Post by barnydhppy on May 23, 2011 16:50:41 GMT -5
Collagen
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Collagen membrane and open healing - a predictable therapeutic option?
Pascal Valentini, Paris
The outstanding handling characteristics of natural collagen membranes have
simplified the operative technique in implant surgery. Thanks to the good woundhealing
properties of these materials, it has also been possible to improve the
prognosis of immediate implants. Open healing is being increasingly discussed as a
new option for the application of collagen membranes. Cases from private practice
show positive and promising results, though adequate scientific documentation is not
yet available.
The surgical technique has been simplified by employing materials made of natural collagen
as barrier membranes for bone regeneration. Thanks to the resorbability of the collagen,
there is no need to perform a second operation for removal of the membrane, as is
necessary with non-resorbable e-PTFE [polytetrafluoroethylene] membranes. The
resorbability of collagen membranes also has advantages with a two-stage procedure
(augmentation, and implantation 4-6 months later). The re-opening can be performed with a
considerably smaller muco-periosteal flap, thus giving greater protection for the soft tissue
and the newly-formed bone.
In contrast to the synthetic polymer membranes now in use, natural untreated collagen
membranes are strongly hydrophilic and adhere lightly to the walls of the defect. Additional
fixation by means of pins or suture material can therefore often be dispensed with when the
morphology and position of the defect are favourable.
Wound-healing properties of collagen
Natural collagen membranes exert a positive influence on tissue integration and wound
healing. Postoperative membrane exposures develop less often than with non-resorbable
teflon membranes and generally heal up without problems1 2.. This can presumably be
attributed to the fact that collagen
!" acts chemotactically on fibroblasts3 and thus promotes primary wound closure
!" is a haemostatic4 and thus acts to promote and stabilise blood-clot formation
!" promotes cellular proliferation, migration and adhesion5 .
On the basis of these advantages, suitable collagen membranes are employed by many
practices in combination with bone replacement as the standard treatment for bone defects
in implantology.
At present in implantology and periodontology, a whole series of different collagen
membranes are available, some of which clearly differ with regard to their fibrous structure,
collagen type, breakdown kinetics, chemical additives, cross-linkage, and number of
supporting scientific studies. It is known, for instance, that differences in cross-linkage exert
a relevant influence on the biological behaviour and on the biocompatibility of these
materials for the patient5. The basis for selecting a membrane should always be the
available scientific documentation from independent centres.
GBR- membrane with natural three-dimensional fibrous structure
Bio-Gide (Geistlich Pharma Ltd, Wolhusen, Switzerland) is a collagen membrane
comprehensively described in the implantology literature 1 2 6 7 8 . The membrane consists
of natural collagen, types I and III (obtained from pigs) without additional cross-linkage or
chemical additives. It possesses two layers: The compact layer consists of fine collagen
2
mesh, which performs the barrier function of the membrane. The porous layer consists of a
three-dimensional fibrous structure and therefore permits the integration of newly formed
tissue into this matrix. The barrier function of the membrane is stated to last 4-6 months.
Various independent animal and human studies confirm the good bone regeneration which
can be attained by using this membrane in combination with bone replacement material 1 2 6 .
_______________________________________________________________
Fig. Bio-Gide, two-layer design, cross-section in SEM [scanning electron-microscope] x 100.
The compact cell-occluding layer performs the barrier function and serves as a guide rail for
soft-tissue. The porous side of the membrane is a three-dimensional collagen matrix, which
facilitates cellular integration.
_______________________________________________________________
The first long-term results of controlled bone regeneration using a collagen membrane (Bio-
Gide) were recently published 9 . The data from this prospective, comparative study show
that the 5-year survival rate of implants which had been inserted with or without boneregenerative
measures were equal. The implant survival rates in defects treated with Bio-
Gide and e-PTFE membrane (combined in each case with Bio-Oss) did not differ.
The good biocompatibility and promotion of wound healing of the natural collagen
membrane have also been described in various publications 1 2 8 .
Improved prognosis with immediate implants
These positive wound-healing properties of natural collagen membranes in implantology
have improved the prognosis of immediate implantation into fresh extraction-sockets. Since
the wound after tooth extraction cannot usually be closed without tension, an increased risk
of postoperative membrane dehiscence must generally be anticipated. As shown by a
clinical study1 membrane exposure actually develops within the first 6 weeks in 60% of
immediate implants treated with non-resorbable e-PTFE membranes. By contrast, only 12%
of the immediate implants covered with Bio-Gide showed wound dehiscence, which healed
up again by itself. Filling of the defect amounted to 95% for the immediate implants covered
with Bio-Gide, and to 85% for those treated with e-PTFE.
