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Introduction:
In maxillofacial surgery, there is always a need to fill the
bony defects following surgery. So bone grafts are often
necessary to provide support, fill voids, and enhance
biologic repair of skeletal defects. In the orofacial region
various types of bone grafts have been used that includes-
autografts, allografts, xenografts and alloplastic materials.

Radicular cyst is the most common type of inflammatory
odontogenic cysts of the jaws, which comprises nearly
65%-70% of all jaw cysts1 and dentigerous cyst is the
most common type of developmental odontogenic cyst of
the jaw which is nearly 15%-18% of all jaw cysts.
Following enucleation of a cyst defects smaller than 2 cm
in diameter can be closed primarily and normally fill up
with blood clot. But in case of large defect clot breakdown
and infection are more likely to occur in a large
haematoma. So it is considered as good technique to
obliterate the dead space of a sizable defect by packing
the cavity with bone or a bone substitute. In the large

Bone Grafts in Jaw Cysts- Hydroxyapatite & Allogenic Bone – A
Comparative Study
Showkat Mamun, Mahmuda Akhter, Motiur Rahman Molla
Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Bangabandhu Sheikh Mujib Medical University.

Abstract:
Background:  Auto bone is the gold standard in bone grafting. However, the morbidity and additional surgical time
associated with its collection, as well as the limited supply, have stimulated the search for substitutes. Allograft is more
limited than autograft because it yields more variable clinical results. Composite synthetic grafts offer an alternative
because Hydroxyapatite is chemically identical to the inorganic matrix of living bones and it can be processed synthetically.
The intent was to evaluate these two graft materials for clinical use and to provide an insight on the different grafting
strategies to enhance bone formation. Objective: To find out the bone healing process and the prognostic value for the
patient using hydroxyapatite alloplastic material and allogenic bone graft. Method: Total 28 patients were included in
the study after the clinical and radiological evaluation where 14 cases were treated with allogenic-bone graft and rest 14
cases were treated with hydroxyapatite alloplastic material after enucleation of the cystic lesion in random manner. The
integration of hydroxyapatite and allogenic bone was assessed with postoperative lesion diameter, trabecular pattern,
histopathological and scintigraphic examination of the successful graft cases. Statistical analysis was carried out by
‘unpaired T test’ and ‘Chi square’ test.  Result: The radiological, histopathological and scintigraphical outcome of the
patients treated with hydroxyaptite granule bone graft were clinically and statistically superior in comparison with those
who were treated with allogenic bone graft. Conclusion: This safe and osteoconductive hydroxyapatite appears suitable
for filling bone defects and bone cavities, showing less resorption and a rapid osseous integration.

Key word: Hydroxyapatite, allogenic bone, scintigraphy, radiology, histopathology.

[BSMMU J 2009; 2(1): 25-30]

Address for correspondence: Dr. Showkat Mamun, Department of
Oral and Maxillofacial Surgery, Faculty of Dentistry, Bangabandhu
Sheikh Mujib Medical University. Email: mamunshowkat@gmail.com

surgical cavity, residual contour defects due to collapse
of soft tissue into the cavity can be eliminated and the
repair process appears clinically and roentgenographically to
proceed more rapidly than after simple surgical excision 2.

Although autogenous bone is the gold standard that all
alternatives must meet or exceed, autograft has limitations,
including donor site morbidity, inadequate amount, and
inappropriate form 3-5. These limitations have prompted
increasing interest in alternative to bone grafts.
Consequently, significant efforts are being made to develop
ideal bone graft substitutes. 6
Synthetic ceramics are readily available and are without
infectious or immunogenic potential.  They reduce patient
morbidity significantly by reducing the need for a second
operative site. Calcium phosphates (CaP) account for most
ceramic-based bone graft substitutes currently available.
Hydroxyapatite (HA) is the most used polycrystalline
calcium phosphate ceramic mineral as an artificial bone
graft substitute. It is biocompatible, highly resistant to
stress forces, nontoxic and noncarcinogenic. It has marked
osteoconductive and osteoinductive properties that lead
to the regeneration of lamellar bone within 4 to 10 months



35

of implantation. This characteristic is exploited in many
surgical areas (orthopedics, maxillofacial surgery,
dentistry, plastic surgery and neurosurgery). It also has
been used to coat other materials to increase their stability
and osteointegration.

