Ministry of Education & Training Ministry of National Defense
108 Institute of Clinical Medical & Pharmaceutical Sciences
VO VAN NHAN
DENTAL IMPLANT PLACEMENT ON ALVEOLAR
BONE GRAFTED PATIENTS AFTER CLEFT LIP AND
PALATE RESCONTRUCTIVE SURGERY
Specialty: Odonto - Stomatology
Code: 62.72.06.01
PH.D THESIS SUMMARY
Hanoi - 2014
THE RESEARCH WAS FINISHED AT
108 INSTITUTE OF CLINICAL MEDICAL &
PHARMACEUTICAL SCIENCES
Full name of scientific instructors:
1. Assoc.Prof. Ph.D. Le Van Son
2. Ph.D. TaAnh Tuan
Judge 1:Assoc.Prof. Ph.D. Trinh DinhHai
Judge 2: Ph.D. Le Hung
Judge 3: Prof. Ph.D. Le GiaVinh
The thesis will be defended before the Thesis Assessment
Council at Institute level
At , date
month
year
Be able to search the thesis at:
1. National library
2. 108 Institute of Clinical Medical & Pharmaceutical
Sciences Library
1
I. RATIONALE OF THE SUBJECT
Cleft lip and palate (CLP) is the most frequently reported
congenital birth defect in the cranio-maxilo-facial field.
According to WHO, the overall incidence of cleft lip and palate is
reported around 1/500 live births [138]. This incidence is different
depending on regions and races:it’s low in the black and high in
Japanese, Chinese and Indian-American. In Vietnam, this
incidence is about 1/709 to 1/1000 [2], [7].
Around the world, some clinicians successfully applied
implant treatment for cleft lip and palate patients like Verdi
(1991) [139], Kearns (1997) [68],…. In Vietnam, the research on
cleft lip and palate patients mainly assess epidemiology and cleft
lip - palate closing technique [1], [3], [4], [5], [7], a few studies
were takenabout alveolar bone graft such as study of Nguyen
Manh Ha (2009) [6], or implant placement in normal patients
without defects of Ta Anh Tuan (2007) [8]. Thus, the implant
placement on the grafted bone and implant prosthetic on CLP
patient is the problem that has not been studied comprehensively
in Vietnam. Meanwhile, the demand for treatment is huge since
most CLP patients have not had bone grafts and dental
restorations as of yet.
With the desire to implement the implant technique for CLP
patients in Vietnam and perform a systematic scientific research,
we conducted the thesis "Dental implant placement on alveolar
bone grafted patients after cleft lip and palate reconstructive
surgery".
II. RESEARCH OBJECTIVES
1. Evaluate jaw bone condition after alveolar cleft bone graft
2. Evaluate the success of implant treatment.
2
III.
MEANING
The thesis provides a new treatment method for patients with
cleft lip and palate defect, not only torecoverthe function but also
to meet the aesthetic demand helping patients communicate
confidently for community integration.
IV. THESIS STRUCTURE
The thesis consists of 121 pages, not including appendices and
references. The contents of the thesis are: Introduction (2 pages),
Literature review (31 pages), Research subjects and method (29
pages), Research results (20 pages), Discussion (36 pages),
Conclusion (2 pages), Recommendations (1 page). The thesis has
23 tables, 4 diagrams, 12 charts, 69 pictures, 144 references (9
Vietnamese, English 135).
Chapter 1: LITERATURE REVIEW
1.1. CLEFT LIP AND PALATE
Cleft lip and palate are birth defects causing deficiency and
deformities of the nose, lips, palate that affects the formation of
unerupted tooth, teeth eruption, malocclusion, mastication,
distortion of the mesial floor and inferior floor of the facial,
pronunciation, the aesthetic and psychological diseases [94], [65].
Therefore, those who suffer from this malformation always feel
inferior andcan feel distance from community.
The treatment of CLP defects is a long process from the child
still in the womb to anadult with the cooperation of many experts
and various techniques including psychological counselling,
primary lip and palate repair surgery, alveolar cleft bone graft
surgery, orthodontic treatment, dental restorations, ... [101], [106].
3
1.2. ALVEOLAR CLEFT BONE GRAFT
1.2.1. The necessity of alveolar cleft bone graft
Alveolar cleft bone graftingprovides room for orthodontic
movement of the teeth in the position of #3 and #2 (canine and
lateral incisor) to erupt into the cleft or for dental prosthesis,
maintain bony support of teeth adjacent to the cleft, preserve the
health of the arch and facilitates closing of the fistula in the
secondary bone grafting [138].
