poMetrafluaroethylene (PTFE) suture (Gore-Tex Suture, Gore gc remec.cal.com) (Figure 6). After 10 weeks of healing, the patient returned for surgical unccvery ...
CASE REPORT GUIDED BONE REGENERATION
Use of a Sugar Cross-Linked Collagen Membrane Offers Cell Exclusion and Ossification Barry P. Levin, DMD; and Yuval Zubery, DMD
Abstract: Resorbable barrier membranes are advantageous for use in guided bone regeneration for treatment of peri-implant defects, eliminating the need for surgical re-entry. Ribose, a na tural sugar-based materi al that has been used to cross-link collagen, is able to be utilized in high concentrations to extend barrier function for long periods without eliciting inflammation or foreign body reactions in situ. A unique finding with a ribose cross-linked collagen membrane is the in situ ossification of the material upon re-entry. This article presents two cases that clinically demonstrate the efficacy of a sugar cross-linked collagen membrane in peri-implant and site development type defects and suggest its ability to ossify and achieve bone regeneration.
linicians have used guided bone regeneration (GBR) break down in situ is extended.6 Through different chemical and physical proprietary processes, attempts are being made to cross as a technique for treatment of peri-implant defects for decades.1This concept of soft-tissue cell exclu link collagen devices to increase their in vivo life in the tissue. For sion, facilitating selective cell migration and differ example, the cross-linking of several barriers is being done using entiation, was derived from periodontal research.2'3 harsh chemicals, such as glutaraldehydes. Because these chemi cals are toxic in high concentration, the amount of cross-linking The original membrane designed for periodontal and peri-implant defect therapy was nonresorbable and required a second surgi is intentionally limited to avoid adverse tissue reactions that may cal procedure to remove the material.1This fortuitously provided negatively affect the regenerative outcomes. Another material used to cross-link collagen is a natural sugar, surgeons an opportunity, however, to evaluate the amount, or lack thereof, of defect resolution/thread coverage. Although this manda ribose. The process of glycation closely replicates the manner in tory re-entry was accepted as standard therapy, the disadvantages which collagen fibrils are cross-linked in the body.7Being a natural sugar, this material can be used in high concentration that is ca of it included increased patient morbidity and bone loss associated pable of extending barrier function for long periods of time without with full-thickness flap reflection. This led to the development of resorbable barrier membranes. eliciting inflammation or foreign body reactions in situ. Klinger et al demonstrated greater resistance to breakdown The obvious advantages of these biomaterials include the elimina with ribose cross-linked collagen membranes after 10 days of tion of surgical re-entries to remove the membranes and better bone exposure to the oral cavity compared to noncross-linked and preservation after regeneration has occurred. Synthetic and natural glutaraldehyde cross-linked collagen m embranes.8 In a com polymers have been used for these purposes. Of these materials, animal-derived collagen is the most widely used barrier material, as parative study, Friedman et al showed a clear advantage to perithe characteristics that make it favorable to surgeons include: good implant defect resolution with a ribose cross-linked membrane handling properties, ie, it is pliable, adapts and adheres well to bone, compared to a commercially available, noncross-linked barrier.9 and can be sutured; a relatively high safety profile in that there is a This was also demonstrated by Cook and Mealey in an extrac lack of an inflammatory reaction related to breakdown by-products; tion socket model when a bone replacement graft material was and rapid collagen breakdown by the host, which decreases the risk covered by a ribose cross-linked membrane without primary closure in humans.10 of infection and eliminates the need to retrieve the material.4 A unique finding with a ribose cross-linked collagen membrane Regarding barrier function, noncross-linked collagen degrades rapidly and requires replacement in several weeks.5By cross-link is the in situ ossification of the material upon re-entry. Not only is significant bone regenerated without inflammatory reactions, but ing collagen fibrils, the time it takes for a collagen membrane to
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Volume 39, Number 1
Fig 1. Case 1, in itial p re s e n ta tio n o f f o jr - u n it FPD. Fig 2. F a ilin g mes a a b u tm e n t at to o th No. 6. Fig 3. L a rg e auccal dehiscence :y p e d e fe c t a p p a ren t a fte r im p la n t place m ent. Fig < M ineielized t o r e a llo g ra ft used to o b tu ra te d e fe ct. Fig 5. Sugar cross-linked c o l agen n e m b ra n e placed ove r th e de fect. Fig 6. B uccal and patetal flgos sutu re d. Rg 7. A t 1C -weeks nealing, im p la n ts w o u ld be u r.co.e red.