It has been used to reconstruct defects of the jaw and other
facial bones, to obliterate mastoidectomy cavities and to
reconstruct the ossicular chain and wall of the outer ear
canal. Other uses of Hydroxyapatite range from
augmenting atrophic alveolar ridges to repairing long-bone
defects, ununited fractures, middle ear prostheses, spinal
fusions, and cranioplasties.

Unfortunately, the major drawbacks to the use of CaP
ceramics are their adverse mechanical properties. They
are brittle, have low impact resistance, and have low tensile
strength; consequently, they fail when used in a structural
capacity. The lack of viscous flow is a serious limitation
for CPCs. Despite this problem, some researchers tried
injecting CPCs in paste form. The most notable among
such reports is that of Constantz et al 7. Its tendency for
granular migration and incomplete resorption has become
a long-term problem 8.

Allogenic bone is another attractive source of bone grafting
material next to auto bone. Allogeneic bone, with variable
biologic properties, is available in many preparations:
frozen, freeze-dried, irradiated, or demineralized.
Transplantation of allogenic bone as a method of treatment
as various disorders of skeleton was started late decade of
19th century and 1st decade of 20th century. Freeze-dried
bone allograft was first introduced by United State Navy
tissue Bank in 1951 9.

Though allografts are attractive sources, there are several
problems encountered in using them, including resorbtion,
relative risk of disease transmission, immunogenicity, loss
of biologic and mechanical properties secondary to its
processing,  and non-availability world-wide due to
financial and religious concerns.

Bone Trabeculae are composed of thin radiopaque plates
and rods. To evaluate the trabecular pattern in a specific
area it is necessary to compare with the surrounding bony
trabeculae and some time with previous radiograph.

Scintigraphic images are obtained utilizing the intravenous
administration of a radiopharmaceutical, particularly
technetium-99m labeled diphosphonates. In an in vitro
binding assay, the competitive adsorption of technetium-
99m labeled diphosphonates to pure hydroxyapatite is
forty times greater than to pure organic bone matrix. Thus,
its uptake correlates well with the rate of mineralization

10. Harbert 11, mentioned that bone scintigraphy provides
a means of predicting graft failure before radiographic or
clinical changes become apparent and, thus, helping to
avoid a loss of surrounding bone from graft necrosis or
infection.

Thus the study is designed to evaluate the integration of
HA and allogenic bone as bone graft by assessment of
postoperative lesion diameter, trabecular pattern,
histopathological evaluation and scintigraphic assessment
of the graft to its future use with maxillofacial
reconstruction.

Method:
It was a prospective study conducted in the Department
of Oral and Maxillofacial Surgery, Bangabandhu Sheikh
Mujib Medical University between the period of July 2006
to June 2008. 28 patients were included in the study with
inclusion criteria of non infected cystic type of lesion
(Radicular and Dentigerous cyst), lesion size between 2
cm to 7 cm in diameter. Patients with any systemic bone
disease or diabetes, tuberculosis, rheumatic heart diseases
and renal failure, psychologically abnormal patients or
patients who had taken radiotherapy in the orofacial region
were excluded.

Total 28 patients were included in the study after the
clinical and radiological evaluation. Among them 14 cases
were treated with allogenic-bone graft and rest of the 14
cases were treated hydroxyapatite alloplastic material after
enucleation of the cystic lesion in random manner.

After all preoperative investigations and radiological
examination in selected cases were operated following
standard surgical procedure meticulously in sterile
environment under local anesthesia and sedation.
Enucleation of cyst was done with removal of all
granulation tissue. After enucleation of cyst bony cavity
was irrigated with diluted povidone iodine for the purpose
of debridment. Granules of hydroxyapatite or allobone
was placed on the surgical defect and wetted with patient
blood or saline solution followed by primary closure of
the wound. (Fig-1, Fig-2)

The wound was checked on the following day and
radiograph was done three days after operation. Sutures
were removed on seventh post operative day.