1.2.2. Flap preparation forgrafted recipient
Flap designs in alveolar cleft bone graft surgery are extremely
important to determine the success of the surgical procedure as it
provides adequate soft tissue for the closure over the bone graft
without flap tension and dehiscence. There are many flap design
techniques such as thelateral sliding flap, the oblique sliding flap,
the buccal finger flap, the nasal lining flap and the palatal flap
[18].The flap designs can be used by single or multiple
techniques, depending on the clinical situation for optimaltensionfree closure.
1.2.3. The choice of donor site for graft material
Autogenous bone can be taken from many different sourcesin
which the tibia is first used, followed by iliac crest, ribs, chin and
calvarial bone (SindetPerdersent and Enermark 1988) [116].
Some authors have done a lot of research in order to replace the
autogenousbone material in alveolar bone grafting,such as with
demineralized freeze-dried bone combined with iliac cancellous
bone of Steven (2009) [121], β Tricalxium-phospate (TCP) of
Ruiter (2012) [107] or BMP-2 (bone protein) of Dickinson (2008)
[39] but studies using these materials is still not advancedand is
4
not commonly applied. Therefore,autogenousgrafted bone is still
considered as the golden standard for graft material of alveolar
cleft recovery.Ananth’s research (2005) summarized 110 centers
with 240 CLP surgical teams, which showed iliac crest bone is
still the most popularmaterial used by 83% [19].
1.2.4. Techniques of placing grafted bone
There are many techniques in placing the grafted bone in the
cleft such as iliac crest cancellous bone graft [46], iliac crest bone
block graft [31], autogenous bone graftwithartificial membrane
barriers covering graft material [100], the use of a cortex bone
plate (CBP) along the lining of thepalatal suture line[85] and
lateral corticalbone plates from the symphysis[127]. But so far,
these techniqueshave not been commonly used in alveolar cleft
bone grafting.
1.2.5. Evaluation methods of bone graft result
1.2.5.1. Means of evaluation
Some authors evaluate the results of bone graft by histology
[60] but the most popular is still by computed tomography,
including periapicalradiography, occlusalradiography, panoramic
radiography, conventional CT and Cone Beam CT.
The results of alveolar cleft bone graft was previously
mainlyassessed
by
periapicalradiography
and
occlusalradiography[46], [54], [55], [72], [81] but these films did
not measure the buccal-lingual distance of the graft [77].
Therefore, Cone Beam CT today has become popular and useful
in assessing changes in volume and size in 3-dimension[59],
[137].
1.2.5.2. Evaluation scale
5
Nowadays, for the assessment of the alveolar bone graft outcome,
most of thestudies usethe combination of two-dimensional film
(periapicalradiography
and
occlusalradiography) through the
evaluation scale of the bone
bridge formation in the cleftand
CTCone Beam to examine the 3dimensional size or volume of the
Figure 1.16:Enermark scale[42]
graft [24], [26], [61], [79], [128],
[137]. Several scales are applied such asEnermarkscale (1987)
[42], Berglandscale (1986) [24] using periapical radiographyand
Kindelanscale (1997) [71] using occusal radiographyto assess the
bone heightbetween the teeth in the cleft areas, successful results
was obtained when more than 50% bone fill in the cleft areas
(Figure 1.16).
Thesescales are popular because it is easy to apply in
comparison with Long scale [81] and Witherow scale [140].
1.3. DENTAL IMPLANT
Osseointegratedimplant that was developed by professor
Branemark in the 1960s has now becomeconventional treatment
method to restore the missing teeth as well as congenital teeth
deficiency in CLP patients. In 1991, Verdi [139] reported a first
case of successful alveolar bone grafting and implant treatment,
then followed by some reports of implant treatment in similar
situation as Fukuda (1998) [50], Kearns (1997) [68], Lilja (1998)
[79], Takahashi [130], [131], ... Implants have the supported
fixationcomponent whichauthors have developed many flexible
solutions for implant prosthesesfor various and complex situations
of CLP patients after alveolar cleft bone grafting. However, most
6
of the above studies have evaluated the success of implant
osseointegration, not the aesthetic of implant prostheses.
Chapter 2: RESEARCH OBJECTS AND METHOD
1.1. Research subject
- Patient selection criteria: Patients over 15 years old, in good
health for endotracheal anesthesia, already has had palatoplasty,
complete unilateral alveolar cleft, lack of permanent tooth germ in
the cleft andhas not had any alveolar cleft bone graft.
