Histomorphometric and Cone Beam Computed Tomography Assessments on the Influence a Collagen Membrane Placed Subjacent the Sinus Mucosa After Maxillary Sinus Floor Augmentation. A Randomized Clinical Trial.
Phase: NA
Conditions: Alveolar Bone Loss
Sponsor: ARDEC Academy

Histomorphometric 
and 
cone 
beam 
computed 
tomography assessments on the influence a collagen 
membrane placed subjacent the sinus mucosa after 
maxillary sinus floor augmentation. A randomized clinical 
trial.  
  
Authors   
Dr. Atsuya Hirota, DDS, Doctor, Osaka Dental University, Osaka, Italy  
Dr. Shigeo Fujiwara, DDS, Doctor, ARDEC Academy, Rimini, Italy 
Dr. Mauro Ferri, DDS, Doctor, Corporación Universitaria Rafael Núñez, Cartagena 
de Indias, Colombia  
Karol Alí Apaza Alccayhuaman, DDS, ARDEC Academy, Rimini, Italy  
Niklaus Peter Lang, DDS, PhD, Center for Dental Medicine, University of Zurich,  
Zurich, Switzerland   
Daniele Botticelli, BMBD, dentist, PhD, ARDEC Academy, Rimini, Italy  
Dr. Natalia Fortich Mesa, DDS, Doctor, Corporación Universitária Rafael Núñez, 
Cartagena de Indias, Colombia  
  
Corresponding author:   
Dott. Karol Alí Apaza Alccayhuaman, DDS, ARDEC Academy, Viale Giovanni  
Pascoli 67 – 47923 RIMINI (ITALY) Tel.-Fax: +39 0541 393444   
E-mail: caroline7_k@hotmail.com  
  
Cartagena de Indias, April 4th, 2016  
        
  
Conflict of Interest Statement  
The authors declare no conflict of interest regarding this study.  

Tecnoss srl, Giaveno, Italy will provide all biomaterials. Sweden & Martina SRL, Due 
Carrare, Padua, Italy and ARDEC Academy, Ariminum Odontologica s.r.l., Rimini, Italy will 
cover the costs of the study.  
   
  
 
  
  
  
 

Abstract  
Aim: to seek for differences in osseointegration at implants and dimensional 
variations of augmented maxillary sinuses with or without the placement of a 
collagen membrane subjacent the sinus mucosa.  
Material and Methods: After the elevation of the maxillary sinus mucosa, a 
collagen membrane with standard dimensions will be placed at the test sites 
subjacent the sinus mucosa and the elevated space will be filled with a xenograft, 
both test and control groups. A collagen membrane will be placed to cover the 
antrostomy at both groups and sutures will be provided to close the wound. After 
six months of healing, mini-implants will be installed. After 9 months, biopsies 
containing the mini-implants will be harvested for histomorphometric analyses. 
CBCTs will be taken for all patients before surgery (T0), after 1 week from sinus 
floor augmentation (T1) and after 9 months of healing (T2). Osseointegration of the 
mini-implants and dimensional changes over time of soft and hard tissues will be 
evaluated on the CBCTs. 
 

Introduction  
The perforation of the sinus mucosa during sinus floor augmentation is a  
complication that has been reported in several clinical1-4 and experimental 
studies5,6 with an occurrence that varies between 10 and 55%. Dislodgement of the 
biomaterial and sinusitis may represent a consequence of the perforation.2 Small 
perforations may not require any treatment because, after the elevation and 
relaxation of the sinus mucosa, the margin of the perforation may collapse together 
and close the defect.7 Perforations of larger dimensions may be closed using 
sutures1,8,9 or fibrin glue.1,8,10 Collagen membranes were also used to protect the  
perforations of the sinus mucosa and good outcomes have been claimed.3,4,11-16  
Several experimental studies have bene performed to evaluate histologically the 
influence of a collagen membrane placed subjacent the sinus mucosa in the 
absence5,16 or presence of perforation17 and no differences were seen in the 
healing outcomes. However, there is still a lack of clinical information about how 
the placement of a collagen membrane between the sinus mucosa and the graft 
may influence the osseointegration of implants and the dimensional variations and 
healing at augmented maxillary sinuses. Hence, the aim of this randomized clinical 
trial will be to seek for differences in osseointegration at implants and dimensional 
variations of augmented maxillary sinuses with or without the placement of a 
collagen membrane subjacent the sinus mucosa.  
  
