• Mandibular bone blocks (external oblique ridge), which consist primarily of cortical
bone and a low percentage of cancellous bone, are more resistant to revascularization
and consequently may have poor regeneration potential. For this reason, the
harvested thick bone blocks were split into two thin bone blocks with the diamond
disk according to the split bone block technique of the biologic concept of grafting
procedures.
• Splitting the thick blocks into two thin blocks not only increases the number of bone
blocks, offering the possibility to graft more surfaces in different forms, but also
improves revascularization and regeneration.
• The thin blocks were stabilized at the recipient site with microscrews, and any gaps
were filled with autogenous bone chips harvested from the donor site with a bone
scraper.
• No biomaterials or membranes are used.
• This technique with pure autogenous bone, which has been used for 20 years, has
shown a high success rate.
Khoury technique/ split bone block technique/ shell technique
Khoury and Hanser 2015. Mandibular Bone Block Harvesting from the Retromolar Region: A 10-Year Prospective
Clinical Study. Int J Oral Maxillofac Implants

Khoury technique- Micro-Saw®
• The MicroSaw® consists of a thin diamond disk with a diameter of 8 mm that is
mounted on an angle piece or a hand piece, with a disk protector to prevent any
injuries of the soft tissue.
• Three osteotomies are performed with the diamond disk: two proximo-vertical and
one baso-horizontal. The final osteotomy, on the occlusal crestal site, is achieved with
a thin, 1-mm drill bur because of poor access to this site with the MicroSaw

• Donor sites, treated with collagen fleece, usually healed without re-formation of the
lamina dura of the external oblique line.
• Regeneration of the donor site was nearly complete, if one of the blocks left after
grafting was replaced at its donor site. This was shown clinically within 6 to 40 months
when reentry of the harvested area was performed and radiologically within 18 to 36
months when a CBCT scan was made.
• Because the diamond disk in the MicroSaw is thin, it makes a precise osteotomy, and
in 47.1% of cases, half bone blocks were placed back into the donor site within the
contour of the external oblique line over the collagen fleece, without the need for a
stabilizing screw. The remaining 52.9% of repositioned bone blocks were stabilized
with a small screw. In all cases, a well regenerated and healed external oblique ridge
was found.
• The complete regeneration of the donor site allows for future re-harvesting of a well
dimensioned bone block if needed for another bone augmentation procedure
Khoury technique- modified

Harvesting the bone shells and extraoral trimming with a cutting wheel is very technique-
sensitive.
Additional harvesting of bone chips is also necessary.
Therefore, the authors modified and simplified this technique.
Modified shell technique
Stimmelmayr et al 2012. Use of a modified shell technique for three-dimensional bone grafting: description of a
technique. Aust Dent J

Stimmelmayr et al 2012. Use of a modified shell technique for three-dimensional bone grafting: description of a
technique. Aust Dent J

Palatal bone block
Gluckman et al 2016. The Palatal Bone Block Graft for Onlay Grafting Combined with Maxillary Implant Placement: A
Case Series. Int J Periodontics Restorative Dent.

Saline
• Preserves more than 95% of graft cell viability for at least 4 hours
Platelet rich plasma
• Growth factors in PRP bind to cell membranes and act to upregulate
osteocompetent cell proliferations during this time their cell adhesion molecules
enhance the matrix of the graft by connecting the mineral components
Aluminium foil?
• foil protects the graft from airborne bacteria and fungi spores, and retains
moisture so that the graft does not dry out as quickly.
Never water
• Due to an osmotic gradient, the hypotonicity of water causes the cells to swell and
burst
Storage of harvested bone

• The symphysis has lower associated morbidity compared with ramus (Stern and
Barzani 2015).
• The mandibular ramus was preferred by the patients. Patients’ acceptance of chin
bone harvesting was low. Patients even preferred iliac crest bone harvesting over bone
harvesting from the chin, although this distant donor site required general anaesthesia
and a hospital stay (Nkenke and Neukam 2014).
COMPARISON OF MORBIDITY OF ORAL SITES