the inner layer of the material appears to serve as a substrate fixossification.11This has been demonstrated in hum ans where along with ossification of the membrane, the density of bo le in contact with the ribose cross-linked collagen barrier suggested that this material enhanced bone regeneradon with a stimulatory effect on neighboring osteoblasts and undi~erentdated stem calls.12 This report of two cases demorstrates clinically t re efficac y of a sugar cross-linked collagen membrane in per -imp lent and site development type defects as well a s its ability to ossify and achieve bone regeneration.
Case 1 A 60-year-old woman was referred to the periodo m ist :or treatmetit of her maxillary right posterior sex) a n t Toe existing fain-unit fixed www.compendiumlive.com
partial denture (FPD) requ.rec replacement due to a falling mesial (tooth No. 6) abutment (Figure 1 anc Figure 2D. After sectioning of the bridge between the loealthy abutment tooth No. 3 anc the ponti: in the No. 4 position, a fril-tloic-cness flap was reflected. The fractured canine was extract ed. preserving the buccal bone at the coronal aspect of the alveolus Implant placement was performed accorilng to the prosthetic t'eatm eiit plan. This resulted in a large buccal dehiscence type defe : t exposing approximately 8 non: to 9 m m of implant surface (Figure 3). The defect was obturated udth a mineralised bone allograft (OraG'aft FDBA, LifeNe: Health lifenediea fi.org) (Figure 4), and asugar cross-linked cell agen membrane (Ossix Flus, Datum Dental Ltd., ossix-dental.conp) (Figure 5) was p aced over the de fect ar.d beneath the periosteum cf rhe buccal and palatal daps. Jam m y 2018
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herringbone appearance of the underlying regenerate, resem bling the texture of the barrier membrane (Figure 9). The hard, nonpenetrable nature of this specific pattern, along with the white, calcified surface of the tissue, suggested that the mem brane may have served as a substrate for ossification, implying the ossification of the inner aspect of the barrier, as dem on strated by Zubery et al.12 After 6 weeks of soft-tissue maturation, the site was restored with a screw-retained, three-unit FPD (Figure 10).
Case 2 A 62-year-old man presented to the periodontist with two symp tomatic abutment teeth. These teeth were supporting a provisional bridge, which was deemed hopeless due to the carious and endodontically involved supporting teeth (Figure 11). After flap re flection and extraction of the teeth, the sockets were thoroughly debrided with ultrasonic and manual instrumentation. Both sites were augmented with the same mineralized bone al lograft (OraGraft FDBA) as used in the first case. Likewise, the same ribose cross-linked collagen membrane as used in the first case (Ossix Plus) was passively adapted over the surgical site and beneath the periosteum of the buccal and palatal flaps (Figure 12). The flaps were reapproximated without achieving 100% primary closure (Figure 13). After about 5 months, the site was reopened for implant place ment. The superficial layer of the membrane was easily removed, revealing a herringbone-textured, hard bony surface similar to that which was seen in the first case (Figure 14). Because the regener ated bone quality facilitated primary stability, a single-stage healing protocol was selected. After about 10 weeks of healing, restorative therapy commenced. The site was restored with a screw-retained, three-unit, implant-supported FPD (Figure 15).
Discussion
Fig 3 C:> agen membrane relatively intact at 10 weeks. Fic 9. A fter removal o f m arrbrare, resolution o f peri-implane defect was evident.
