Randomized Clinical Trial of Maxillary Sinus Grafting …...Randomized Clinical Trial of Maxillary...
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Randomized Clinical Trial of Maxillary Sinus
Grafting using Deproteinized Porcine and
Bovine Bone Mineral
Hyun-Ki Shin
Department of Dentistry
The Graduate School, Yonsei University
[UCI]I804:11046-000000514528[UCI]I804:11046-000000514528
Randomized Clinical Trial of Maxillary Sinus
Grafting using Deproteinized Porcine and
Bovine Bone Mineral
Directed by Professor Kyoo-Sung Cho
The Doctoral Dissertation
submitted to the Department of Dentistry
and the Graduate School of Yonsei University
in partial fulfillment of the requirements for the degree of
Ph.D. in Dental Science
Hyun-Ki Shin
December 2017
This certifies that the Doctoral Dissertation
of Hyun-Ki Shin is approved.
Thesis Supervisor : Kyoo-Sung Cho
Chang-Sung Kim
Jung-Seok Lee
Jung-Kiu Chai
Chong-Kwan Kim
The Graduate School
Yonsei University
December 2017
감사의 글
2012년 9월, 두근거리는 마음으로 시작했던 치주과 대학원 과정이 어느덧
학위논문과 함께 막바지에 다다랐습니다. 그동안 도움을 주신 모든 분들께
짧게나마 감사의 글로 마음을 전하고자 합니다.
먼저, 치주과 수련 기간과 대학원 과정에서 부족한 제게 아버지와 같은
마음으로 인간적, 학문적인 가르침을 주시고 치과의사로써 지표가 되어 주신
조규성 지도교수님께 깊은 감사의 말씀 드립니다. 또한 치주과의 버팀목으로
계시며 열정으로 제자들에게 가르침을 주시는 김종관 교수님, 항상 따뜻한
관심과 격려로 힘이 되어 주신 채중규 교수님, 임상뿐만 아니라 연구에서도
냉철한 안목을 갖게 해 주신 김창성 교수님, 항상 가장 가까운 곳에서
따뜻함으로 감싸주시며 이 논문이 완성되기까지 많은 도움을 주신 이중석
교수님께 진심으로 감사의 말씀을 드립니다. 또한 수련 기간 동안 새로운
시각의 중요성을 일깨워 주신 최성호 교수님, 비판적이고 창의적인 안목을
가질 수 있게 해 주신 정의원 교수님께 감사드립니다. 아울러 대학원 기간
동안 힘이 되어 준 선후배 의국원, 특히 수련 동기들에게 깊은 감사의 마음을
전합니다.
마지막으로, 저를 낳아 주시고 길러 주신 부모님, 현실적인 조언과 충고로
힘이 되어 주시는 장인어른과 장모님, 항상 곁에서 함께 하는 소중한 가족들,
가장 가까이서 저를 지지해주는 사랑하는 아내에게 무한한 감사의 말씀을
드립니다.
2017년 12월
신 현 기
i
Table of Contents
List of Figures ············································································ ii
List of Tables ············································································ iii
Abstract (English) ······································································ iv
I. Introduction ············································································ 1
II. Materials & Methods ································································ 4
1. Study Design and Population ·················································· 4
2. Sample Size Determination ···················································· 5
3. Randomization and Allocation ················································· 5
4. Blindness ········································································· 6
5. Surgical Protocols and Timetable ············································· 6
6. Outcome Variables ······························································ 7
7. Statistical Analysis ······························································ 9
III. Results ·············································································· 10
1. Participant Population and Clinical Findings ······························ 10
2. Radiographic Results ························································· 11
3. Histological Results ··························································· 12
IV. Discussion ·········································································· 14
References ·············································································· 18
Figure Legends ········································································· 22
Tables ···················································································· 24
Figures ·················································································· 26
Abstract (Korean) ······································································ 32
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List of Figures
Figure 1. Representative clinical photographs showing the procedures of laterally
approached sinus grafting.
Figure 2. Radiographic analysis by overlapping computed tomography (CT) images
from the time-points immediately and 6 months after surgery.
Figure 3. Flow chart of this clinical trial.
Figure 4. Representative radiographic results from the control and test groups (A).