Open healing of collagen membranes - an advantage?
Such positive results could form the foundation-stone for the development of new fields of
application. Open healing of collagen membranes has been discussed by practitioners for
some time as a therapeutic option where insufficient soft-tissue is available. Instead of
closing the wound under tension with the aid of periosteal slitting and flap mobilisation, and
thus running the risk of subsequent membrane exposure, a suitable membrane can heal in
3
without complete wound closure - in a degree of controlled exposure. Appropriate after-care
of the wound must in any event be carried out by the patient from the beginning. Clinical
experience with Bio-Gide membranes in private practice so far shows that this therapeutic
option is possible under suitable conditions (Figs. 1-7). The open wound above the
membrane healed up completely within 6 weeks in the case illustrated. Resorption of the
exposed membrane may possibly be accelerated by applying one or two additional layers of
membrane (e.g. off-cuts of the same material).
Open healing - open questions
Even though the practical experience with individual cases in private practice is very
promising, the prognosis of this application has scarcely been evaluated in scientific studies
to date. Among other questions, the result of bone regeneration and of the soft-tissue
appearances have yet to be clarified here. Even the possible accelerated resorption of the
exposed collagen or its prevention by multi-layered membrane application are assumptions
which require scientific verification. Until university studies have clarified such questions,
complete wound closure should remain the treatment of choice.
_______________________________________________________________
Captions
Fig. 1. Immediate implantation after extraction. Buccal discrepancy between implant and
diameter of socket. Opening up by sulcus incision without periosteal splitting.
Fig. 2. Filling of the bone defect with Bio-Oss prevents resorption of the aesthetically
important buccal wall.
4
Fig. 3. The collagen membrane (Bio-Gide) placed over the defect is left open, not covered
with the flap. The patient is advised to clean the wound after each meal with a very soft
toothbrush (with chlorhexidine).
Fig. 4. 1 week postoperatively, suture removal, stable clot.
Fig. 5. 2 weeks postoperatively, onset of wound healing.
Fig. 6. 4 weeks postoperatively, onset of epithelialisation.
5
Fig. 7. 6 weeks postoperatively, complete wound healing.
Fig. 8. Re-opening after 6 months, complete bony healing of defect.
Fig. 9. Even with open healing in of the membrane, the desired bone volume was attained.
6
1 Zitzmann NU, Naef R, Schärer P.
Resorbable versus nonresorbable membranes in combination with Bio-Oss® for guided bone
regeneration. Int J of Oral & Maxillofacial Implants 1997;12:844-852.
2 Hürzeler MB, Weng D, Hutmacher D.
Bone regeneration around implants: a clinical study with a new resorbable membrane.
Deutsche Zahnärztliche Zeitschrift 1996; 51. Jahrgang, 5.
3 Postlethwaite AE, Seyer JM, Kang AH. Chemotactic attraction of human fibroblasts to type I, II, and
III collagens and collagen-derived peptides. Proc. Natl. Acad. Scie. 1978;75:871 – 875.
4 Wagner WR, Pachence JM, Ristich J, Hohnson PC. Comparative in vitro analysis of topical
hemostatic agents. J Surg Res 1996; 6:100 – 108.
5 Bunyaratevej P, Wang HL Collagen Membranes: A Review. J Periodontol 2001; 72:215 – 229.
6 Hürzeler MB, Kohal RJ, Naghshbandi J, Mota LF, Conradt J, Hutmacher D, Caffesse RG
Evaluation of a new bioresorbable barrier to facilitate guided bone regeneration around exposed
implant threads. Int J Oral Maxillofac Surg 1998;27:315-320.
7 Hockers T, Abensur D, Valentini P, Legrand R, Hämmerle CH.
The combined use of bioresorbable membranes and xenografts or autografts in the treatment of
bone defects around implants. A study in beagle dogs: Clin. Oral Impl. Res 1999;10:487-498.
8 Kay S, Wisner-Lynch L, Marxer M, Lynch SE.
Guided bone regeneration: Integration of Resorbable Membrane and a bone graft material.
The Regeneration Report 1997; 9:185-194.
9 Zitzmann N, Schärer P, Marinello C.
Long-term Results of Implants Treated with Guided Bone Regeneration: A 5-year Prospective Study.
Int J Oral Maxillofac Implants 2001;16:355-366.