- Elimination criteria: No alveolar cleft, no unilateral or bilateral
alveolar cleft.Patientswho disagree to participate in the research.
1.2. Research method
1.2.1. Research design:
This thesis useda prospective uncontrolled clinical trial method
to evaluate alveolar cleft bone graft outcomes and implant
success.
Sample size: 32 patients by the averageestimating formula.
1.2.2. Research time:August, 2010 to February, 2014.
1.2.3. Research procedure:
Firstly, patient information was collectedwith a case history
form. After orthodontic and general dental treatment, alveolar
cleft bone grafting surgery was conducted with the technique of 2
iliac corticocancellousbone block autograft. 4 to 6 months later,
the implant placement was performed; 6 months later, prostheses
on the implant was executed.There was continued follow-up 15
and 18 months after the alveolar cleft bone grafting.
1.3. Surgical procedure
1.3.1. Iliac bone block harvesting surgery
A5cm incision over the superior iliac crestwas made 1 cm from
anterior superior iliac spine to prevent damage of the lateral
femoral cutaneous nerves. Thesubcuticular structure and
7
mucoperiosteumwas infiltrated and then dissection of the
periosteumwas carried out to expose iliac bone. Ultrasonic
piezotome device was used to make 4 cuts: the first cut of 4cm on
the superior iliac crest away from the cortical bone in the
abdominal cavity of 0.5cm, the second and the third cuts with the
length of 2cm were perpendicular to the first cut. The fourth cut
was perpendicular to the second and the third cuts. These four
cuts created a rectangle. A chisel was used to harvest the bone
block including the cortical and cancellous bone with the size of 4
x 2 x 0.5cm3. Afterthat, hemostatic sponge was placed and 2 layer
sutures were used:periosteum suture and subcuticular suture. The
bone blocks were kept in a small stainless steel cup in saline for
moisture preservation.
1.3.2.
Alveolar cleft bone graft surgery:
Flap design: The incision began at the edge of the cleft and
wentover the cleft’s perimeter,divided the cleft into 2 parts, then
went down to the alveolar crest, moved to the two sides ofthe
teeth’s neck next to the cleft and thencontinued to follow the
gingival contours to the distalof tooth #4 or #5 and upwardto the
vestibularforming avertical incision. At the top of the vertical line,
an incision was made with the vertical line ofangle 120° to easily
slidethe flap to the lateral and downwardposition (Figure 2.28).
After that, from the incision on the alveolar crest that stayed
closely to the neck (lateral) of the two teeth adjacent to the cleft,
the incision was continued along the gingival sulcus on the labial
side to the teeth at the two sides of the cleft.
The nasal flap closure began with the suture from the buccal
to the labial at one side of the flap edge, then the dissection was
8
continued from the labial to the buccal at the contralateral flap
edge. Finally, the knot was made (Figure 2.29).
Based on the bone grafting technique of two lateral cortical
bone plates from the symphysisby Tadashi Mikoya(2010) [127],
we
introduced
two
iliac
corticocancellousblock
grafting
techniques in this study with the technical steps as follows:
Step 1: Placement of cortical bone plate on the labial (nasal)
aspects of the alveolar process defect: The iliac bone block was
cut into 2 blocks. The first corticocancellous block with the size
of the cleft size was placed on the sutured nasal mucoperiosteum
(Figure 2.30). The cancellous bone was added on the plate until it
nearly filled the cleft (Figure 2.31)
Figure 2.30: The bone block on the nasal lining
Figure 2.28: The incision for flap design on the vestibular
Figure 2.29:
Nasal flap closure
Figure
2.32:
Theby
bone
block onbone
the vestibular was secured
by2.33:
screws
Figure 2.31: The cleftwas
nearly
filled
cancellous
Figure
Wound closure
Step 2: The second corticocancellous block with a larger size
than the cleft was placed on the grafted cancellous bone covering
the whole cleft and secured by screws for a tight fixation(Figure
2.32).
9
Step
3:
The
wound
closure:
the
palatal
mucoperiosteumandthe vestibular mucoperiosteum wereclosedby
the suture on the alveolar crest. Vestibular mucoperiosteum
wassutured onboth sides of the cleftfrom the ridge of the alveolar
crest towards thevestibular recess. The suture was continuedto
recover the sulcus gingiva of the tooth from the cleft area. Finally,
mucosa closure was made with the vertical tension-freeincision
from the vestibular recess towards thealveolar crest (Figure 2.33).