• Bone harvesting from the mental symphysis is associated with relevant morbidity, and
the quantity of available bone is frequently limited. Neural damage to the incisal nerve
occurs frequently. Therefore, the mental symphysis should not be the first choice for
harvesting.
• Bone harvesting from the maxillary tuberosity is followed by low morbidity but is not
well documented. The quality and quantity of available bone is often poor. Indications
are limited to reconstruction of small defects.
• Bone harvesting from the mandibular ramus offers good quality and quantity of
available bone, due to the possibility of harvesting from both sides.
Consensus statements
Maxillofac Implants

Among all of the BMPs that were examined, BMP-2, 6, and 9 may be the most potent
agents to induce osteoblast lineage-specific differentiation of mesenchymal progenitor
cells while most BMPs can effectively promote the terminal differentiation of committed
osteoblastic precursors and osteoblasts. It is conceivable that combinations of BMPs also
may be able to induce osteogenesis in early mesenchymal stem cells.
Osteogenic hierarchy of BMPs
Cheng et al 2003. Osteogenic Activity of 14 types of human BMPs. JBJS

1. RhBMP2
• rhBMP2 100% active (filter sterilized)
• 1.5mg/cc
2. Absorbable Collagen sponge
• Type 1 bovine collagen sponge
• Binds BMP to localize concentration
• Over 20 years of clinical use
INFUSE Bone graft (Rh-BMP2/ACS)
Wiki

INFUSE Bone graft (Rh-BMP2/ACS) kit
INFUSE BONE GRAFT. MEDTRONIC. www.infusebonegraft.com. Assessed 12 Sep2016
Total graft
volume 0.7cc
Sterile water for injection Sterile rhBMP-2 Sterile absorbable
collagen sponge
The sterile water is drawn up into the supplied syringe and injected into the vial of
powdered rhBMP-2. Allow 5 minutes for complete dissolution of rhBMP-2. After 5
minutes, the solution is drawn up and added to the acellular collagen sponge a drop at a
time until the entire sponge/sponges are wetted. Wait 15 minutes.

• Placed into a bony defect, the bound BMP in the acellular collagen sponge is
chemotactic to stem cells and preosteoblasts. As these cells migrate into the sponge,
they undergo proliferation and differentiation into osteoblasts, which then synthesize
osteoid. Once this process is initiated, the osteoid will undergo the standard
resorption-remodeling cycle of bone to a mature ossicle in 6 months
Mechanisms of Action

• tissue healing is limited by cell capabilities during the described phases of bone
healing with cell recruitment, chemotaxis, differentiation, and specific tissue matrix
production and cannot be speeded beyond biological limits by external growth factors.
• application of growth factors and their influence on adult and embryonic stem cells
and differentiated tissues bears the risk of carcinogenic transformation
Concerns with regard to rhBMP2/ACS
Draenert et al 2013. Vertical bone augmentation procedures: Basics and techniques in dental implantology. J Biomed
Mater Res Part A 2014

Nkenke and Neukam 2014
• 24 studies were included in the review
• The data on implant survival and success do not allow the identification of a bone graft
that is associated with a significant improvement of these parameters. Even with
complete resorption of the grafted bone, an implant survival rate of 100% can be
reached. It seems that the type of bone graft has only a limited influence on implant
survival and success.
• Instead, confounders like the type of implant installed seem to have a major influence
on implant survival and success.
IMPLANT SURVIVAL AND SUCCESS

• Autogenous bone blocks result in higher gains in ridge height and width compared to
particulate grafts.
• Accurate modeling and stabilization of the graft with screws, and tension-free primary
closure of the overlying flaps, are fundamental for the success of the procedure.
• Overcorrection of the defect is recommended to compensate for the potential risk of
bone resorption.
• Coverage of the bone grafts with a low-resorption—rate xenograft/alloplastic material,
with or without a membrane, may be indicated to reduce bone resorption.
• Use of membranes does not significantly influence the outcome.
• The predictability of vertical ridge augmentation is substantially lower and the
complication rate substantially higher than with horizontal ridge augmentation
procedures.
• Survival rates of implants placed in augmented alveolar ridges are high.
Conclusion- Consensus statements
Maxillofac Implants