Scatter plot of the morphometric results of the linear and volumetric
measurements (B).
Figure 5. Representative overall views of histological samples from the grafted sinuses.
Figure 6. Representative histological photographs at high magnifications and
histomorphometric results.
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List of Tables
Table 1. Demographics of patient population and maxillary sinus (mean ± SD).
Table 2. Measurements of radiographic and histometric analyzes (mean ± SD).
iv
Abstract
Randomized Clinical Trial of Maxillary Sinus Grafting using
Deproteinized Porcine and Bovine Bone Mineral
Hyun-Ki Shin, D.D.S.
Department of Dentistry
The Graduate School, Yonsei University
(Directed by Professor Kyoo-Sung Cho, D.D.S., M.S.D., PhD.)
Background: Deproteinized porcine bone mineral (DPBM) was recently developed and
commercially available in maxillary sinus grafting, in which deproteinized bovine bone
mineral (DBBM) was widely used.
Objective: The present randomized controlled clinical trial aimed to compare histological
bone quality and radiographic volume stability in maxillary sinuses grafted with DPBM
and DBBM.
Materials and methods: Twenty sinuses in 16 participants were enrolled and randomly
allocated to control and test groups using sequentially numbered, sealed envelopes;
laterally approached sinus grafting with DBBM and DPBM, respectively. All participants
were blinded to the group assignment during the entire experiment. After standardized
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osteotomy at the lateral wall of the maxillary sinus, the sinus membrane was elevated,
and the control or test biomaterial was grafted. Computed tomography (CT) images were
taken immediately after surgery, and another CT and trephine biopsy was taken for
radiographic and histological analyses after 6 months. The histological bone quality was
measured as a primary outcome, and changes in the height and volume of the graft were
evaluated in the reconstructed CT images as secondary outcomes.
Results: Fifteen sites (7 and 8 sites for control and test group) in 11 participants were
finally included in the per-protocol (PP) analysis, and 16 sites (7 and 9 sites, respectively)
in 12 participants were included in the intention-to-treat (ITT) analysis; there were four
drop-outs and one minor protocol violation. In both statistical analyses, the test groups
showed comparable new bone formation and residual biomaterials in histology, and both
groups exhibited minimal volume/height changes in radiographies. However, smaller
sizes of residual biomaterials were observed in the histological samples from the test
compared to control sites, despite the use of the same sizes of both biomaterials.
Conclusions: The results suggested that DPBM might produce comparable bone
formation and volumetric stability with DBBM in maxillary sinus grafting, however,
further clinical study with longer-term periods and larger sample sizes should be needed
for confirming this suggestion.
Keywords: sinus floor augmentation, deproteinized porcine bone, deproteininzed bovine
bone, randomized controlled trial
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Randomized Clinical Trial of Maxillary Sinus Grafting using
Deproteinized Porcine and Bovine Bone Mineral
Hyun-Ki Shin, D.D.S.
Department of Dentistry
The Graduate School, Yonsei University
(Directed by Professor Kyoo-Sung Cho, D.D.S., M.S.D., PhD.)
I. Introduction
Evidence-based dentistry is a systemic approach of analyzing studies related to
clinical issues on the basis of decision-making. In the choice of clinical protocol or
materials in the clinic, the decision for the most appropriate methodology could be based
on the scientific evidence, which could be affected by the level of evidence, from case
reports to randomized clinical trials/meta-analyses. In particular, dental clinicians manage
patients or diseases with many different dental materials; therefore, a comparative clinical
study is needed to facilitate the selection of dental material.
Several meta-analyses exist regarding regenerative bone tissue engineering such as
sinus graft and guided bone regeneration (GBR) (Al-Nawas and Schiegnitz, 2014;
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Handschel, et al., 2009); however, the conclusions were produced with a low evidence-
level, or conclusions could not be drawn because of highly limited numbers of clinical
studies, especially randomized clinical trials. In a recent systematic review article of
meta-analysis in sinus grafting (Esposito, et al., 2014), only one study could be included
as a comparative clinical trial for evaluating different bone substitutes (Lindgren, et al.,
2012), although many bone substitutes are used clinically based on preclinical studies.