1.3.3.
Implant
placement
surgery
and
implant
prosthodontics
+ Implant placement in the aesthetic zone [29]: Using
implant surgical guide to ensure: Implant direction passes the
occlusal edge of the further prostheses;In the buccal-lingual
dimension, the buccal side of the implant is 2mm from the buccal
side of the cortex;In the apical-coronal dimension, the implant
shoulderis a distance of 3mm from the free gingival margin;In the
mesial-distal dimension, the implant has a distance of at least
1.5mm from the next root.
+ Prosthodontics: 6 months after the implant placement,
secondary surgery of gum opening was carried outfor inserting the
healing screws, then 3 weeks later, the impression is done for the
prosthodontics.
1.4. Assessment criteria
1.4.1. Soft tissue condition at the recipient site
- Good: pink mucosa, dry, tight and healing scar
- Average: dehiscence but nograftexposure.
- Bad: infection,dehiscenceorbone graftexposure.
1.4.2. Oronasal fistula
10
- Closed: Clinical examination showed the fistula was closed.
- Unclosed: Clinical examination showed the fistula still exists.
1.4.3. Assessment of alveolar bone graft
-
Assessment
of
bone
bridge
formation
by
periapicalradiography
Enermark scale was used for assessing bone formation in the
cleft[42] according to 4 levels:
• Type I: 75% - 100% bone recovery compared to the initial
bone graft site.
• Type II: 75% - 50% bone recovery compared to the initial
bone graft site.
• Type III: 25% - 50% bone recovery compared to the
initial bone graft site.
• Type IV: 0% -25% bone recovery compared to the initial
bone graft site
Type I and Type II are considered successful. Type III is
partial failure. Type IV is completely failure.
-
Assessment of bone grafting result by CT Cone Beam
• The apical-coronal distance: marked as d, is measured
from the lowest point and the highest point of the grafted bone on
CT slices through the adiaphanouslocation axis on the surgical
guide.
• The buccal-lingual distance: marked as r, is the average of
the apical-coronal distance of 1/3 superior (a), of 1/3 mesial (b)
and of 1/3 inferior (c), r = (a+b+c)/3.
11
• FollowingRenouard’s standard (1999): if the apical-coronal
distance is at least 7mm and the buccal-lingual distance is at least
4mm then there isenable for implant placement [47]
1.4.4. Assessment of implant placement
Assessment of the success of implant oseointegration by
Misch’s criteria (2008) [89] included 4 levels:
o Success: if no pain in function, no clinical mobility is
noted, less than 2.0 mm of radiographicallycrestal bone loss is
observed compared with the implant insertion surgery, no history
of exudate.
o Satisfactory survival: if they are stable, no observable
pain and mobility in function, radiographic crestal bone loss is
between 2.0 and 4.0 mm from the implant insertion.
o Compromised survival: with no pain in function, no
mobility, greater than 4mm radiographic crestal bone loss but less
than 50% from around the implant, more than 7mm of probing
depths, often accompanied with bleeding.
o Failure: if any of these conditions are presented: pain in
function, mobility, more than ½ implant length of bone loss,
uncontrolled exudate, or has been surgically removed.
-
Assessment of the implant prosthesis’saesthetic:
+ Following pink esthetic score (PES) and white esthetic score
(WES) based on Belser’s standard (2009) [23]: The pink esthetic
score assesses the soft tissue condition around the implant through
5 factors compared to the contralateral tooth: mesial papilla, distal
papilla, curvature of the facial mucosa, level of the facial mucosa,
and root convexity, soft tissue color. White esthetic score presents
the esthetic of the implant restoration with 5 parameters in
comparison with the contralateral reference tooth: general tooth
12
form, volume of the clinical crown; color, surface texture and
other characterization. A maximum total score WES and PES of
more than 12 was set for being esthetically successful, a score of
12 for clinical acceptance and a score of under 12 for
estheticalfailure.
+ Assessment of the degree ofpatient satisfaction by the
score of 1 to 9 with a score of 1, 2, 3 for unsatisfactory, a score of
4, 5, 6 for satisfactory and a score of 7, 8, 9 for above satisfactory
[43].
Chapter 3: RESEARCH RESULTS
3.1.