**To view the figures mentioned in this article, you will need to go to the site.***
*****************************************************
Collagen membrane and open healing - a predictable therapeutic option?
Pascal Valentini, Paris
The outstanding handling characteristics of natural collagen membranes have
simplified the operative technique in implant surgery. Thanks to the good woundhealing
properties of these materials, it has also been possible to improve the
prognosis of immediate implants. Open healing is being increasingly discussed as a
new option for the application of collagen membranes. Cases from private practice
show positive and promising results, though adequate scientific documentation is not
yet available.
The surgical technique has been simplified by employing materials made of natural collagen
as barrier membranes for bone regeneration. Thanks to the resorbability of the collagen,
there is no need to perform a second operation for removal of the membrane, as is
necessary with non-resorbable e-PTFE [polytetrafluoroethylene] membranes. The
resorbability of collagen membranes also has advantages with a two-stage procedure
(augmentation, and implantation 4-6 months later). The re-opening can be performed with a
considerably smaller muco-periosteal flap, thus giving greater protection for the soft tissue
and the newly-formed bone.
In contrast to the synthetic polymer membranes now in use, natural untreated collagen
membranes are strongly hydrophilic and adhere lightly to the walls of the defect. Additional
fixation by means of pins or suture material can therefore often be dispensed with when the
morphology and position of the defect are favourable.
Wound-healing properties of collagen
Natural collagen membranes exert a positive influence on tissue integration and wound
healing. Postoperative membrane exposures develop less often than with non-resorbable
teflon membranes and generally heal up without problems1 2.. This can presumably be
attributed to the fact that collagen
!" acts chemotactically on fibroblasts3 and thus promotes primary wound closure
!" is a haemostatic4 and thus acts to promote and stabilise blood-clot formation
!" promotes cellular proliferation, migration and adhesion5 .
On the basis of these advantages, suitable collagen membranes are employed by many
practices in combination with bone replacement as the standard treatment for bone defects
in implantology.
At present in implantology and periodontology, a whole series of different collagen
membranes are available, some of which clearly differ with regard to their fibrous structure,
collagen type, breakdown kinetics, chemical additives, cross-linkage, and number of
supporting scientific studies. It is known, for instance, that differences in cross-linkage exert
a relevant influence on the biological behaviour and on the biocompatibility of these
materials for the patient5. The basis for selecting a membrane should always be the
available scientific documentation from independent centres.
GBR- membrane with natural three-dimensional fibrous structure
Bio-Gide (Geistlich Pharma Ltd, Wolhusen, Switzerland) is a collagen membrane
comprehensively described in the implantology literature 1 2 6 7 8 . The membrane consists
of natural collagen, types I and III (obtained from pigs) without additional cross-linkage or
chemical additives. It possesses two layers: The compact layer consists of fine collagen
2
mesh, which performs the barrier function of the membrane. The porous layer consists of a
three-dimensional fibrous structure and therefore permits the integration of newly formed
tissue into this matrix. The barrier function of the membrane is stated to last 4-6 months.
Various independent animal and human studies confirm the good bone regeneration which
can be attained by using this membrane in combination with bone replacement material 1 2 6 .
_______________________________________________________________
Fig. Bio-Gide, two-layer design, cross-section in SEM [scanning electron-microscope] x 100.
The compact cell-occluding layer performs the barrier function and serves as a guide rail for
soft-tissue. The porous side of the membrane is a three-dimensional collagen matrix, which
facilitates cellular integration.
_______________________________________________________________
The first long-term results of controlled bone regeneration using a collagen membrane (Bio-
Gide) were recently published 9 . The data from this prospective, comparative study show
that the 5-year survival rate of implants which had been inserted with or without boneregenerative
measures were equal. The implant survival rates in defects treated with Bio-
Gide and e-PTFE membrane (combined in each case with Bio-Oss) did not differ.
The good biocompatibility and promotion of wound healing of the natural collagen
membrane have also been described in various publications 1 2 8 .
Improved prognosis with immediate implants
These positive wound-healing properties of natural collagen membranes in implantology
have improved the prognosis of immediate implantation into fresh extraction-sockets. Since
the wound after tooth extraction cannot usually be closed without tension, an increased risk
of postoperative membrane dehiscence must generally be anticipated. As shown by a
clinical study1 membrane exposure actually develops within the first 6 weeks in 60% of
immediate implants treated with non-resorbable e-PTFE membranes. By contrast, only 12%
of the immediate implants covered with Bio-Gide showed wound dehiscence, which healed
up again by itself. Filling of the defect amounted to 95% for the immediate implants covered
with Bio-Gide, and to 85% for those treated with e-PTFE.