Assessment:
Observation of the diameter of the lesion – The final initial
radiological diameter was recorded at the 3rd post
operative day to get the exact extension of the lesion
because the surgical procedures have changed the
preoperative lesion diameter.

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Then the Initial diameter of the  lesion was measured and
follow-up was done for each patient  with occlusal view/
OPG or intraoral periapical view with the same
magnification, exposure time , Kv,  in the  same X ray
machine with the  same operator so that measurement of
lesion diameter  have the accurate result measured  with a
mm scale.

Each OPG was done by Cranex Base X (Finland)
panoramic dental X-ray machine with mA set to 10 and
KV set to 75 for each patient. Each occlusal view was
done with mA set to 100, KV set to 50 and exposure time
set to 0.10 sec from exactly the same distance and
angulation for each of the patient. For each periapical view
JYF -10 (China) X- ray machine is used with mA was set
to 10 , KV set to 55 and exposure time  was set to 0.80 sec
again with  maintaining the same distance and angulation.
The margin of the successful bone grafts showed less
sharpness than the immediate post operative margin in
each case after one month.

Observation of trabecular pattern of woven bone-
Trabecular pattern of woven bone with each patient was
evaluated visually by comparing the X-ray of the same
patient from two different focuses using a standard scale
with image processing software in collaboration with the
Department of Radiology and Imaging, Bangabandhu
Sheikh Mujib Medical University. . The first focus is from
the healthy portion of bone with normal trabecular pattern
and the second focus is from the intervented cystic defect
with the graft which has lost the normal trabecular pattern
or from the region of interest of the same patient assuming
100% trabecular pattern is present in the first focus and
comparing it with the region of interest.

Histopathological examination was done after six month
of operation. Few patients were randomly selected from
each group both Hydroxyapatite and allobone. Tissue
specimen was taken from all these cases  after reflecting
the mucoperiosteum at the previous lesion area to find
out the presence or absence of cementing line, osteoblast,
woven bone, fibrous and chronic inflammatory cell to
assess the quality of the graft material in the healed  lesion.
This was done in the department of Pathology, BSMMU
with their detailed pathological report.

Scintigram was done after six month of operation. Few
patients were randomly selected from both Hydroxyapatite
and allobone graft group. Three phase scan was done with
technetium- 99m labeled diphosphonates for each patient
to access the viability of bone graft or areas of increased
bone metabolism are evidence of good viability and appear
as areas of increased radiotracer uptake, namely “hot
spots”. Diminished or absent uptake are called “cold
spots”.

Data Analysis:
In the study different variables were analyzed in all
subjects including: age, sex, site of lesion, size of lesion,
cortical bone status, oral hygiene radiological findings
(Diameter of radiolucency and trabecular pattern after 1,
3 and 6 months), histologic examination of the cystic cavity
margin after 6 months of operation, scintigraphic findings
(Evaluation of tracer uptake after 6 months of operation)

All the data sheet of history and x-ray were collected and
analyzed scientifically and computer based statistical
analysis using SPSS software was carried out with
appropriate techniques and systems. Results were
presented as a detailed pathology report that includes high-
resolution digital photomicrographs with image processing
software. Data were analyzed statistically by ‘unpaired t
test’ and ‘ chi square’ test.

Results:
The mean diameter of lesion was 3.3±0.98 cm in group A
(with Hydroxyapatite bone graft) and 3.9±1.40 cm in group
B (with Allogenic bone graft) during preoperative period.
After 1 month the mean diameter declined and found
2.67±0.89 cm in group A and 2.80±0.99 cm in group B.
After 3 months the mean diameter further reduced and
found 1.92±0.63 cm in group A and 2.00±0.77 cm in group
B. Finally after 6 months the mean diameter was 0.96±0.23
cm in group A and 1.25±0.45 cm in group B. The difference
was statistically significant (p<0.05) after 6 months but
after 1 month and 3 months the difference was not
statistically significant (p>0.05) (Table-I).