Clinical characteristics of the study sample
- Total of 32 patients with the average age of 20.2 (15-29), 23
females and 9 males in which 23 had left-side UCPL and 9 had
right-side UCLP. 100% of patients presented with an oronasal
fistulaand
misalignment.
Therefore,
all
patients
required
orthodontic treatment with the average time of 12.5 months for
treatment.
- The occlusion of Angle Class I was found in 53.1% patients,
Angle Class III in 28.1% patients, the occlusion of cross bite,
edge to edge or open bite in the anterior but Angle class I in the
posterior was reported in 18.7%. Each patient had 9.8 decay on
average.
3.2.
Result of alveolar bone graft
3.2.1.Mucosa condition of the recipient
At the follow-up 7 days postoperatively, 29 cases (90.6%)
reported good healing. A wound dehiscence occurred in three
patients (9.4%) resulting in a partial loss of bone, but the region
13
healed uneventfully after exfoliation of small bone fragments.
After 4 to 6 months, 100% of cases showed good healing.
3.2.2.Result of alveolar bone graft
3.2.2.1.Result of bone formation usingEnermark scale
In the follow-up 4 to 6 months after the bone graft surgery,
the bone formation type I was 90.6% and type III was 9.4%.
There was no change after 12 and 15 months.
After 18 months postoperatively, 1 patient appeared bone
resorptionwhich dropped from type I to type II. However, type
Iand type II are considered as successful by Enermark, so the total
success rate of the graft was 90.6% (Table 3.30). Bone bridge
formation in the cleft at the point of 18 months compared with the
point of 6, 12 and 15 months showed no statistically significant
differences (p<0,05). Thus, implant placement can limit bone
resorption.
Table 3.30: Result of bone formation at 6, 12, 15 and 18
monthsafter alveolar bone graft (n=32)
Bone bridge level
Point of
Total
times
I
II
III
IV
4-6
29
0
3
0
32
months
(90.6%)
12 months
29
0
32
0
32
3
32
(9.4%)
0
(90.6%)
15 months
29
(9.4%)
0
(90.6%)
18 months
p= 0.764
3
3
(9.4%)
28
1
(87.5%)
(3.1%)
0
(9.4%)
14
3.2.2.2. Result of bone formation using CT Cone Beam
On axial CT at 6 months postoperatively, the mean apicalcoronal distance of 11.4.0±2.4 mm and the mean buccal-lingual
distance of 6.1±1.0mm was reported. According to Renouard’s
standard [47], 29 of 32 alveolar clefts (90.6%) displayed thebone
bridge formation enable for implant placement. 3 clefts
(9.4%)showed insufficient bone for implant placement which
indicated fixed bridge restorations.
3.3. Result of implant placement
9,4%%
- Total of 32 implants were placed, of which 31 implants were
0%%
of size 3.8 x 10mm and 1 implant was 3.8 x 12mm. Of 32
patients, 3 patients had 2 implants placed, 26 patients had 1
implant placed.
- Initial
implant
stability:
over
35N/cm2in
2
12.4%
of
2
implants,20-35 N/cm in 43.8%and 15-20N/cm in43.8%.
- Additional bone graft during implant placement were
performed in all 32 patients, in which 90.6% usedcancellous
particulate bone graft and 9.4% used ring bone and cancellous
particulate bone graft.
3.3.1.
Result of implant osseointegration
Table 3.31: Result of implant osseointegration at 12, 15 and 18
months after alveolar bone (n=32)
Point of times
Post
Post
bone
implan
graft
t
surger
surger
y
y
Results on implant osseointegration
Total
Succes
s
Satisfact-
Compro-
ory
mised
survival
survival
number
Failure
of
implant
15
12
6
32
0
months
month
(100%)
0
0
32
(100%)
s
15
9
32
0
months
month
(100%)
0
0
32
(100%)
s
18
12
31
1 (3.1%)
months
month
(96.9%
s
)
0
0
32
(100%)
p=0.999
After 12 months follow-up,100% implants were successful and
therewas no change after 15 months follow-up. However, after 18
months, 96.9% (31 implants) were successful, 3.1%(1 implant)
appearingwith 2mm bone loss making it become satisfactory
survival, no implant failure. The total survival of implants in good
function were still 100%. The survival rate at the point of 12 and
15 months had no significant difference compared to the point of
18 months (p<0.05).
3.3.2.