Open healing of collagen membranes - an advantage?
Such positive results could form the foundation-stone for the development of new fields of
application. Open healing of collagen membranes has been discussed by practitioners for
some time as a therapeutic option where insufficient soft-tissue is available. Instead of
closing the wound under tension with the aid of periosteal slitting and flap mobilisation, and
thus running the risk of subsequent membrane exposure, a suitable membrane can heal in
3
without complete wound closure - in a degree of controlled exposure. Appropriate after-care
of the wound must in any event be carried out by the patient from the beginning. Clinical
experience with Bio-Gide membranes in private practice so far shows that this therapeutic
option is possible under suitable conditions (Figs. 1-7). The open wound above the
membrane healed up completely within 6 weeks in the case illustrated. Resorption of the
exposed membrane may possibly be accelerated by applying one or two additional layers of
membrane (e.g. off-cuts of the same material).
Open healing - open questions
Even though the practical experience with individual cases in private practice is very
promising, the prognosis of this application has scarcely been evaluated in scientific studies
to date. Among other questions, the result of bone regeneration and of the soft-tissue
appearances have yet to be clarified here. Even the possible accelerated resorption of the
exposed collagen or its prevention by multi-layered membrane application are assumptions
which require scientific verification. Until university studies have clarified such questions,
complete wound closure should remain the treatment of choice.
_______________________________________________________________
Captions
Fig. 1. Immediate implantation after extraction. Buccal discrepancy between implant and
diameter of socket. Opening up by sulcus incision without periosteal splitting.
Fig. 2. Filling of the bone defect with Bio-Oss prevents resorption of the aesthetically
important buccal wall.
4
Fig. 3. The collagen membrane (Bio-Gide) placed over the defect is left open, not covered
with the flap. The patient is advised to clean the wound after each meal with a very soft
toothbrush (with chlorhexidine).
Fig. 4. 1 week postoperatively, suture removal, stable clot.
Fig. 5. 2 weeks postoperatively, onset of wound healing.
Fig. 6. 4 weeks postoperatively, onset of epithelialisation.
5
Fig. 7. 6 weeks postoperatively, complete wound healing.
Fig. 8. Re-opening after 6 months, complete bony healing of defect.
Fig. 9. Even with open healing in of the membrane, the desired bone volume was attained.
6
1 Zitzmann NU, Naef R, Schärer P.
Resorbable versus nonresorbable membranes in combination with Bio-Oss® for guided bone
regeneration. Int J of Oral & Maxillofacial Implants 1997;12:844-852.
2 Hürzeler MB, Weng D, Hutmacher D.
Bone regeneration around implants: a clinical study with a new resorbable membrane.
Deutsche Zahnärztliche Zeitschrift 1996; 51. Jahrgang, 5.
3 Postlethwaite AE, Seyer JM, Kang AH. Chemotactic attraction of human fibroblasts to type I, II, and
III collagens and collagen-derived peptides. Proc. Natl. Acad. Scie. 1978;75:871 – 875.
4 Wagner WR, Pachence JM, Ristich J, Hohnson PC. Comparative in vitro analysis of topical
hemostatic agents. J Surg Res 1996; 6:100 – 108.
5 Bunyaratevej P, Wang HL Collagen Membranes: A Review. J Periodontol 2001; 72:215 – 229.
6 Hürzeler MB, Kohal RJ, Naghshbandi J, Mota LF, Conradt J, Hutmacher D, Caffesse RG
Evaluation of a new bioresorbable barrier to facilitate guided bone regeneration around exposed
implant threads. Int J Oral Maxillofac Surg 1998;27:315-320.
7 Hockers T, Abensur D, Valentini P, Legrand R, Hämmerle CH.
The combined use of bioresorbable membranes and xenografts or autografts in the treatment of
bone defects around implants. A study in beagle dogs: Clin. Oral Impl. Res 1999;10:487-498.
8 Kay S, Wisner-Lynch L, Marxer M, Lynch SE.
Guided bone regeneration: Integration of Resorbable Membrane and a bone graft material.
The Regeneration Report 1997; 9:185-194.
9 Zitzmann N, Schärer P, Marinello C.
Long-term Results of Implants Treated with Guided Bone Regeneration: A 5-year Prospective Study.
Int J Oral Maxillofac Implants 2001;16:355-366.
**To view the figures mentioned in this article, you will need to go to the site.***