Periodontal bone defects: classification and treatment

Periodontal bone defects: classification and treatment

1. Classification of periodontal bone defects: 
2. Introduction :

The key to the problem of chronic destructive periodontal disease lies in the changes that occur in the bone. Changes in other tissues of the periodontium are important, but ultimately it is the destruction of the bone that is responsible for tooth loss. 

2. Etiopathogenesis:

Bone destruction in periodontal disease is caused mainly by local factors. It can also be caused by systemic factors, but their role has not been defined. Local factors responsible for bone destruction in periodontal disease are divided into two groups: those that cause gingival inflammation, and those that cause occlusal trauma. Whether acting alone or together, inflammation and occlusal trauma are responsible for local bone destruction in periodontal disease, and determine its severity and shape. Bone lysis caused by the extension of gingival inflammation is responsible for the reduction in alveolar bone height, whereas occlusal trauma causes bone lysis lateral to the root surface. 

3. Classification of bone defects and forms of bone destruction in periodontal disease:
   1. Horizontal bone lysis:

 This is the most common form of bone destruction in periodontal disease. The height of the bone is reduced, and the bone margin is almost perpendicular to the tooth surface. The interdental septa and the buccal and lingual tables are affected, but not necessarily to the same degree around the same tooth. 

2. Vertical or Angular Lesions: 

Vertical or angular lesions are those that occur in an oblique direction leaving a cavity in the bone along the root; the base of the lesion is apical to the surrounding bone. In most cases, angular lesions are accompanied by infrabony pockets; infrabony pockets always have an underlying angular lesion. Infrabony pockets are classified according to the number of walls, depth and width of their underlying bony lesion, important characteristics that can influence the choice of a treatment technique. Angular lesions can have one, two or three walls. The number of walls in the apical part of the lesion may be greater than in the occlusal part. In this case, the term combined bony lesion is used. Angular lesions can be shallow and narrow, shallow and wide; deep and narrow, deep and wide; they usually occur in forms that are characteristic of these types. 

Vertical lesions between teeth can usually be seen radiographically, although they are sometimes obscured by thick bony tables. Angular lesions may also occur on the lingual or palatal buccal surfaces, but these lesions are not visible radiographically. Surgical exposure is the only reliable way to determine the presence and configuration of vertical bony lesions. The three-walled vertical lesion has also been called an infrabony lesion. These most commonly occur mesial to the upper and lower second and third molars. The one-walled vertical lesion is also called a hemiseptum. 

3. Bone craters:

Bony craters are concavities located within the crest of the interdental bone bounded by the buccal and lingual walls. Craters have been observed to constitute approximately one-third of all lesions (35.2%) and approximately two-thirds (62%) of all mandibular lesions. They are twice as common in the posterior segments as in the anterior segments. 3.2.4 Bulbous contours of bone. These are bony thickenings caused by exostoses, by functional adaptation, or by buttress formation of the bone. They are observed more frequently in the maxilla than in the mandible. 

4. Uneven edges:

These are angular or U-shaped lesions caused by resorption of the vestibular or lingual alveolar cortex, or by significant differences between the height of the vestibular or lingual edges and the height of the interdental septa. These lesions have also been referred to as inverted architecture. They are more common in the maxilla. 

5. Protrusions: Protrusions are plateau-like bony ledges that are caused by the resorption of thickened bony tables. 
6. Fenestration and dehiscence: 

Fenestration is the term used to describe isolated parts where the root is exposed, and where its surface is covered only by the periosteum and the overlying gum, in the case where the bony edge is intact; if these exposed parts extend to the edge, they are called dehiscences. 

7. Exostosis: 

Exostoses are bone growths of varying size and shape. They occur more often on the vestibular surface than on the lingual surface and do not appear to serve any function. 

8. Bulbous outline of the bone: 

These are bone thickenings caused by exostoses, functional adaptation or buttress formation of the bone.

2. Treatment of bone defects:
3.  Principles of bone surgery:

   Bone defect correction is grouped into:

• Bone resection or resective surgery which includes osteoplasty and osteotomy.
• Additive or reconstructive surgery aimed at increasing the dimensions of the attachment system.

2. The different therapeutic techniques:
   1.  Subtraction technique (resective bone surgery):

   Resective techniques include osteoplasty and osteotomy, which involves remodeling of the alveolar bone with removal or elimination of the supporting bone, unlike osteoplasty which does not require removal of bone and therefore allows harmonization of the contours while sparing bone tissue.

   The amount of bone to be removed can only be decided during surgery after the flap has been elevated and the granulomatous tissue has been removed.

1.  Indications and contraindications of COR: 

   → Indications:

    – COR is reserved for all defects < 3mm, hemi septa, correction of bone exogrowths.

    – Its scope of indication also extends to the establishment of an adequate biological space and requires coronal elongation.

• Tori, exostoses and irregular edges.
• Interradicular lesions.
• Narrow and wide shallow intrabony defects.
• Residual bone defects after attempted regeneration.

   → Contraindications:   

• Maxillary sinus floor very close to the bone defect and proximity to the roots.
• Periodontal pockets larger than 8mm after initial preparation.
• Bottom of the apical bone defect at the level of the root trunk of multirooted teeth.
• Significant tooth mobility.

2. The advantages and disadvantages of COR:

   → The advantages:

• Reliable
• Short term result
• Obtaining a gingivo-osseous morphology promoting effective maintenance. 

   → The disadvantages:

• Causes loss of attachment.
• Root exposure → unreliable aesthetic result.
• Risk of sensitivity.
• High risk of root caries.
• Risk of speech problem.