+
Esthetic result of the prostheses on implant
Esthetic result followed pink esthetic score (PES) and
white esthetic score (WES) based on Belser’s standard (2009)
[23]:
Table 3.32: Esthetic resultof prostheses on implant at9 and 12
monthsafter implant placement(n=32)
Point of times
Esthetic result of prostheses
on implant
Post
Post
Esthetical
Clinical
Esthetical
bone
implan
success
acceptance
failure
Total
16
graft
surgery
t
surger
y
15
9
18
5
9
32
months
months
(56.3%)
(15.6%)
(28.1%)
(100%)
18
12
18
5
9
32
months
months
(56.3%)
(15.6%)
(28.1%)
(100%)
In the follow up of 9 and 12 months after implant placement,
18 implant prostheses (56.3%) were esthetical success, 5
prostheses (15.6%) were clinical acceptableand 9prostheses
(28.1%) were estheticalfailure (Table 3.32).
-
Result of degree of patient satisfaction of the prostheses on
implant:
In the follow up of 9 and 12 months after implant placement,
21 patients (72.4%) were above satisfied with their prostheses, 8
patients (27.6%) satisfied and no patients disappointedwith their
prostheses on implants (Table 3.33)
Table 3.33: Result of the degree of patient satisfactionof the
prostheses on implantafter9 and 12 months after implant
placement (n=29).
Point of time
Post
bone
graft
surgery
Post
implant
surgery
Patient satisfaction of the
prostheses on implant
Above
satisfied
Satisfied
15
9
21
8
months
months
(72.4%)
(27.6%)
Total
Unsatis
-fied
0
29
(100%)
17
18
12
21
8
months
months
(72.4%)
(27.6%)
29
0
(100%)
Chapter 4: DISCUSSION
4.1. The characteristics of the study sample
In our study, all 32 patients presentedwith teeth around the
cleft misalignment. The occlusion Class III Angle was 28.1%
while Class III Angle in normal patients without defects in Dong
KhacTham’sstudy was 21.7% [9]. Thus, patients with Angle Class
III in our study wassignificantlyhigher than patients without
defects (p <0.05). This rate was suitable with Posnick’sstudy
(2000) [105].
All patients were treated orthodontic for aligning and making
suitable horizontal spaces forfuture prostheses, facilitating
flapdesign, flapdissection and flap closure. It also helpsplacing,
fixing the graft, determining the volume of bone graft easily as
well as the prognosis of the location and orientation of the implant
that fit the future prostheses. Furthermore, orthodontic treatment
was continued after bone graft surgery that is recommended bya
lot of authors as the traction on bone graft will help stimulate the
graft’s development (Turvey 1984 [136]).
Each patient had 9.8 decays on average and the DMFT Index
(Decayed, Missing and Filled Teeth)was 10.5 with no
significantly difference (p=0.388> 0.05), whichmeans the subject
had
not
had
oral
treatment
before.
12
patients
(37.5%)presentedwith residual tooth in the cleft area. Jia (2006)
[64] said that poor oral hygiene often leads to infection,
complications and dehiscence after bone graft surgery. To prevent
the above complications, all patients received dental treatments,
18
gum treatment and oral hygiene instructions in the treatment
process. Residual teeth in 12 cases were extracted at least 2
months before the bone graft surgery to ensure there wasmature
gum tissue in the extraction area making better condition for flap
closure.
4.2. Timing and purpose of the alveolar bone graft
In our study, all patients receivedintermediate secondary bone
grafting in the age of over 16 years with the purpose of implant
restoration. However, according toDempf’sresearch [36], the
alveolar ridge height after intermediate secondary bone
graftingwas reported be lower than after late secondary bone
grafting (tertiary). This was a challenge we had to face in this
study becauseinsufficient bone height would affect the implant
stability and the restorations’ aesthetic [36]. Therefore, to
overcome this difficulty, we performed additional bone grafts for
all cases in implant placement.
4.3. The technique of the alveolar bone graft
Based on the technique of a cortex bone plate (CBP) along
the lining of the palatal suture line [85], especially lateral cortical
bone plates from the symphysis [127], we have modifieda two
iliac corticocancellous block graftin alveolar bone grafting. With
this new technique, screws were used to fix the bone graft in the
vestibular side. Compared with Tadashi’s technique, the
symphisis cortical plates are just inserted on the cleft, while
according to Buser (2009), the fixation of the graft is definitely an
important factor for the successof bone grafting techniques [28].
In the technique of two iliac corticocancellous blocks, we
combined the rigid mechanical properties of cortical bone that
limit bone resorption and easily obtain the implant initial stability
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