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것 허락규약(Legal Code) 해하 쉽게 약한 것 니다.

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경 지. 하는 저 물 개 , 형 또는 가공할 수 없습니다.

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

ii

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.

iii

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

v

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

1

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;

2

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

3

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.

4

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,

5

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

6

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

8

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.

9

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.

10

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

11

(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

12

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

13

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).

14

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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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