OBJECTIVE MATERIALS AND METHODS RESULTS
Mechanical Stability of Collagen Membranes:
An In Vitro Study
Angelines Gasser1, Bastian Wessing2, Lizette Eummelen3, Anne Bühren3, and Hans Leemhuis3
Nobel Biocare AG, Zürich, Switzerland; 2Dental Practice Clinic Luisenhospital, Aachen, Germany; 3Matricel GmbH, Herzogenrath, Germany
Large horizontal or even minor vertical augmentations benefit from mechanically stable
resorbable membranes that can be fixated with pins to immobilize the graft material.1 A
prior investigation of native non-chemically cross-linked collagen membranes focusing
on differences in degradation behavior and tissue integration already indicated good
mechanical properties of a newly developed collagen membrane (CX).2 The aim of this study was (i) to compare the mechanical strength of commonly used
native non-chemically cross-linked (NXL) and chemically cross-linked (XL) collagen
membranes in vitro; (ii) to present an application of CX in a challenging clinical case of
a so-called “knife-edge-ridge” needing vertical and horizontal bone augmentation prior
to implant placement.
MATERIALS AND METHODS
IN VITRO STRENGTH ASSAYS
• Prior to all assays, 5 mm x 30 mm membrane samples (n=6 for each membrane)
were fully hydrated in phosphate-buffered saline at room temperature.
• Mechanical testing was performed using a Zwick/Roell Z2.5 tensile tester (Zwick/
Roell, Ulm, Germany) with a load cell (maximum range of 500 N). Jaw separation
was set at 10 mm. The strain rate was 12.5 mm/min for force and stress at break,
and 50 mm/min for suture retention. For stress at break, the mean thickness of each
membrane was used to calculate the cross-sectional area. For suture retention, a
surgical suture (USP 5-0, Polyamid 6 Ethylon II Blue, Johnson & Johnson Int., Belgium)
was placed 2 mm from the membrane border and tested as described previously.1
• Statistical analysis was performed using a Wilcoxon test with Bonferroni corrections
for multiple comparisons and significance was set at p<0.05. CX was the comparison
group for all statistical tests.
• A healthy 54 year old man had two long-time missing teeth at positions 46 and
• Clinical situation and panoramic x-ray showed a case of “knife-edge-ridge” (Lekholm
& Zarb classification C-D) (Figure 2-3).
• The residual bone on top of the nervus alveolaris inferior was 8 mm and 6 mm in
region 46 and 47, respectively.
GUIDED BONE REGENERATION (GBR) WITH THE CX COLLAGEN
MEMBRANE: CLINICAL CASE
• A GBR procedure was performed using the “tenting-screw-technique” and the CX
collagen membrane (Figure 4-7).
• Two 10 mm long osteosynthesis “tenting” screws were fixed in region 46 and 47 on
top of the ridge extending 6 mm above the bone.
• The composite bone graft of 50 % autologous bone chips and 50 % bovine bone mineral
(Bio-Oss®, Geistlich Pharma AG, Wolhusen, Switzerland) was placed (Figure 4).
• The CX membrane was fixed and stretched over the bone graft and the tenting
screws using two lingually- and three buccally-fixed titanium pins (Figure 5).
• 6 months after GBR horizontal bone gain was 8 mm while vertical bone gain was
• Two implants (NobelActive, Nobel Biocare AG, Kloten, Switzerland) were placed in
region 46 (11.5 mm x 4.3 mm) and 47 (10 mm x 5 mm) with insertion torque 70 Ncm
Figure 2: Alveolar ridge in
region 46, 47 with horizontal and
Figure 3: Panoramic radiograph
prior to the GBR procedure.
Figure 4: Bone graft placement
(initial vertical bone graft was 6 mm).
Figure 5: Bone graft successfully
immobilized through spanning and
fixation of the CX membrane.
Figure 6: Panoramic radiograph
after the GBR procedure.
Figure 7: Alveolar ridge after
6 months of healing, measuring 3 mm
vertical and 8 mm horizontal bone gain.
Figure 8: Implants placed in region
46 and 47 (one-stage procedure
using healing abutments).
Figure 9: Panoramic radiograph
after implant placement.
IN VITRO STRENGTH ASSAYS (FIGURE 1)
• CX demonstrated the highest force at break wet (21.2 N; interquartile range [IQR]:
• CX showed the highest stress at break wet (14.2 N/mm2; IQR: 9.1-16.3).
• CX had the highest suture retention wet (6.1 N; IQR: 5.9-6.5).
• In general, NXL membranes had a higher force at break wet and a higher stress at
break wet in comparison to XL membranes.
Figure 1: Wet CX membrane demonstrated the highest force at break (top panel),
the highest stress at break (middle panel) and the highest suture retention (bottom
panel). Values are plotted as means with error bars representing standard deviation.
* denotes statistical significance (p<0.05) in comparison to CX.
Force at break wet
Suture retention wet
Stress at break wet
Wet creosTM xenoprotect membrane has a higher mechanical strength, resists higher
stress and demonstrates a higher suture pull-out force than all other tested non crosslinked and cross-linked collagen membranes. These mechanical characteristics suggest
that creosTM xenoprotect can provide an important tool in extensive guided bone
regeneration such as horizontal ridge augmentation.
Non cross-linked collagen membranes (NXL)
CX: creos xenoprotect [Nobel Biocare]
CO: Copios [Zimmer]
JS: Jason [botiss]
OF: Osseoguard Flex [3i]
BG: Bio-Gide [Geistlich]
Cross-linked collagen membranes (XL)
BE: BioMend Extend [Zimmer]
ML: Mem-Lok [BioHorizons]
OP: OssixPlus [Datum Dental]
BM: BioMend [Zimmer]
CY: Cytoplast RTM [Osteogenis]
1.Wessing B, et al. Horizontal ridge augmentation with a novel resorbable collagen
membrane: A retrospective analysis of 36 consecutive patients. Int J Periodontics
Restorative Dent 2016;36:179-187.
2.Bozkurt A, et al. Differences in degradation behavior of two non-cross-linked collagen
barrier membranes: an in vitro and in vivo study. Clin. Oral Impl. Res. 2014;25(12):1403-11.
This study was jointly sponsored by Matricel and Nobel Biocare
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