Guided Tissue Regeneration

DR. ABDULLAH KARAMAT

Regeneration :

is defined as a reproduction or reconstruction of a lost or injured part in such a way that the architecture and function of the lost or injured tissues are completely restored (Glossary of Periodontal Terms 1992)

Guided Tissue Regeneration: The method for the prevention of epithelial migration along the cemental wall of the pocket and maintaining space for clot stabilization is a technique called guided tissue regeneration (GTR). GTR Procedures allowing the repopulation of a periodontal defect by cells capable of forming new connective tissue attachment and alveolar bone.

Melcher 1976 - Following flap surgery, the curetted root surfacemay be repopulated by (1) epithelial cells, (2) gingivalconnective tissue cells, (3) bone cells, or (4) periodontalligament cells.

Nyman(1982) , Gotlow(1984), Karring (1986) did classic studies and proved that only the periodontal cells have the potential for regeneration of the apparatus of the tooth

Clinical application of GTR

Clinical application of guided tissue regeneration (

GTR) in periodontal therapy involves the placement of a physical barrier to ensure that the previous periodontitis affected root surface becomes repopulated with cells from the periodontal ligament.

Treatment of the first human tooth with GTR was reported by Nyman et al. in 1982. Due to extensive

periodontal destruction, the tooth was scheduled for extraction. This offered the possibility of obtaining histological documentation of the result of the treatment. Following elevation of full thickness flaps, scaling of the root surface and removal of all granulation tissue, an11 mm deep periodontal lesion was ascertained. Prior to flap closure, a membrane was adjusted to cover parts of the detached root surfaces, the osseous defect and parts of the surrounding bone.

Histological analysis after 3 months of healing revealed that new cementum with inserting collagen fibers had formed on the previously exposed root surface .

In a later study (Gottlow et al. 1986), 12 cases treated with GTR were evaluated clinically, and in five of these cases histologic documentation was also presented. The results showed that considerable but varying amounts of new connective tissue attachment had formed on the treated teeth.

Barrier membranes:

There are five criteria which are considered to be important in the design of barrier membranes used for GTR ( Greenstein & Caton 1993). These include : biocompatibility , cell occlusiveness , spacemaking , tissue integration and clinical manageablilty

1- Non resorbable

A. e-PTFE

B. d-PTFE

C. Millipore and Nucleopore

D. Silicone barriers

Types of membranes :

2- Resorbable membranes

A. Synthetic

I. Polylactide

II. Polyglycolic acid

III. Vicryl mesh

IV. Cargile membrane

B. Natural : Collagen membrane

Current trends in membranes :

• Membranes containing metronidazole

• Membranes combined with growth factors like PDGF and BMPs

• Combined use with Enamel Derived Proteins (EMDOGAIN)

Indications

1. Class II furcation

2. Infra bony defect.

3. Recession defect (class 1 and 2 )

4. To restore PD attachement in narrow 2 or 3 walled infra bony defect.

5. Alveolar ridge augmentation

6. Repair of apicocetomy defect.

Contra indications:

1. In cases where flap vascularity will be compromised.

2. Very severe defect-minimal remaining periodontium.

3. Horizontal defects.

4. In cases of flap perforation.

Procedure:

Surgery is initiated by sulcular or marginal incisions at both the buccal and lingual aspect of the jaw, followed by buccal and vertical releasing incisions. The releasing incisions must be placed a minimum of one tooth anterior and/or posterior to the tooth that is being treated

Following marginal incisions and vertical releasingincisions on the buccal aspect of the jaw, buccaland lingual full thickness flaps are elevated.

Care should be taken during this procedure to preserve the interdental papillae. All pocket epithelium is excised so that a fresh connective tissue is left on the full thickness flaps following reflection. After elevation of the tissue flaps, all granulation tissue is removed and thorough debridement of the detached root surfaces is carried out using curettes, burs, etc.

Various types of bioabsorbable and non-bioabsorbable barrier materials are available in a variety of configurations designed for specific applications. The configuration most suitable for covering the defect is selected and additional tailoring of the material is performed. The shaping of the material is carried out in such a way that it is adapting closely to the tooth and is completely covering the defect, extending at least 3 mm on the bone beyond the defect margins after placement

The barrier material is placed in such a waythat it completely covers the defect and extends at least 3mm on the bone beyond the defect margin.

For optimal performance, the barrier should be placed with its margin 2-3 mm apically to the flap margin. To maximize coverage of the barrier, a horizontal releasing incision in the periosteum may assist in the coronal displacement of the flap at the suturing of the wound

The elevated tissue flaps are coronally displacedand sutured in such a way that the border ofthe barrier material is at least 2 mm below the flap margin.

Post op :

To reduce the risk of infection and to assure optimal healing, the patient should be instructed to gently brush the area postoperatively with a soft bristle toothbrush and to rinse with chlorhexidine (0.2%) for a period of 4-6 weeks. In addition, systemic antibiotics are frequently administered immediately prior to surgery and during 1-2 weeks after surgery. When a non-bioabsorbable barrier is used, it should be removed after 4-6 weeks. However, if complications develop it may be necessary to remove it earlier.

References

• Jan Lindhe(2008). Textbook of Clinical Periodontology and Implant Dentistry, 4th edition

• Carranza’s Clinic Periodontology 11th edition

• J D Manson & B M Eley – Periodontics, Fourth Edition

• Melcher AH (May 1976). "On the repair potential of periodontal tissues". J. Periodontol. 47 (5): 256–60.

• Nyman S, Lindhe J, Karring T, Rylander H (July 1982). "New attachment following surgical treatment of human periodontal disease". J. Clin. Periodontology

• Gottlow J, Nyman S, Karring T, Lindhe J (September 1984). "New attachment formation as the result of controlled tissue regeneration". J. Clin. Periodontol.

• Gottlow J, Nyman S, Lindhe J, Karring T, Wennström J (July 1986). "New attachment formation in the human periodontium by guided tissue regeneration. Case reports". J. Clin. Periodontol.

“All things are subject to interpretation. Whichever

interpretation prevails at a given time is a function of power and not

truth.”Friedrich Nietzsche