In clinical dental procedures for bone tissue engineering, xenograft biomaterials have
been most widely used, and deproteinized bovine bone mineral (DBBM) has the most
powerful scientific evidence for sinus grafting, GBR and ridge preservation, including
preclinical and clinical studies (Araujo, et al., 2015; Benic, et al., 2016; Lee, et al., 2012).
This use of DBBM is a field-specific phenomenon, considering the orthopedic fields in
which allogeneic bone mineral is typically used. This phenomenon might be caused by
the specific aim of these procedures to add volume stability and qualitative bone
regeneration of the grafted sites. In a long-term (over 10 years) clinical result, DBBM
showed maintenance of its volume and well-remodeled lamellar bone around residual
DBBM particles (Mordenfeld, et al., 2010). Recently, DBBM has been used for
maintaining dimensions of alveolar ridge after tooth extraction based on the characteristic
of minimal resorbability (Araujo and Lindhe, 2009). In several clinical studies of sinus
grafting, DBBM was used as a positive control biomaterial.
Other xenograft materials from the other origins (swine and equine) have been
introduced in the clinical and research fields of dentistry under the banner of prevention
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of the bovine-specific disease transmission (Di Stefano, et al., 2009; Kim, et al., 2004;
Nannmark and Sennerby, 2008; Park, et al., 2012; Tete, et al., 2014). Although no
clinicians have reported disease transmission related to this method since DBBM was
first used several decades ago, a recent systematic review indicated a possible risk of
disease transmission related to prions (Kim, et al., 2013). Deproteinized porcine bone
mineral (DPBM) is one substitute for DBBM, and several researchers already introduced
DPBM for clinical dental procedures (Barone, et al., 2012; Barone, et al., 2016; Orsini, et
al., 2006; Scarano, et al., 2011) based on the structural/physiological similarities of bone
tissue between human and swine (Kim, et al., 2004). In our preclinical study using an
animal model, DPBM showed comparable bone regeneration and volume stability (Lee,
et al., 2013). However, controlled clinical studies are needed for clinical use in dental
fields. Therefore, the present study aimed to compare histological bone quality and
radiographic volume stability between the grafted maxillary sinuses with DPBM and
DBBM in a randomized controlled clinical trial.
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II. Materials and Methods
1. Study Design and Population
The present study was a single-blinded, randomized, controlled clinical trial for sinus
augmentation using DBBM (control; Bio-Oss, 0.25-1.0mm, Geistlich pharma AG,
Wolhusen, Switzerland) and DPBM (test; THE Graft, 0.25-1.0mm, Purgo Biologics,
Seoul, Korea). The study was performed at two single centers, the dental hospital of
Yonsei University and Inha University Hospital. The study was organized by Purgo Pro-
Biomimetics R&D Center, and all research procedures/records were monitored regularly
by Korea Medical Device Information and Technology Assistance Center. The protocol
for this study was designed in accordance with the Helsinki Declaration (revised version
of Tokyo at 2004) and Good Clinical Practice Guidelines and was approved by the
Institutional Review Board for Clinical research at Dental Hospital of Yonsei University
(Approval no. 2-2013-0038).
This trial included patients requiring sinus augmentation for dental implant
installation at the maxillary edentulous area, in which the residual bone height was within
the range of 1-6mm. The patients were required to be 20 years old to understand the
protocols/the informed consent and provide voluntary consent to participate for this study.
The following patients were excluded: smokers over 10 cigarettes a day, uncontrolled
diabetes/hypertension/coagulopathy, current maxillary sinus pathology, osteomyelitis,
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untreated periodontitis or mucosal disease in the oral region, and history of alcoholism,
medication of steroids/immune-suppressors within 2 weeks, allergic reactions to porcine
bone or bovine bone, radiotherapy, bisphosphonate medication. Sites that previously
received bone grafts/implant surgery or sites that previously underwent surgical removal
of pathologies were also excluded.
2. Sample Size Determination
The sample size was calculated using G*Power 3.1 software (Faul, Erdfelder,
Buchner & Lang) for comparison of two experimental groups with a given alpha level
and power, whichwere set at one-sided 10% and 80%, respectively. The effect size was
calculated based on previous data in proportion of newly formed bone in histological
samples from another previous clinical study of sinus grafting (Simunek, et al., 2008).
