Lateral Ridge Augmentation Using Cross-linked or Non-cross-linked Collagen Membrane
Condition: Bone Loss
Study type: Interventional

Summary: 
      The objective of the present trial is to test clinically, radiographically and histologically
      , in a lateral alveolar ridge augmentation model (without simultaneous implant placement) the
      efficiency in supporting bone formation of a glutaraldehyde cross-linked collagen membrane
      compared to a non-cross-linked collagen membrane with the use of a composite
      autograft-xenograft mix prepared in a 1:3 ratio
    

Detailed description: 
      This study is a pilot one, no sample size calculation has been performed. Random allocation
      was done by the sequentially sealed envelope method.

      Interventions

      Pre-operative preparation:

        -  Scaling and root planning and delivering proper hygiene instructions.

        -  Fabrication of the occlusal stent/radiographic guide (Silicone impression of the
           concerned arch and pouring of the model. Denture teeth are added on the edentulous space
           of the cast. A 2 mm thickness clear resin sheet is adapted to the cast with a vacuum
           forming machine. The borders of the stent are trimmed with a tungsten carbide bur to
           remove the parts that are covering the soft tissues. At the level of the surgical site,
           the intaglio of the guide is reduced in a way to prevent any interference with the
           swollen soft tissues during the one-week CBCT assessment. In the middle of each denture
           tooth, 2 mm cylindrical holes are created occlusally. Gutta-percha is inserted in these
           holes to serve as radio-opaque markers and as reference points for per-operative
           measurements.

        -  Pre-operative Cone Beam CT (CBCTpreop) with the radiographic guide/occlusal stent in the
           mouth

      Surgical intervention:

      Patients are put on an antibiotic regimen consisting of 1 g co-amoxiclav taken twice daily
      (Augmentin, GlaxoSmithKline, Brentford, United Kingdom), starting the evening prior to
      surgery and continued for 10 days. For patients allergic to penicillins, Clindamycin 300 mg
      taken every 6 hours (Dalacin C, Pfeizer, New York City, NY, USA) is prescribed. Before
      surgery, the patient is asked to rinse with 0.12% chlorhexidine solution for one minute.
      Local anesthesia is delivered using 4% articaine with epinephrine 1:100,000 (Septanest,
      Septodont, Saint Maur des Fosses, France). After mid-crestal and vertical releasing incisions
      are being made, full thickness flaps are raised. The recipient bone is curetted to remove any
      soft tissue that may impede bone healing. Using a ridge mapping caliper, Crestal Bone Width
      is recorded at 1 (CBWpreop1), 3 (CBWpreop3) and 5 (CBWpreop5) mm from the crest at the level
      of the gutta-percha markers of the guide. Using a periodontal probe, another measure is
      recorded from the Ridge Crest to the Border of the Guide (RC-BG). This measure will be used
      at the 6-month re-entry to locate the vertical position of the pre-operative ridge mapping
      measurements in case of vertical bone changes. On the buccal flaps, superficial periosteal
      releasing incisions are performed to release the flap tension and to access the submucosal
      tissues. Once accessed, the submucosal tissues are stretched by inserting the wide end of a
      periosteal elevator into the incision line and pushing it in a coronal direction, resulting
      in flap elongation. In the posterior mandible, the lingual flap is elongated by a lateral
      stretching movement using the wide end of the periosteal elevator to separate the sub-mucosal
      tissues from the underlying muscle. More anteriorly in the mandible, a superficial periosteal
      incision is performed in the lingual flap. The buccal aspect of the crest is decorticated to
      ensure vascularization at the recipient site. The particulate bone graft consisting of a
      composite autograft-xenograft is then prepared in a 1:3 ratio mixed in sterile saline. A 0.5
      cc spoon is used to have an exact 1:3 ratio. The spoon is slightly overfilled, and the excess
      is eliminated with a spatula. Only the full spoon content is used in the bone graft mix. The
      autograft is obtained by scraping the adjacent bony region with a bone scraper (SafeScraper
      TWIST, META, Reggio Emilia, Italy). The xenograft used is an anorganic bovine bone mineral
      with a 250-1000 microns particle size (OCS-B Xenomatrix®, Nibec, Chungcheongbuk-do, Korea,
      available also under the name of Straumann Xenograft® and Creos Xenogain®). After opening the
      sequentially sealed envelope, the patient is allocated to test or control groups. In the test
      group a glutaraldehyde cross-linked bovine collagen membrane GCLM is used (RTM Collagen®,
      Osteogenics Biomedical, Lubbock, TX, USA), in the control group a non-cross-linked porcine
      skin collagen membrane is used (Bioguide, Geistlisch Pharma AG, Wolhusen, Switzerland). The
      membrane is fixed first on the buccal side with titanium pins (Masetrpin®, Meisinger, Neuss,
      Germany) in a way to create a pouch like space. Second, the composite graft is applied
      between the membrane and the crest with a slight over fill. Then the membrane is slightly
      stretched, wrapped over the ridge and tightly stabilized palatally/lingually with titanium
      pins. The graft-membrane complex should be completely immobile at finger pressure. A tight
      wound closure is achieved by placing a first line of horizontal mattress sutures followed by
      a second line of interrupted sutures along the horizontal incision. The vertical releasing
      incisions are closed with a combination of Laurel-Gottlow sutures and interrupted sutures.
      The sutures used are 4(0) PTFE monofilament sutures (Osteogenics Biomedical, Lubbock, TX,
      USA). Beside the antibiotic regimen described earlier, all patients are prescribed 0.12%
      chlorhexidine mouthwash (twice daily for 2 weeks, starting from the day after surgery),
      NSAIDs drugs (Bruffen 400mg every 6 hours, Abbott Laboratories, Illinois, CHI, USA) and/or
      paracetamol-opioid analgesics (Solpadeine, Omega Pharma Nazareth, Belgium). An extraoral cold
      pressure dressing is applied to minimize postoperative swelling. Sutures are removed 3 weeks
      after surgery.

