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Guided Bone Regeneration

Banner_Guided_Bone_Regeneration

Since the 1980s, dental implantology has become widespread

Back then, residual bone support was the guide for implant positioning, whereas today prosthetic restoration determines the position. Bone regeneration was therefore a requirement. Multiple techniques were created, among them, guided bone regeneration (GBR) took pride of place in the therapeutic arsenal of surgeon-dentists and oral surgeons.

 

The history of GBR

Guided bone regeneration emerged from periodontology and the Guided Tissue Regeneration (GTR) technique. Described by Nyman et al. in 1980 and 1982, the biological procedure for GTR uses a physical barrier enabling cellular recolonisation of radicular surfaces by periodontal cells(1),(2),(3).

This idea was broadened to include bone regeneration by Dahlin et al. in 1988, inspired by the findings of Murray et al. in 1957, who had noted bone regeneration within a plastic cage introduced to a bone defect in the iliac bone of a dog(4), they discovered it was possible to reform bone around implants placed in rabbit tibias and covered with ePTFE (expanded polytetrafluoroethylene) membranes(5).

The first GBR used a rigid membrane for blood clot stabilisation and for ensuring osteogenic cells were able to colonise and regenerate the space, in this way protected from invasion, with junctional epithelium cells which heal more rapidly.

Biomaterials were then added enabling support of the membrane, which was no longer required to be rigid, to leave space for less restrictive resorbable membranes. Next, variants appeared, such as use of osteosynthesis screws to  maintain the membrane at a distance such as “tent poles” or use of cortical bone slices as rigid membranes in formwork techniques.

 

Biological principles

Indications_GBR uses a physical barrier enabling cellular recolonisation

The concept of guided bone regeneration rests on the following principles(6)

  • Maintenance of the space required for bone regeneration, this space will promote angiogenesis and bone formation,
  • Maintenance and protection of the blood clot, source of the bone regeneration,
  • Placement of a barrier to cellular invasion of the junctional tissue and the gingival epithelium, to prevent cellular competition, unfavourable to bone mineralisation, taking place,
  • Gingival sutures to be obtained and maintained with successful management of underlying postoperative forces.

 

Indications

Indications for guided bone regeneration:

  • Presence of peri-implant dehiscence and fenestration,
  • Residual peri-implant intraosseous defects,
  • Care of post extraction socket implantation site,
  • Localised bone crest augmentation,
  • Treatment of bone defects in future implantation sites preventing implant placement or implant placement in an axis favourable both aesthetically and for the functionality of the future prosthesis.

Operative Technique

  • Incision,
  • Flap detachment,
  • Preparation of the recipient site: decortication(7),(8),
  • Palate/lingual positioning of the membrane,
  • Addition of biomaterial,
  • Repositioning of membrane and fixation (pins, sutures, etc.),
  • Hermetic flap closure without tension.

Materials

Indications_BoneGuard®, resorbable membrane for use in GBR

The membrane is the cornerstone of GBR, often combined with filling material.

 

Membranes

These are of two types: resorbable and non-resorbable.

 

Non-resorbable membrane:

  • Advantages: Significant mechanical properties (no requirement to use filling material for a small defect), Eased manipulation without risk of tearing or deterioration.
  • Disadvantages: Placement of material required, High risk of complications in the event of exposure.

 

Resorbable membrane:

  • Advantages: No removal, Simplified surgical procedure, Fewer postoperative complications.
  • Disadvantages: No control of the barrier function, Possibility of interference between resorption and healing, Requirement for use of biomaterial to support the membrane.

 

Biomaterials

Many biomaterials are associated with guided bone regeneration, here is a brief summary.

 

Autograft: Bone graft from recipient

  • Advantages: Osteogenic graft, No risk of infection or rejection.
  • Disadvantages: Second operative site required, Longer procedure, Worse postoperative period for the patient, Limited quantities of grafts.

 

Allograft: Bone graft from member of same species as recipient

  • Advantages: No second operative site, Reduced procedure time, Unlimited quantities of grafts, Good quality osteoconductive properties.
  • Disadvantages: No osteogenic properties, Different regulatory framework of medical devices .

 

Xenograft: Bone graft from member of different species to recipient

  • Advantages: No second operative site, Reduced procedure time, Unlimited quantities of grafts, Medical device.
  • Disadvantages: No osteogenic properties, Poor graft remodelling.

 

Synthetic graft: Synthetic bone graft produced in the laboratory

  • Advantages: No second operative site, Reduced procedure time, Unlimited quantities of grafts, Medical device, Low cost.
  • Disadvantages: No osteogenic properties, Poorly predictable results.

 

 

Key factors for success

Whatever membrane and biomaterial is used, success mainly depends on the following three points:

  • Good preparation and bleeding of the recipient site,
  • Total immobility of the area (membrane fixation),
  • Patency of sutures.
(1) Nyman S, Karring T, Lindhe J, Planten S. Healing following implantation of periodontitis affected roots into gingival connective tissue. J Clin Periodontol 1980 7: 394401
(2) Nyman S, Gottlow J, Karring T, Lindhe J. The regenerative potential of the periodontal ligament. An experimental study in the monkey. J Clin Periodontol 1982a 9: 257-265
(3) Nyman S, Lindhe J, Karring T, Ryander H. New attachment following surgical treatment of human periodontal disease. J Clin Periodontol. 1982b 9: 290-296
(4) Murray G, Holden R, Roachlau W. Experimental and clinical study of new growth of bone in a cavity. Ann J Surg 1957 95: 385-387
(5) Dahlin C., Lindhe A., Sennerby L., LEKHOLM U., Nyman S., Generation of new bone around titanium implants using a membrane technique : an experimental study in rabbits. Int. J. Oral Maxillofac. Implants. 1898 ; 4 : 19-25
(6) Buser et al. Localized ridge augmentation using guided bone regeneration. Surgical procedure in the Maxilla. Int J Periodontics Restorative Dent 1993; 13: 29-45
(7) Lundgren AK, Lundgren D,Hammerle CH, Nyman S, Sennerby L. Influence of decortication of the donor bone on guided bone augmentation. An experimental study in the rabbit skull bone. Clin Oral Implants Res 2000;11:99-106
(8) Nishimura I, Shimizu Y, Ooya K. Effects of cortical bone perforation on experimental guided bone regeneration. Clin Oral Implants Res 2004;15:293-300