Periodontal bone defects: therapeutic modalities

Periodontal bone defects: therapeutic modalities

Periodontal disease can cause various bone defects of different shapes and morphologies. After non-surgical treatment and reassessment, correction of these defects can be considered by bone surgery, which can be resective or regenerative.

2. Definition of bone surgery:

The term bone surgery refers to surgical procedures performed on bone with the aim of remodeling or restoring it. It aims to correct bone lesions caused by periodontal disease or anatomical deformity, or both. These bone lesions can be treated using different techniques depending on the authors and the various situations. The most commonly used are:

• Subtractive or resective bone surgery: that is to say, flattening the lesion.
• Additive or regenerative bone surgery: attempt to fill the lesion with an addition (graft or implant).

3. Resective bone surgery:
   1.  Definition :

Resective bone surgery is a modification of the periodontal alveolar support by subtraction. It includes two techniques: osteoplasty and osteectomy.

Osteoplasty : is a bone remodeling which consists of giving the alveolar process a more physiological shape without resecting the supporting bone.

Osteectomy : is a bone resection which consists of eliminating and/or reducing intra-bony defects by resecting part of the supporting bone.

2.  Goals :

• Reduction or elimination of bone defects. It consists of transforming a shallow intraosseous lesion into horizontal alveolysis.
• Reduction or elimination of periodontal pockets
• Return to physiological bone morphology
• Return to physiological gingival anatomy

3.  indications:

The indications for osteoplasty and osteotomy are different, although the regularization of bone volume and contours comes from the combination of the two techniques.

• Osteoplasty
  • Horizontal alveolysis
  • Shallow (1-2 mm) vestibular or lingual intraosseous lesion resulting from periodontitis.
  • Regularization of interdental craters, circumferential lesions and deep intraosseous defects (>4mm) in preparation for a regeneration protocol.
  • Improvement of the coaptation of the edges of an access or apicalized flap in the case of thick bony edges preventing good repositioning and adaptation of soft tissues.
  • Reduction of anatomical bone abnormalities such as tori or exostoses.
• Osteoectomy:
  • Medium-depth (3-4mm) vestibular or lingual intraosseous lesion resulting from periodontitis.
  • Elimination of periodontal pockets in combination with an apicalized and/or palatal thinned flap.
  • Elimination of anatomical bone anomalies such as tori or exostoses.

4.  Contraindications:

• Osteoplasty:

• Thin interproximal bone.
• Aesthetic sector
• Major phonetic risk.
• Osteoectomy:

• Identical to those of osteoplasty
• Horizontal alveolysis
• Unfavorable crown-root ratio
• Very deep bone defects whose elimination leads to significant bone loss.

5.  Operating protocol:
   1.  technical platforms:

The technical platform is traditionally that of access flaps, to which is added specific instrumentation. There are rotary and manual instruments.

The advantage of rotary instruments is their speed of action, while manual instruments are more precise and allow the recovery of bone chips.

• Rotary instruments:

Rotary instruments usually consist of steel or diamond ball burrs of different diameters which are used on contra-angle or low-speed surgical handpieces (most often steel) or on high-speed turbines (most often diamond).

Only two operating rules must be strictly observed:

1. Constant cooling of the bone surface by irrigation of the rotating instrument.
2. Skillful manipulation sparing the root surface.

• Manual instruments:

There are many hand instruments, such as bone scissors, files, and bone rasps, available for bone resection. They come in a variety of sizes and shapes.

2.  surgical technique:
   • Anesthesia
   • Lifting of a plain thickness flap
   • Degranulation
   • Wound revision and hemostasis to clearly visualize the bone defect.
   • Bone phase: occurs in three stages:
     1. Harmonization of the alveolar support: a gentle sloping plasty of the bone balconies and the elimination of surface irregularities resulting from resorption are carried out.
     2. Modeling of interdental spaces: by creating bone gutters aimed at reproducing the initial physiological anatomy of the interdental concavity.
     3. Bone scalloping: performed by minimally curving the vestibular cortical edge so that the interdental bone is located coronal to the marginal vestibular or lingual bone.
   • Sutures
   • Post-operative advice.

4. Regenerative bone surgery:

The quality of healing of the deep periodontium depends directly on the cell types that colonize the surgical site, particularly the root surface. Regenerative surgeries have been designed to optimize the migration of osteoprogenitor cells and

mesenchymal cells of the medullary spaces and the periodontal ligament within bone lesions. They are therefore indicated in the treatment of large and deep intraosseous lesions (IOLs) that partially respond to non-surgical treatment and flaps

access.

1.  IOL filling:

Can be achieved through autograft or bone substitutes from different organs: allograft (human bone bank), xenograft (animal bone), and alloplastic materials (synthetic materials).

This therapeutic option is particularly indicated for large and deep, self-supporting intraosseous defects with three or two facing walls (crater), i.e. providing a stable receptacle for the implanted product which can be placed in intimate contact with the residual bone walls.

2.  guided tissue regeneration (GTR):

It is a technique that consists of the use of a resorbable or non-resorbable regeneration membrane, isolating a space conducive to healing, corresponding to the principle of exclusion of epithelial cells. Its objective is the formation of new bone, new cementum, a new ligament and new gum.

3.  induced tissue regeneration (ITR):

Induced tissue regeneration is an attachment gain technique using enamel matrix derivatives. It allows the formation of a new functional attachment between

newly formed cementum and regenerated bone.

Enamel matrix derivatives are enamel proteins extracted from porcine wisdom tooth buds. The principle of use is based on the potential of enamel proteins, synthesized and secreted by the epithelial cells of the Hertwig sheath during dental root formation, to induce the differentiation of dental follicle cells into cementoblasts. Amelogenin is the only protein used in periodontology.

When the gel is applied to the surface of a surfaced root free of cementum, the gel precipitates forming a stable hydrophobic extracellular matrix. This matrix interacts with mesenchymal cells of adjacent healthy tissues, promoting their attraction and leading to their proliferation. The gel is believed to restart the developmental program of odontogenesis. The mesenchymal cells differentiate into cementoblasts. The cementoblasts secrete neocementum. This neocementum subsequently leads to the regeneration of the periodontal ligament. Alveolar bone is regenerated upon contact with the neocementum.

4.  Combined techniques:

The three techniques mentioned above can be combined. Thus, the filling can be associated with RTG biomaterials (membranes). As it can be associated with the materials of

RTI, the aim being to combine the biological effects of enamel matrix derivatives with other therapeutic adjuvants in order to potentiate their biological properties and compensate for the lack of physical quality of the gel which cannot serve as a support for soft tissue.

5. Combined technique: resective and regenerative:

Partial osteoestomy is sometimes combined with bone regeneration when the defect is suitable for the latter. This approach is most often adopted in cases of very deep intraosseous lesions where therapeutic compromise may be necessary.

6. Conclusion :

Treatment of periodontal bone defects can be done using two approaches: a reductive or regenerative approach. The choice of technique depends on the shape and morphology of the bone defect.

7. Bibliographic references:

1. Bouchard Philippe, Periodontology and Implant Dentistry, Vol. 2, Lavoisier Edition, 2016.
2. Dridi Sophie Myriam et al., Intraosseous and interradicular lesions, id space, 2017.

Periodontal bone defects: therapeutic modalities

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Periodontal bone defects: therapeutic modalities