Eight sites per group were required using an effect size of 1.17, and 10 sites per group
were determined considering a drop-out rate of 20%. The number of sites per institute
was scheduled based on the number of participating surgeons: 16 at Institute A and 4 at
Institute B.
3. Randomization and Allocation
Participants were screened by the inclusion/exclusion criteria, and an informed
consent was obtained for each participant after detailed explanations. Each participant
was given an enrollment number and randomly assigned to the control/test group by a
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sequentially numbered, sealed envelope protocol. Briefly, the participants were given the
enrollment-number-matched, sealed envelope containing group assignment by means of
block randomization, which was created on a web-based program (sealedenvelope.com).
4. Blindness
At the operation visit, an assistant opened the allocated envelope immediately for
identifying the assignment before applying the graft materials, and the corresponding
materials were used. During the processes of enrollment and surgery (before opening the
envelope), surgeons/researchers were blinded to group allocation but were unblinded
thereafter. All of the participants were blinded to their assignment during the entire
experimental period. A researcher (J.S.L.) concealed the basic information from the
radiographic/histological data, and the other researcher (H.K.S.) measured/analyzed the
data blindly.
5. Surgical Protocols and Timetable
For standardizing clinical procedures, all researchers from both institutes attended a
calibration meeting, in which a principal investigator (K.S.C.) described the clinical steps
of sinus grafting using clinical photos and a video clip. In addition, a specially designed
osteotomy kit (LAS-KIT, Osstem, Seoul, Korea) was used for standardized size of
window opening. Antibiotics (amoxicillin 500mg or roxithromycin 150mg) and
analgesics (ibuprofen 200mg) were prescribed for medication at 1 hour before and 7 days
7
after surgery. All procedures were performed under local anesthesia using 2% lidocaine
with 1:100,000 epinephrine (Huons, Seoul, Korea). A crestal incision and a mesial
vertical incision were made for mucoperiosteal flap elevation, and then standard
osteotomy with a round shape of 7 mm in diameter was achieved at the lateral wall of the
maxillary sinus. The sinus membrane was elevated, and each corresponding grafting
material according to the assigned group was packed into the space underneath the
elevated membrane. During the entire procedures, repeated Valsalva maneuvers were
performed to evaluate if the sinus membrane was perforated, and the procedure
subsequently proceeded to the next step. After grafting the material (1-1.5g in both the
control and test sites), the osteotomy window was covered by a resorbable collagen
membrane (EZ Cure, Biomatlante, Vigneux, France). The primary closure was achieved
using 4-0 glyconate monofilament (Monosym, B-Braun, Aesculap, Center Valley, PA,
USA), which was then removed after 10-14 days (Figure 1).
Computed tomographies (CT) were taken immediately and 6 months after sinus
grafting for radiographic analysis. Immediately after obtaining the 6-months CT, a bone
tissue biopsy was taken using a trephine bur (2.3/3.0mm for inner/outer diameter) at the
sites that dental implants would be installed.
6. Outcome Variables
As a primary outcome value, qualitative analyses of the regenerated bone tissue were
performed on histology from biopsy samples. The samples were fixed in formalin and
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then decalcified in 5% formic acid over 10 days. After paraffin embedding, serial sections
were cut along the center of trephine samples. The two most central sections were stained
using hematoxylin-eosin and Masson’s trichrome. The histology was observed/taken with
a light microscope and camera system (BX50, Olympus, Tokyo, Japan) and
histomorphometrically measured using another computer software program (Image-Pro
Plus, Media Cybernetics, Silver Spring, MD, USA). The following parameters were
measured: total area of biopsy sample and area of newly formed bone/residual
materials/fibrovascular tissue. The proportion of each component within the total sample
area was calculated.
Radiographical dimensional alterations of height and volume in the augmented
sinuses were evaluated as a secondary outcome value in this study. Acquired CT images
were processed in DICOM format and three-dimensionally (3-D) reconstructed using
computer software (OnDemand 3D, CyberMed, Seoul, Korea). Two reconstructed 3D
images from the aforementioned two time-points were automatically overlapped in this
program based on the neighboring anatomic structures. On each sectional view from the
CT images, the grafted area was marked using color-coding by differential radiopacity,
and the height from the highest to lowest point in the graft was measured. Among these,
the highest value was used as the representative height of the augmented site. After
reconstruction processing, volumetric dimensions were calculated automatically in the
program (Figure 2). The height of preexisting bone was measured at the site that implant
was planned to be installed, and the mean value was used as a subject value.