To compare volumetric changes after sinus augmentation of completely edentulous
maxillae with either autogenous or allogeneic fresh-frozen bone particles.
MATERIALS AND METHODS:
This split-mouth study in patients who required bilateral sinus grafting used autograft
particles for one sinus and allograft particles for the contralateral sinus. The grafted
sinuses were left to heal for 6 months prior to implant insertion. All patients underwent
four computed tomography scans: prior to augmentation and 1 week, 6 months, and 12
months after grafting. Computer software was used to analyze bone graft volume in each
scan.
Maxillary Sinus Grafting with Autograft Versus Fresh-Frozen Allograft
Xavier et al 2015. Maxillary Sinus Grafting with Autograft Versus Fresh-Frozen Allograft: A Split-Mouth Evaluation of
Bone Volume Dynamics. Int J Oral Maxillofac Implants

RESULTS:
Fifteen patients (8 men, 7 women) with a mean age of 54 ± 5 years (range, 48 to 60
years) took part and underwent 30 sinus augmentation procedures. Mean autograft and
allograft volumes were not statistically significantly different at each time point (1 week:
2.01 ± 0.43 cm³ vs 2.46 ± 0.79 cm³; 6 months: 1.53 ± 0.49 cm³ vs 1.75 ± 0.64 cm³; and 12
months: 1.38 ± 0.43 cm³ vs 1.59 ± 0.56 cm³, respectively). Mean volumetric reductions of
31.35% and 35.36% (23.9% and 29.9% in the 6 months prior to implant insertion,
followed by an additional 9% and 9% in the following 6 months), relative to 1 week
postgrafting, were noted for the autograft and allograft groups, respectively, after 12
months.
CONCLUSION:
On the basis of this split-mouth study of 15 patients, there was no statistically significant
volumetric difference after 12 months between the use of autograft or allografts for sinus
augmentation. Fresh-frozen bone allograft may serve as an alternative that avoids the
morbidity associated with autograft harvesting.
Maxillary Sinus Grafting with Autograft Versus Fresh-Frozen Allograft
Xavier et al 2015. Maxillary Sinus Grafting with Autograft Versus Fresh-Frozen Allograft: A Split-Mouth Evaluation of
Bone Volume Dynamics. Int J Oral Maxillofac Implants

Literature regarding the outcome of maxillary sinus floor elevation to create sufficient
bone fraction to enable implant placement was systematically reviewed. Bone fraction
and implant survival rate were assessed to determine whether grafting material or
applied growth factor affected bone fraction. Trials where sinus floor elevations with
autogenous bone (controls) were compared with autogenous bone combined with
growth factors or bone substitutes, or solely with bone substitutes (test groups) were
identified; 12 of 1124 fulfilled all inclusion criteria. Meta-analyses comparing the bone
fraction after applying: autogenous bone; autologous bone with growth factors (platelet
rich plasma); or autogenous bone and bone substitutes (bovine hydroxyapatite, bioactive
glass, corticocancellous pig bone) revealed no significant differences in bone formation
after 5 months.
Maxillary sinus lift with solely autogenous bone compared to a combination of
autogenous bone and growth factors or (solely) bone substitutes.
Rickert et al 2012. Maxillary sinus lift with solely autogenous bone compared to a combination of autogenous bone and
growth factors or (solely) bone substitutes. A systematic review. Int J Oral Maxillofac Implants

A significantly higher bone fraction was found in the autogenous bone group compared
to the sole use of β-tricalciumphosphate (P=0.036). The one-year overall implant survival
rate showed no significant difference between implants. Bone substitutes combined with
autogenous bone provide a reliable alternative for autogenous bone as sole grafting
material to reconstruct maxillary sinus bony deficiencies, for supporting dental implants
after 5 months. Adding growth factors (platelet rich plasma) to grafting material and the
sole use of β-tricalciumphosphate did not promote bone formation.
Maxillary sinus lift with solely autogenous bone compared to a combination of
autogenous bone and growth factors or (solely) bone substitutes.
Rickert et al 2012. Maxillary sinus lift with solely autogenous bone compared to a combination of autogenous bone and
growth factors or (solely) bone substitutes. A systematic review. Int J Oral Maxillofac Implants

Autogenous bone graft harvesting

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