Fig.-1: Surgical procedure of hydroxyapatite bone graft
in a cystic cavity.

Bone Grafts in Jaw Cysts- Hydroxyapatite & Allogenic Bone –  A Comparative Study Showkat Mamun et al

27



37

Fig.-2: Surgical procedure of allogenic bone graft in a
cystic cavity.

Fig. -3: Radicular cyst, treated with Hydroxyapatite bone
graft. Significant radiological improvement was
observed.

Fig.-4: Dentigerous cyst treated with freeze dried
allogenic bone graft. Significant radiological
improvement was not observed.

Preoperative view               Post operative view after 6 months

Fig.- 5: Patient treated with hydroxyapatite bone graft.
Under microscope with high magnification shows
osteoblastic activity and cementing line which indicates
woven bone formation.

Fig. -6: Patient treated with allogenic bone graft. Under
microscope with high magnification shows fibrous tissue
deposition and chronic inflammatory cell which indicates
no new bone formation.

Fig.-7: Patient treated with freeze dried allogenic bone
graft. Radionuclide bone scanning shows less tracer
uptake which indicates average osteoblastic activity.

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Table-I
Mean lesion diameter of the patients between two groups

Group-A Group-B
(n=14) (n=14) p value

Mean ±SD Mean ±SD
Preoperative 3.30 ±0.98 3.90 ±1.40 0.167 NS

After 1 month 2.67 ±0.89 2.80 ±0.99 0.725 NS

After 3 months 1.92 ±0.63 2.00 ±0.77 0.770 NS

After 6 months 0.96 ±0.23 1.25 ±0.45 0.039S

Group-A: With Hydroxyapatite bone graft
Group-B: With Allogenic bone graft
NS= Not significant, S= Significant,
 P value reached from unpaired t-test

Table-II
Distribution of the patients by management type and

incidence of infection.

Post operative Group-A Group-B
(n=14)  (n=14) p value

Infection number % number %

Infection occur 0 0.0 5 35.7

No infection 14 100.0 9 64.3 0.020S

Total 14 100 14 100

Group-A: With Hydroxyapatite bone graft
Group-B: With Allogenic bone graft
 S= Significant
 P value reached from Chi square test

Fig.-8: Patient treated with hydroxyapatite bone graft.
Radionuclide bone scanning shows increased tracer
uptake which indicates good osteoblastic activity.

Discussion:
It was found that in reducing the diameter of lesion with
hydroxyapatite bone grafts were both clinically and
radiologically better than allogenic bone graft (Fig-3). It
was supported by Zuev et al12. This observation was
concluded by them that the patients with hydroxapatite
bone graft showed better radiological outcome than their
allogenic counterparts. They also revealed the outcomes
of two groups, poorly defined in the initial few weeks but
in the later period like three months it was significant, this
result is very close to Schwartz et al. 13

Patients with hydroxapatite bone graft showed superior
trabecular pattern than the allogenic counterparts (Fig-4).
The difference of trabecular pattern between the two
groups started to amplify in the post operative period. The
difference was almost persistent throughout the period of
6 months, with gradual increasing tendency.

Histopathological slide was prepared from randomly
selected cases of both study and control group from same
site and procedure after six months of operation. According
to the histopathological findings the neo-osteogenetic
process was better in the hydroxyapatite group  (Fig. 5,
Fig. 6). Microscopic findings revealed that the graft was
seated in the duel process of osteoclastic and osteoblastic
activities with the ingrowths of capillaries. There was
marked cementing line which indicates deposition of
woven bone; on the other hand there was less definite
histological feature of active bone formation rather fibrous
deposition showed in allogenic bone group. Moreover the
infiltration of chronic inflammatory cell was evident in
allo group.

Radionuclide bone scanning was done from randomly
selected cases of both groups.  More increased tracer
uptake was seen in the operation site of hydroxyapatite
group than that of  in the allo group (Fig. 7, Fig. 8) which
is also supported by the finding of Jun14. More tracer
uptake of radioactive iodine indicates good osteoblastic
activity. On the other hand slight tracer uptake indicates
average or poor osteoblastic activity.