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7. Statistical Analysis
The means and standard deviations of all parameters were calculated for the control
and test groups in the radiographic/histological analyses. Shapiro-Wilk test was
performed for evaluating normality of data, and the paired and unpaired t-tests were used
to determine the significance of any differences between two time-points and between
two groups, respectively. Statistical significance was set at p<.05.
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III. Results
1. Participant Population and Clinical Findings
Twenty-four volunteers participated in the clinical trial from October 2013 to
September 2014, and 31 sites were included. Eight patients were excluded before group
allocation; eight of these participants withdrew their agreement. Therefore, 20 sites from
16 patients were randomly assigned to two groups (n=10 for each group) and received
sinus grafting according to their allocations. Of these 20 sites, four sites in four patients
were also excluded before the implant/biopsy surgery period because of withdrawal of
surgery (n=2) and medication with prohibited drug (steroid; n=2). Sixteen sites (7 and 9
sites for control and test group) in 12 patients were ultimately subjected to the complete
procedures in this trial; however, one more site from the test group was excluded in the
data analysis after completion of experimental protocols because a violation of the
protocol (medication with prohibited drug; steroid) during the follow-up period was later
found in the medical records. Finally, 16 sites were included in the intention-to-treat (ITT)
analysis, and 15 sites were included in the per-protocol (PP) analysis (Figure 3).
Demographic results of the included patients are presented in Table 1; there were 7
male participants (aged 49.17±1.33 years, mean±standard deviation) in the control group
and 5 male/3 female participants (aged 40.83±9.97 years) in the test group. The
preexisting bone height of the surgical site was comparable between the control
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(2.06±0.43mm) and test groups (1.90±0.80mm); there were no statistically significant
differences between the groups. The demographics of the ITT set are also presented in
Table 1, including one exceptional site with both radiographic and histological data.
No complicated situations occurred during sinus grafting in any sites, except one site
in the test group showing Schneiderian membrane perforation (10mm diameter), which
was closed by suturing and covered with a collagen membrane before grafting
biomaterials. After surgery, all sites healed without major complications such as
postoperative infection; however, one site from the control group showed extensive but
transient facial swelling due to the patient’s carelessness (the use of warm pack instead of
a cold pack on the second day after surgery). At 6 months after surgery, clinical bone
density was evaluated as type 2 or 3 on implant site preparation, and primary implant
stability was achieved in all augmented sinuses with a favorable final torque (30-50Nm).
2. Radiographic Results
In the majority of control and test sites, well defined, augmented volume was stably
maintained with a similar shape and increased radiopacity. However, several cases
showed significant reduction of the augmented height at 6 months compared with
immediately after surgery; this reduction occurred in two sites in the control group and
two sites in the test group. Although radiopacity of the augmented volume increased with
time in the control and test sites, the control sites receiving bovine bone mineral showed a
higher density of radiopacity compared with the test sites (Figure 4A). There was no
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evidence of pathological changes (thickening or perforation) of the sinus membrane over
the augmented area immediately or 6 months after surgery.
In linear and volumetric measurements of the augmented area on CT images, limited
dimensional changes were found in the control and test sites. The heights (volumes) of
the control group were 15.06±2.61mm (1.74±0.47mm3) and 15.02±3.17mm
(1.90±0.52mm3) immediately and 6 months after surgery, respectively; the corresponding
values of the test group (PP set) were 12.97±1.31mm (1.56±0.45mm3) and
13.26±1.89mm (1.70±0.61mm3). The test group in the ITT set showed 13.05±1.25mm
(1.76±0.72mm3) and 13.40±1.82mm (1.87±0.77mm3), respectively (Table 2). However,
one test site of membrane perforation resulted in a significantly reduced volume of the
graft after 6 months (Figure 4B).
3. Histological Results
Samples from both groups showed similar patterns in bone formation within the
grafted area; newly formed bone could be observed extensively in the specimens that
were taken 10 or 12mm from the bottom adjacent to the floor of the preexisting bone
(Figure 5). These tissues appeared as non-lamellated woven bone that included large
numbers of osteocytes and an osteoid layer with linearly arranged osteoblasts, which
formed contact with the residual particles and a bridge to the adjacent mineralized tissue.