Material and methods   
The protocol was approved by the Ethical Committee of the University Corporation  

Rafael Núñez, Cartagena de Indias, Colombia (protocol #03-2015; 4 December 
2015) and the Declaration of Helsinki on medical protocols and ethics will be 
followed. This study will be submitted for registration to ClinicalTrials.gov PRS 
(https://clinicaltrials.gov) to obtain the NCT. The patients will be informed about the 
procedures and the possible complications and signed informed consents will be 
obtained. 
The 
Consort 
checklist 
will 
be 
followed 
for 
this 
study 
(http://www.consortstatement.org/).  
Study population   
For the present randomized clinical trial, all recruitments, surgeries and follow-ups 
will be carried out at the University Corporation Rafael Núñez, in Cartagena de 
Indias (Colombia). To calculate the sample size, the data from an article that 
assessed the variations over time in height of the augmented sinuses were used.18 
It was calculated that an n=10 was sufficient to show differences, if exist. An author 
not involved in the surgeries will perform the randomization process (MF). The 
assignments will be sealed within opaque envelopes that will be opened after the 
completion of the elevation of the sinus mucosa.  
The following inclusion criteria have to be fulfilled:   
(i) 
presence of an edentulous atrophic zone in the posterior segment of the 
maxilla;  
(ii) 
height of the sinus floor ≤4 mm;   
(iii) 
desiring a prosthetic restoration of the zone using a fix prosthesis supported 
by implants;   
(iv) 
≥ 21 years of age;   

(v) 
good general health;   
(i) 
no contraindication for oral surgical procedures;   
(ii) 
not being pregnant.   
The patients will be excluded if they:   
(iii) 
present a systemic disordered;   
(iv) 
had a chemotherapic or radiotherapeutic treatment;   
(v) 
are smokers >10 cigarettes per day;   
(vi) 
have an acute or a chronic sinusitis;   
(vii) 
had a previous bone augmentation procedures in the zone of interest.  
Biomaterial used  
The filler material will be a collagenated corticocancellous porcine bone granules 
(Gen-Os, 250–1000 µm, OsteoBiol, Tecnoss, Giaveno, Italy).  
The membrane used subjacent the sinus mucosa at the test sites and to cover the 
antrostomy at both test and control sites the control sites will be an equine collagen 
membrane (Evolution, 0.3 mm, OsteoBiol, Tecnoss).  
Clinical procedures  
The lateral wall of the maxillary sinus will be exposed and osteotomies of about 6 
mm in height and 10 mm long will be prepared using a diamond insert (SFS 109 
029), Komet-Brasseler-GmbH, Germany) mounted on a sonic-air surgical 
instrument (Sonosurgery® TKD, Calenzano, Fi - Italy). The sinus mucosa will be 
elevated and, at the test sites, a collagen membrane will be placed subjacent the 
sinus mucosa. Subsequently, the elevated space will be filled with the xenograft 

both at the test and control sites. A collagen membrane will be used to protect the 
antrostomies and the soft tissues wounds will be sutured. 
After 6 months of healing, a mini-implant 2.4 mm of diameter and 8 mm of length 
(Sweden & Martina, Due Carrare, Padua, Italy), with a moderately rough surface 
(ZirTi, Sweden & Martina, Due Carrare, Padua, Italy) will be installed in the 
elevated area. After three months, the mini-implants were retrieved with custom-
made trephine (GA33M, Bontempi Strumenti Chirurgici, San Giovanni in 
Marignano, RN, Italy), 3.5 mm and 4 mm of internal and external diameter, 
respectively. An eccentric method for retrieving biopsies was adopted and the 
specimens were fixed in 10% buffered formalin. A definitive implant will be installed 
in the site of the biopsy retrieval. 
Amoxicillin 875 mg with clavulanic acid 125 mg twice a day for 6 days, nonsteroidal 
anti-inflammatory drugs as needed, and mouth rinses with 0.12% chlorhexidine 
three times a day for 10 days will be recommended after each surgery. The sutures 
will be removed after 7 days, and the patients will be enrolled in a maintenance 
program for the full extent of the study.  
Histological preparation of the biopsies 
The specimens will be dehydrated in an ascending series of alcohol and then 
included in a glycol-methacrylate resin (Technovit® 7200 VLC; Kulzer, Wehrheim, 
Germany) and polymerized. The biopsies were sectioned according to the 
longitudinal axis of the mini-implant, obtaining specimens of about 150 microns of 
width that were subsequently ground to about 30 µm of width. The staining will be 
performed with acid fuchsine and toluidine blue. 