      During the first week after surgery, a Cone Beam CT (CBCTpostop) of the operated region is
      performed, with the radiographic guide in place.

      Follow-up visits will be performed after 1, 3, 6, 10, 14, 18, 22 and 26 weeks.

      Re-entry:

      At 6 months post-surgery, another Cone Beam CT (CBCTre), with the same radiographic guide in
      place, is taken for bone volume assessment and for implant planning. Mid-crestal and vertical
      releasing incisions are made. Full thickness flaps are raised, and the pins are removed. Any
      non-integrated bone graft material is gently scraped and washed out with saline. The guide is
      put in place and using the previously recorded RC-BG measurement to correctly locate the
      level of the ridge crest before the ridge augmentation surgery, Crestal Bone Width is
      recorded with the ridge mapping caliper at the same locations (CBWre1, CBWre3, CBWre5) taken
      during the regeneration surgery. In addition, a UNC-15 periodontal probe is pushed with
      pressure against the ridge at a 45 degrees angle at the level of each gutta-percha marker and
      at 3 mm form the ridge top. The amount probe penetration in the grafted bone volume is
      recorded.

      A 2 mm diameter trephine bone biopsy is collected for histomorphometrical and
      immunohistochemichal analysis. When possible, the biopsy is extracted horizontally from the
      buccal aspect of the ridge at 4 mm from the crest, otherwise it will be collected vertically
      from the ridge top. One biopsy is collected per patient, taken where the lateral ridge defect
      is the most severe.

      Then the implants are inserted, at the prosthetically planned positions, according to the
      manufacturer's instructions. Flaps are sutured and a post-operative medication is prescribed
      consisting of an antibiotic coverage, an analgesic, and a chlorhexidine mouthwash.

      Three months later, the implants are uncovered for abutment connection and will be
      subsequently restored.
    

Intervention name(s): non-cross-linked porcine skin collagen membrane; glutaraldehyde cross-linked bovine collagen membrane
Intervention type(s): Other; Other
Intervention description(s): non-cross-linked porcine skin collagen membrane used is Bioguide, Geistlisch Pharma AG, Wolhusen, Switzerland.; glutaraldehyde cross-linked bovine collagen membrane GCLM used is RTM Collagen®, Osteogenics Biomedical, Lubbock, TX, USA.
Other intervention name(s): Bioguide; Cytoplast RTM
Intervention MeSH terms: Glutaral
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: This study is a pilot randomized clinical trial with parallel groups, with an observation period of 6 - 9 months. It is set to identify the equivalence between the test and the control procedures. An equal randomization is set for the 2 groups
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Guided bone regeneration; collagen membrane; crosslinked collagen membrane; Bone augmentation