However, relatively larger particles of residual materials were found in the control sites
that received DBBM compared with the test sites of DPBM. Considering that
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biomaterials with the same range of initial particle size were used in both groups, the
particles might be degraded mechanically or biologically/chemically. Denser fibrotic
connective tissue occurred at the fibrovascular tissue area between the complexes of
mineralized tissue/residual materials in the control sites, whereas loose connective tissue
and multinucleated osteoclast-like cells could be found more frequently in the test sites
than the control sites (Figure 6). In the PP analysis, histometric measurements revealed
comparable new-bone formation (26.15±7.11% vs. 29.77±9.38% for the control and test
groups, respectively). Residual biomaterials were also comparable in the control and test
sites, but exceptionally one control site showed a significantly higher rate of residual
biomaterial (Figure 6G; 25.74±18.75% vs. 15.24±9.11%). Fibrovascular tissue was
observed similarly regardless of control/test group (48.11±12.69% vs. 54.99±12.00%).
Corresponding values for the test group in the ITT set were 27.95±10.33%, 15.40±8.53%,
and 56.64±12.28%, respectively (Table 2).
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IV. Discussion
The present clinical trial aimed to compare two biomaterials for maxillary sinus
grafting in the clinical, radiographic, and histological aspects. The bone quality on
histological samples from the augmented sites at 6 months after surgery was a primary
outcome value for this comparison, and the study design was based on the hypothesis that
sites receiving DPBM would not differ in bone regeneration compared with sites
receiving DBBM. The present results showed a comparable proportion of newly formed
bone on histological slides and similarly maintained volume in radiographies without any
clinical complications.
In the evaluation of biomaterials for sinus grafting, the clinical survival/success of
the dental implant is the most important issue for dental clinicians. In the present
clinical trial, all sites showed comparable clinical bone density during the site
preparation and successful initial stability of the dental implants. However, these values
were excluded as a comparable outcome in this clinical trial because a systematic
review of a meta-analysis reported limited evidence of the necessity of sinus bone
grafting instead of short implants in the aspect of clinical complications and dental
implant success (Esposito, et al., 2014). The short-term results of dental implants
installed in the augmented sinus might depend on the preexisting alveolar bone, rather
than the augmented area. However, the long-term results could be affected by the
success/failure of bone regeneration in the augmented sinus, particularly in cases with
15
severe marginal bone loss around the dental implant. Therefore, only histological bone
quality and radiographic bone quantity were selected in this clinical trial for the
comparison of the biomaterials DBBM and DPBM.
The majority of the previous clinical trials on sinus grafting used histologically
qualitative analysis as a primary outcome and showed similar ranges of newly formed
bone within the grafted area (20-35%) and residual biomaterials (15-35%) as the present
results, although these results were dependent on the experimental observational-period,
biopsy site, and particle size (Iezzi, et al., 2012; Kim, et al., 2015; Kolerman, et al., 2012;
Orsini, et al., 2006; Pagliani, et al., 2012). In the present histological results, comparable
bone formation occurred in the control and test sites (26.15±7.11 and 29.77±9.38%,
respectively), and also comparable biomaterials were remained except one control site
showing significantly higher rate of residual biomaterial (Figure 6). It resulted in higher
mean and variation of the control group without any statistical significance (25.74±18.75
and 15.24±9.11%; p=.18). Although the same sizes of particles were applied in both
groups, smaller-sized biomaterials were observed more frequently in test sites, which
suggested mechanical degradation during the clinical procedures or biological/chemical
degradation during the healing sequences. However, Testori et al. (Testori, et al., 2013)
histologically compared two particles-sizes of DBBM, which was the same biomaterial
used as the control in this study, and significantly decreased bone formation in sites
receiving smaller particles of DBBM was observed 6 to 8 months after surgery. This
result is contrary to the present result showing comparable bone formation and smaller
16
particles of residual biomaterials in the test site. Therefore, the present result could
support the resorption of DPBM with the bone formation in healing periods rather than
the mechanical pulverization during clinical application, which was also supported by the
frequently observed multinucleated cells in samples from the test group. However, these
results should be confirmed in further studies with longer-term experimental periods for
the aforementioned suggestion on this test biomaterial.