Post operative infection was not found in hydroxyapatite
bone graft group and 5(35.7%) in allogenic bone graft
group and the difference was statistically significant
(p<0.05). Infection occurred in 1(20.0%) in maxilla and
4(80.0%) in mandible (Table-II).

The infection was remarkably less in the hydroxyapatite
group because of its fine granular structure which
contributed to very reduced anatomical dead space than
that of the allografts which had larger particles which

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contributed to infection. After placement of hydroxyapatite
as a graft it solidifies and work as single unit of
osseointegrated structure that also contributes to less
infection than the allo group which is supported by the
findings of Zasacki 10. Infection occurred usually with in
the one week after operation and presented by the features
of localized swelling and exudation which leads to
exposure of grafted materials. This condition was then
treated by removal of the graft material and curettage of
necrosed tissue and use of proper antibiotics.

The allograft group was more infected than the
hydroxyapatite graft group may be due to loss of biological
properties secondary to its processing which was supported
by Friedlander 6. Other reasons for this inconsistency
include variable donor age with material from older donors
being less osteoinductive, how carefully the material is
processed, the level of residual calcium and the final
particle size of the prepared graft reported by Schwartz
and coworkers14.

Conclusion:
The radiological, histopathological and scintigraphical
outcome of the patients treated with hydroxyaptite granule
bone graft were clinically and statistically better in
comparison with those treated with allogenic bone graft.
None of the patient of the hydroxyapatite group was
infected. This safe and osteoconductive HA appears
suitable for filling bone defects and bone cavities, showing
less resorption and a rapid osseous integration.

References:
1. Stockdale CR, Chandler NP. The nature of the periapical lesion: a

review of 1108 cases. J  Dent  1988;16: 123-129

2. Marble H.B.  Jr, Captain DC USN. Homografts of freeze –dried
bone in cystic defects of the jaws. Federal dental services 1968;
26(1): 118.

3. Banwart JC, Asher MA, Hassanein RS. Iliac crest bone graft
harvest donor site morbidity: A statistical evaluation. Spine 1995;
20: 1055-60.

4. Cowley SP, Anderson LD. Hernias through donor sites for iliac-
bone grafts. J Bone Joint Surg Am 1983; 65: 1023-25.

5. Summers BN, Eisenstein SM. Donor site pain from the ilium: a
complication of lumbar spine fusion. J Bone Joint Surg Br 1989;
71: 677-80.

6. Freidlaender GE. Immune responses to osteochondral allografts
Current knowledge and future directions. Clin Orthop 1983; 174:
58-68.

7. Constanz BR, Ison IC, Fulmer MT. Skeletal rapair by in situ
formation of the mineral phase of bone Science 1995; 267: 1796-
99.

8. Rosen HM, McFarland MM. The biologic behaviour of
hydroxyapatite implanted into the maxillofacial skeleton. Plast
Reconstr Surg 1990; 85: 718–23

9. Zasacki W. The efficacy of application of lyophilized, radiation
sterilized bone graft in orthropaedic surgery. Clin Orthro Relt Res
1991; 272: 82-87.

10. Francis MD, Horn PA, Tofe AJ. Controversial mechanism of
technetium-99m deposition on bone. J Nucl Med 1981; 22: 72.

11. Harbert JC. The musculoeskeletal system In: Harbert JC, Eckelman
WC, Newmann RD (eds). Nuclear medicine: diagnosis and
therapy. New York: Thieme 1996; 801-63

12. Zuev VP, Dmitrieva LA, Pankratov AS. The comparative
characteristics of stimulators of reparative osteogenesis in the
treatment of periodontal diseases [Article in Russian]’,
Stomatologiia (Mosk) 1996; 75(5): 31-34.

13. Schwartz z. Ability of commercial demineralized freeze- dried
bone allograft to induce new bone formation. J Periodontol 1996;
67( 9): 925- 30.

14. Jun Manabe Pasteurized autologous bone graft in surgery for bone
and soft tissue sarcoma J Clin Orthop 2004; 419: 258.

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