3.  COR in the treatment of interradicular lesions: 

    ● Objectives:

• Eliminate the open inter-root space and make curettage of the residual root possible.
• Eliminate the periodontal pocket by removing the inter-radicular space.
• Improve the shape of the inter-root space to facilitate cleaning.
• Preserve the maximum amount of periodontal tissue for the residual root.
• Keep multi-articulated teeth. 

    ● Hemisection 

    ● Root amputation:

    ● Tunneling: (see details in the course of treatment of interradicular lesions).

2.  Reconstruction or filling techniques:

Reconstructing a periodontium essentially means restoring a new attachment.

ROSS and COHEN defined the new attachment as the neoformation of the three elements composing the triad namely: cementum, periodontal ligament and alveolar bone, to confirm the existence of a new support system a microscopic confirmation is necessary.

1.  Without contribution:

   Regenerative techniques involve debridement and curettage of lesions.

   PRICHARD demonstrated that certain bone lesions were likely to regenerate without surgical intervention but by simple curettage of the lesion:

   → Open curettage: review the course of flap procedures.

2.  With contribution:

The principle consists of depositing, after curettage of the lesion, a filling material capable of increasing the regeneration potential of periodontal tissues.

The material used must meet several criteria:

• Be biocompatible and do not induce an immune reaction
• Being osteogenic (osteoconductive and/or osteoinductive)
• Be available, sufficient quantity and easy to handle
• Provide massive assistance to the osteogenic process.

      – Be replaced by newly formed bone during the repair process.

Periodontal bone defects: classification and treatment

   → Indications and contraindications for bone grafting:

• Indications:

– Deep intraosseous defect (except interradicular lesion)

– Advanced periodontitis with thin gingiva

– Combined with an RTG for easy handling 

• Contraindication :

– Significant gingival recession at the surgical site

– Insufficient height of keratinized gingiva

– Advanced inter-radicular lesion

   → The materials of the grafts used: 

    ● Autografts: the graft is taken from the same individual

    ● Homografts: the graft is from another individual of the same species 

It is necessary to differentiate:

Isograft	Allograft
The donor is genetically identical to the recipient → identical twin	Donor and recipient of the same species but genetically differentSource: intra or extra oral, corpse or living being

   → Periodontal repair using RTG:

    ● Biological principles of RTG: 

      RTG has been described as a regenerative method of periodontal tissues, it is currently the most effective method of periodontal tissue regeneration.

      The principle of RTG is to prevent apical migration of the epithelium by placing a barrier between the flap and the dental root.

      It can be used on intraosseous defects and interradicular lesions .

    ● Choice of membrane:

• Non-resorbable membrane:

– Polytetrafluoroethylene (PTFE-e) materials for regeneration (GORE –TEX)

– Titanium reinforced polytetrafluoroethylene, titanium reinforced PTFE membrane.

• Resorbable membrane:

– Collagen: tissue guide, paroguide

– Synthetic polymer: GC membrane, resolvete, vicryl

   → Association of membrane and bone graft:

   Some authors have proposed a combined technique by combining the membrane with a bone graft.

        – This association aims to prevent the collapse of the membrane in the lesion.

        – New bone formation can be improved 

   → Growth and differentiation factors:

Growth factors	Results
Platelet-driven growth factor (PDGF)	Stimulates cell division: osteoblasts and periodontal ligament cells
Insulin-derived growth factor (IGF)	Mitogenic effectStimulates the proliferation of pre-osteoblastsSynthesis of type I collagen

Bone morphogenetic proteins: good morphogenetic protein, BMP

• Derived from bovine or human bone, they are:

– Mitogen

– Change of mesochymal cells into osteoblasts thus inducing bone formation

• Enamel matrix proteins: Endogain

– Porcine enamel matrix protein

– After total debridement of the root surfaces, these proteins cause an improvement in attachment gains (2.2 mm) and bone filling which would increase over time.

– They can be associated with membranes.

Periodontal bone defects: classification and treatment

  c- Guided bone regeneration (GBR):

• ROG is particularly useful in implantology when dehiscences and fenestrations are present at the sites.
• ROG provides the height of lost alveolar bone, as improvement in alveolar crest morphology is possible with ROG.

Periodontal bone defects: classification and treatment

ROG	RTG
– The wound is completely closed by the flaps- The adaptation of the membrane is easy- The results are very predictable	– The wound remains open- The adaptation of the membrane is difficult- The results are unpredictable

    → The conditions for success of the ROG:

  Success depends on factors such as:

  – The desired regeneration volume; if this volume is large, it will cause technical difficulties linked to the risks of membrane collapse.

  – The real possibility that bone cells will have to populate the space provided by the membrane without being inhibited by other cell types, in particular cells from the mucosal connective tissue.

  – The type of bone defect; authors agree that vertical augmentation of a bone crest is difficult or even sometimes impossible to obtain…

3.   Conclusion : 

Resectoscope or regenerator, the therapeutic rationale must focus on stabilizing bone destruction and preserving the dental organ as much as possible.

In any case, maintenance of the treated sites is essential for the long-term validity of our surgical treatments.

Periodontal bone defects: classification and treatment

  Sensitive teeth react to hot, cold or sweet.
Sensitive teeth react to hot, cold or sweet.
Ceramic crowns perfectly imitate the appearance of natural teeth.
Regular dental care reduces the risk of serious problems.
Impacted teeth can cause pain and require intervention.
Antiseptic mouthwashes help reduce plaque.
Fractured teeth can be repaired with modern techniques.
A balanced diet promotes healthy teeth and gums.
 

Periodontal bone defects: classification and treatment