The volumetric stability of the augmented site is another important issue in sinus
grafting and is dependent on the characteristics of applied biomaterials such as the
resorption rates. The addition of autogenous or allogenous bone resulted in increased
volumetric shrinkage compared with the application of limited resorbable biomaterial
only, such as DBBM (Cosso, et al., 2014; Gorla, et al., 2015; Jensen, et al., 2012).
Therefore, considering the histologic/histometric results showing degraded sizes of
particles, the test biomaterial (DPBM) could be expected to show volumetric reduction
after 6 months. However, the test sites showed slightly increased volume of the
augmented sites, similarly to the control sites. The larger standard deviation in volume
maintenance on radiographic measurements in the test group might have originated as a
result of the exceptional case of membrane perforation. In one case of the test group, a
large-sized membrane perforation occurred and was completely closed by suturing
technique, although the site showed exceptionally reduced volume of the augmentation
after 6 months. With the exception of this case, all test sites showed comparable stability
on the augmented height/volume for 6 months.
17
Although this clinical trial showed noticeably comparable results of the test
biomaterial (DPBM) to the control biomaterial (DBBM) in histology and radiography, the
results should be interpreted conservatively for clinical uses. The appropriate sample size
was calculated as eight samples for each group for drawing a conclusion, but the control
group did not reach this sample size in both PP and ITT analysis because of higher drop-
out rates than expected in the initial study design. Within the limitation of this trial, the
similar results from both analyses of the ITT and PP sets suggest that DPBM might
produce comparable bone formation and volumetric stability with the DBBM in
maxillary sinus grafting for 6 months. However, further studies with longer-term periods
and larger sample sizes are warranted to confirm this conclusion.
18
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particle size on vital bone formation following maxillary sinus augmentation: a
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22
Figure Legends
Figure 1. Representative clinical photographs showing the procedures of laterally
approached sinus grafting; periosteal flap elevation (A), standardized window osteotomy
on the lateral wall of the maxillary sinus (B), window opening by detachment of the bony
fragment (C), sinus membrane elevation (D), grafting bone substitutes according to the
group assignment (E), and covering the bony window with a resorbable collagen
membrane (F).
Figure 2. Radiographic analysis by overlapping computed tomography (CT) images
from the time-points immediately and 6 months after surgery. Two serial CT images were
automatically overlapped using computer software and color-coded for disentangling
from each other (A). Linear and planimetric changes could be determined in the
overlapped images (B), and volumetric changes were measured by reconstruction of these
overlapped CT images.
Figure 3. Flow chart of this clinical trial: enrollment, randomization/group allocation,
sinus augmentation, and data analysis.
23
Figure 4. Representative radiographic results from the control and test groups (A). In
both groups, the volumes of the grafts were maintained and the radiopacity was more
intensified at 6 months compared with immediately after sinus grafting. Scatter plot of the
morphometric results of the linear and volumetric measurements (B) showing comparable
maintenance of the grafts in volume and height. A significantly reduced volume after 6
months could be found in one site from the test group, in which membrane perforation
occurred and was treated with suturing/applying collagen membrane.
Figure 5. Representative overall views of histological samples from the grafted sinuses.
Comparable bone formation could be found, although smaller particles of residual
biomaterials were found in the test sites compared with the control sites.
Figure 6. Representative histological photographs at high magnifications (A to F; A, C,
E from control and B, D, F from test group) and histomorphometric results. Newly
formed bone is shown on the surfaces of and between residual biomaterials in both
groups, although smaller sizes of residual particles are in the test site (A and B). In the
higher magnified views, woven bone was formed extensively around the residual
biomaterials (C and D), whereas limited bone formation and increased multinuclear cells
were observed at the area showing degraded small particles in both groups (E and F). The
histomorphometric results showed comparable bone formation within the grafted sinuses
but significantly reduced residual biomaterials (G).
24
Tables
Table 1. Demographics of patient population and maxillary sinus (mean ± SD).