Fig i0. R e sto 'a to n of site with screw-retained, to re e -u rit F 3D f'e s to 'at ve tre a lm e rt p e ';onned by Gregg Rothstein, DM DU
Tne paicual Tap was thinned, and a connective tissue pedicle was rotated to cover the exposed membrane over the mesial implant position and sctm ed to the buccal flap. The buccal and palatal haps wete then approximated and sutured with a monofilament poMetrafluaroethylene (PTFE) suture (Gore-Tex Suture, Gore gc remec.cal.com) (Figure 6). After 10 weeks of healing, the patient returned for surgical unccvery of the tv/c implants and connection of heal.ng abutnfimts ( 'igure 7) Following a full-thickness flap reflection to ccn'irm osseous regeneration, the remaining collagen membrane was tou 'd relatively intact (Figure 8). It was easily- removed, revealing ccmolete resolution of the peri-implant defect and a 46
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The two cases in this report demonstrate not only the efficacy of a ribose cross-linked collagen membrane, but also its potential to serve as a substrate for ossification. The new bone formed un der the grafted space beneath the membrane was of good quality subjectively, allowing for prosthetically guided implant placement, which made it possible for the prostheses to be screw retained. Advantages of this approach include retrievability and avoidance of potential biologic complications related to retained, submu cosal cement. Clearly, regeneration of lost or deficient alveolar bone is critical for successful implant therapy. The advantages of biomaterials that are capable of optimal regeneration without early degradation and soft- or hard-tissue reactions are evident. The early loss of barrier function may compromise regenerative outcomes. This is espe cially crucial when the membrane is not completely submerged with primary flap closure at the time of augmentation. The second case presented in this article clearly demonstrated the prolonged barrier function of the sugar cross-linked membrane even without primary flap coverage. This particular barrier is also capable of ossification, as has been demonstrated. Histologic evaluation has shown the affinity Volume 39, Number 1
for bone form ation in proximity to this m em brane in sinus aug m entations . 1:1 The affinity for osteoblast-like cells for this material has been dem onstrated in vitro . 14 Com pared to noncross-linked collagen, in which the cells are m ore loosely organized in prox im ity to the b arrier m em brane, the sugar cross-linked collagen dem onstrated a m ore dense and organized arrangem ent of bone forming cells in vitro. T he ability of th e sugar cross-linked collagen m em brane to facilitate bone augm entation is an attractive feature to im plant surgeons. In a case series, Scheyer and M cGuire 15 dem onstrated sim ilar findings in large peri-im plant defects, attributin g their success to the extended resorption tim e and biocom patibility of the membrane.
with predictable and significant ossification of the m embrane and defect resolution. DISCLOSURE
Dr. Levin has received lecture and consulting com pensation from D atum Dental Ltd. Dr. Zubery is Chief Medical Officer for Datum Dental Ltd.
ABOUT THE AUTHORS
Barry P. Levin, DMD Clinical Associate Professor, University o f Pennsylvania School o f Dental Medicine, Philadelphia, Pennsylvania; Private Practice limited to Periodontics and Dental Implants, Jenkintown, Pennsylvania
Conclusion T he curren t authors found sim ilar outcom es regarding the use of sugar cross-linked collagen m em branes to those published by Scheyer and M cGuire . 15 The ease of handling, resistance to early degradation when exposed, and predictable osseous regenerative outcomes make this m aterial an attractive choice as a barrier mem brane in im plant practice. This case presentation demonstrates the possibility of membrane ossification. The cases presented are from a private periodontal prac tice, where ungrafted controls were not included for ethical reasons. Though this is not a randomized, double-blind, clinical trial, the authors do report consistent findings in their two specialty clinics,
Yuval Zubery, DMD ChiefMedical Officer and Co-owner, Datum Dental Ltd., Lod, Israel; Private Practice limited to Periodontics and Dental Implants, Ramat Hasharon, Israel
REFERENCES
1. Dahlin C, Andersson I, Linde A. Bone augmentation at fenestrated implants by an osteopromotive membrane technique. A controlled clinical study. Clin Oral Implants Res. 1991;2(4):159-165. 2. Nyman S, Lindhe J, Karring T. Reattachment-new attachment. In: Lindhe, J, ed. Textbook o f Clinical Periodontology. Copenhagen, Den mark: Munksgaard; 1988:409-429. 3. Melcher AH. On the repair of potential of periodontal tissues. J
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CASE REPORT | GUIDED BONE REGENERATION
Fig II. Case 2, initial presentat or shc