The Results Data Element Definitions for histomorphometric analyses  
The histomorphometric evaluations will be performed at the ARDEC Academy 
facilities (Rimini, Italy) using an Eclipse Ci microscope (Nikon Corporation, Tokyo, 
Japan) connected to a digital video camera (Digital Sight DS-2Mv, Nikon 
Corporation, Tokyo, Japan). All histomorphometric evaluation will be performed 
x200 magnification from the most coronal to the most apical contact of the bone to 
the implant surface using the software NIS-Elements D 5.11 (Laboratory Imaging, 
Nikon Corporation, Tokyo, Japan).  
 
Outcomes measures for the histomorphometric analyses 
Primary outcome: New bone-to-implant contact  
Description: Measurements will be assessed between the most coronal (B) and the 
most apical (A) contacts of new bone to the implant surface. 
Timeframe: Mini-implants will be installed six months after sinus lifting and retrieved 
after three months of healing. 
 
Secondary outcome: New bone density around the mini-implant, from B to A and 
up to a distance of 400 µm from the implant surface. 
Description: Measurements will be assessed using a point counting procedure, 
superposing a lattice with squares of 50 µm over the histological image. 
Timeframe: Mini-implants will be installed six months after sinus lifting and retrieved 
after three months of healing. 
 

Other pre-specified outcomes for histometric assessments: old-bone (pre-existing), 
marrow bone and residual xenograft. 
Description: Measurements will be assessed between the most coronal (B) and the 
most apical (A) contacts of new bone to the implant surface  
Timeframe: Mini-implants will be installed six months after sinus lifting and retrieved 
after three months of healing. 
 
Other pre-specified outcomes for morphometric assessments: old-bone (pre-
existing), marrow bone, residual xenograft, and vessel. 
Description: Measurements will be assessed using a point counting procedure, 
superposing a lattice with squares of 50 µm over the histological image. 
Timeframe: Mini-implants will be installed six months after sinus lifting and retrieved 
after three months of healing. 
Comparisons among test (membrane sites) and control groups will be performed.  
 
CBCT imaging procedures  
Cone bean computed tomographies (CBCTs) will be taken at three different 
periods: before the sinus floor elevation (T0); one week (T1) and 9 months (T2) 
after surgery.  
  
CBCT imaging analyses  
All radiographic evaluations will be performed with the software i-Dixel 2.0 (J. 
Morita Corporation, Kyoto, Japan). As references, a line drew following the floor of 

the nose will be used both in the coronal view (axis X) and in the lateral view (axis 
Z).   
  
The Results Data Element Definitions for CBCTs 
The following parameters will be evaluated: mucosa thickness, bone crest height, 
nasal floor height from the base of the sinus, superior posterior alveolar artery 
height and diameter, sinus width, distance between the inferior margin of the 
antrostomy and the base of the sinus, antrostomy height, sinus length in the lateral 
view, the largest length of the xenograft/ hard tissue in the lateral view.   
The variation in height and area of the elevated region will be evaluated among the 
CBCT taken in the various periods of healing  
  
Outcomes measures for the CBCTs analyses 
Primary outcome: Changing in height of the elevated zone.  
Description: Measurements will be assessed in the medial, middle and lateral 
regions of the elevated zone using the cone beam computerized tomographies 
(CBCTs) taken in various periods. Comparisons among the CBCTs of each  
participants will be performed.  
Timeframe: The CBCTs will be taken before surgery (T0) and 1-week (T1) and 9 
months (T2) after surgery.  
Secondary outcome: Changing in mucosa thickness.  
Description: Measurements will be assessed in the cone beam computerized 
tomographies (CBCTs) taken in various periods. Comparisons among the CBCTs 
of each participant will be performed.  

Timeframe: The CBCTs will be taken before surgery (T0) and 1-week (T1) and 9 
months (T2) after surgery.  
Other pre-specified outcomes: (C-F) bone crest height, (X-F) nasal floor height, 
(AC) anastomosis height and (AD) its diameter, (XW) sinus width, (LM-F) balcony 
height, (LM-UM) window height, (ZW) sinus length, (ZE) the largest length of the 
xenograft/ hard tissue, T0 X-area and T0 Z-area.  
Description: Measurements will be assessed in the medial, middle and lateral 
regions of the elevated zone using the cone beam computerized tomographies 
(CBCTs) taken in various periods. Comparisons among the CBCTs of each  
participants will be performed.  
Timeframe: The CBCTs will be taken before surgery (T0) and 1-week (T1) and 9 
months (T2) after surgery.  
  
Data analysis  
The histomorphometric and radiographic measurements will be performed twice by 
well-trained researchers that will be blinded about the differences in the protocols. 
Mean values will be obtained between the two measurements and used for 
analyses.  
Mean values and standard deviations (SD) will be calculated for each outcome 
variable. Differences between the groups will be analyzed using the Mann-Whitney 
test. The level of significance will be set at α=0.05. 
  
  

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