Control Test (PP) Test (ITT)
Age 49.17 ± 1.33 40.83 ± 9.97 42.14 ± 9.74
Male/Female 7/0 5/3 6/3
Institute A/B 6/1 6/2 6/3
Right/Left 3/4 2/6 3/6
Pre-existing bone height, 3D (mm) 2.06 ± 0.43 1.90 ± 0.80 1.83 ± 0.78
25
Table 2. Measurements of radiographic and histometric analyzes (mean ± SD).
Control Test (PP) Test (ITT)
Surgery 6 months Surgery 6 months Surgery 6 months
Radiographic analyzes
Augmented
height, 3D (mm)
15.06
± 2.61
15.02
± 3.17
12.97
± 1.31
13.26
± 1.89
13.05
± 1.25
13.40
± 1.82
Augmented
volume (cc)
1.74
± 0.47
1.90
± 0.52
1.56
± 0.45
1.70
± 0.61
1.76
± 0.72
1.87
± 0.77
Histometric analyzes
Newly formed
bone (%) 26.15 ± 7.11 29.77 ± 9.38 27.95 ± 10.33
Residual
biomaterials (%) 25.74 ± 18.75 15.24 ± 9.11 15.40 ± 8.53
Fibrovascular
tissue (%) 48.11 ± 12.69 54.99 ± 12.00 56.64 ± 12.28
26
Figures
Figure 1
27
Figure 2
28
Figure 3
29
Figure 4
30
Figure 5
31
Figure 6
32
국문요약
탈단백 돼지뼈와 소뼈를 이용한 상악동거상술에 대한
무작위임상시험
<지도교수 조 규 성>
연세대학교 대학원 치의학과
신 현 기
탈단백우골은 과거부터 상악동거상술에 널리 사용되어 온 골이식재이며,
최근에는 탈단백저골이 탈단백우골을 대체할 수 있는 이종골 이식재로
생산되고 있다. 이 무작위임상시험의 목적은 상악동에 탈단백우골과
탈단백저골을 각각 이식한 후 조직학적 골질과 방사선학적 부피의 안정성을
비교하는 것이다.
총 16 명 환자의 20 개 상악동이 임상시험에 등록되어 무작위로 대조군과
시험군에 배정되었다. 대조군과 시험군의 상악동에는 각각 탈단백우골과
탈단백저골을 이식하였으며, 연구는 단일맹검으로 진행되어 모든 환자는
시험이 끝날 때까지 자신이 속한 군을 알 수 없었다. 수술은 상악동의 측벽에
표준화된 형태로 골삭제를 시행한 후, 상악동막을 거상하고 대조군과 시험군의
골이식재를 이식하는 방식으로 진행되었다. 수술 직후에 해당 부위에 대한
33
컴퓨터단층촬영을 시행하였고, 6 개월 후에는 컴퓨터단층촬영을 재시행하고
치과용 관상톱으로 조직생검을 진행하였다. 결과 분석은 일차적으로 조직학적인
골질을 평가하였으며, 이차적으로 3 차원으로 재건한 컴퓨터단층촬영에서
골이식재의 높이와 부피를 측정하였다.
임상시험 과정 중에 4 명이 중도 탈락하였고 1 명은 분석 과정에서
프로토콜 위반이 발견되어, 총 11 명 환자 (per-protocol 분석에서 15 개
상악동; intention-to-treat 분석에서 16 개 상악동)가 최종 분석에 포함되었다.
조직학적 분석에서 시험군은 신생골 형성과 잔존 이식재 양에 있어서
대조군과 비슷한 결과를 보였다. 그러나 대조군과 시험군에서 같은 입자
크기의 이식재를 적용했음에도 불구하고 대조군에 비해 시험군의 조직
슬라이드에서 잔존 이식재의 크기가 더 작은 것이 관찰되었다. 방사선학적
분석에서는 대조군과 시험군 모두 최소한의 높이와 부피의 변화를 보였다.
이상의 연구를 통해 상악동거상술에서 탈단백저골이 탈단백우골과 비슷한
골형성능과 부피 안정성을 보이는 것을 확인했다. 그러나 더 정확한 평가를
위해서는 더 많은 표본을 통한 더 긴 기간 동안의 임상시험이 필요할 것으로
사료된다.
핵심되는 말 : 상악동거상술, 탈단백저골, 탈단백우골, 무작위임상시험