PERIODONTAL BONE DEFECTS: THERAPEUTIC MODALITIES
- INTRODUCTION :
Loss of bone anchorage is often considered an anatomical sequela of periodontal disease, because the key to the problem of periodontal disease lies in the transformations that occur at the bone level; transformations at the level of other tissues are also important, but when the final analysis is made, it is the destruction of the alveolar bone that is responsible for tooth loss.
The persistence of bone defects constitutes a favorable ground for the development of periodontal disease, which is why it is imperative to eliminate them to guarantee the survival of the dental organ and this by bone surgery.
- ASSESSMENT OF BONE LESIONS:
There is a very large variation in the morphology and contours of alveolar bone induced by periodontal disease; the bone characteristics that modify the shape of bone destruction in periodontal disease are: the thickness, width and crestal angulation of the interdental septa; the thickness of the buccal and lingual alveolar cortices, the presence of fenestrations and dehiscences on the root surfaces, the thickening of the alveolar bone edges and furcation involvement.
The topography of the bone lesions is determined clinically by probing in 6 regions: 3 vestibular and 3 lingual with a graduated periodontal probe, the interradicular lesions are explored with a curved Nabers probe.
X-rays can be used to determine the type of lysis, the degree of damage, the shape and number of roots.
- CLASSIFICATION OF BONE LESIONS:
Goldman, Cohen, Prichard and many authors have proposed classifications of periodontal bone defects. These classifications are generally based on specific morphological and anatomical criteria and are intended to guide clinicians in making the diagnosis , establishing the treatment plan and predicting the prognosis.
PERIODONTAL BONE DEFECTS: THERAPEUTIC MODALITIES
- Forms of bone destruction in periodontal disease:
a-1: interdental bone
- suprabony defect: decrease in the height of the alveolar bone, bony edge almost perpendicular to the dental surface.
- Intraosseous defect: the lesion occurs in an oblique direction leaving a cavity in the bone along the root, the base of the lesion is apical to the surrounding bone.
Depending on the number of walls affected: the lesion is said to be
1 wall: delimited by a bony wall
2 walls: 2 dental walls and 2 bony walls
3 walls: delimited by 1 dental wall and 3 bony walls
Combined bone lesion: the defect surrounds the tooth partially or completely
a-2: interradicular bone: this is a loss of substance located between the roots of multirooted teeth (several classifications have been proposed by different authors)
- Other forms of bone defect:
b-1: bulbous contours of the bone : these are bone thickenings caused by exostoses, functional adaptation or buttress formation of the bone.
b-2: hemisepta: this is the portion of the interdental septum that remains after the mesial or distal part has been destroyed by disease.
b-3: irregular margins: these are angular or u-shaped lesions that are caused by resorption of the vestibular or lingual alveolar cortex, or by abrupt differences in height between the vestibular or lingual marginal margins and the height of the interdental septa.
b-4: dehiscences: these are u-shaped defects on the vestibular or lingual surface
b-5: fenestrations: represent circumscribed defects on the vestibular or lingual surface
b-5: protrusions: these are plateau-like bony edges which are caused by the resorption of the thick bony tables.
- DEFINITION OF BONE SURGERY:
It is the set of procedures performed on the bone, with the aim of remodeling or restoring it. It aims to correct bone lesions by several methods.
According to KORNFELD (1935), CARRANZA (1956): bone surgery seeks an ideal bone architecture, resulting in a physiological anatomy of bone and gingival tissues, a drastic reduction in the depth of pockets, better control of personal oral hygiene.
According to the Academy of Periodontology (1992): bone surgery aims to correct defects in the bone supporting the teeth and distinguishes osteoplasty or remodeling of the alveolar processes in order to obtain a contour of the physiological bone tissue without reducing the level of attachment, from osteotomy which leads to the reduction of a portion of the bone tissue.
- PRINCIPLES OF BONE SURGERY:
Bone defect correction is grouped into:
1- bone resection or resective (subtractive, excisional) surgery: which includes osteoplasty and osteotomy.
2- additive or reconstructive surgery: aimed at increasing the dimension of the attachment system using various techniques.
- RESECTIVE BONE SURGERY :
Includes 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 the bone and therefore allows harmonization of the contours while sparing bone tissue.
1-a: Indications :
- Surgical release of impacted teeth
- All defects less than 3 mm, hemisepta, outgrowth
- Coronal elongation for the establishment of a biological space
- Interradicular lesions (tunneling, root amputation, hemisection)
- Narrow and wide shallow intraosseous defects (abandoned technique)
- REGENERATIVE OR RECONSTRUCTIVE BONE SURGERY:
- Without contribution:
Regenerative techniques involve debridement and curettage of the lesion, which consists of removing subgingival deposits located on the roots, eliminating granulation tissue and performing root planing. Prichard demonstrated that certain bone lesions were likely to regenerate without surgical intervention but by simple curettage of the lesion.
PERIODONTAL BONE DEFECTS: THERAPEUTIC MODALITIES
a- 1: Indications:
Open curettage or periodontal sanitation flaps are indicated for supraosseous but also infraosseous lesions.
This treatment is used for:
- Access the roots to perform debridement on deep pockets greater than 5mm.
- Planned bone regeneration in an area with an intrabony defect
- Access the furcation
- Re-establish the limits by creating an apically repositioned flap and thus recreate the biological space.
a – 2: Contraindications :
- The sanitation flap, like any periodontal surgery, has absolute and relative contraindications.
- Contraindications relating to the site to be treated:
- Significant mobility
- Severe bone lysis
- Major recession
- Difficulties accessing the site
- Teeth are the prognosis is poor and extraction is inevitable
- Presence of regional infection such as endodontic infection
- Open curettage: As shown by Rosing et al. (1976), careful cleaning of the roots allows for significant reconstruction of the alveolar bone, particularly after open treatment of 2- or 3-walled pockets. But only in the presence of strict oral hygiene. These authors did not observe any reformation of the cementum or the periodontium.
a-3: Technique :
- Full-thickness flap reclination
- Visualization of the lesion
- Curettage and removal of granulation tissue
- Washing and hemostasis
- Flap repositioning and sutures
- With contribution:
The principle of regenerative surgery consists of depositing, after curettage of the lesion, a filling material capable of increasing the regeneration potential of periodontal tissues. The material must meet several criteria:
- Be biocompatible and do not induce an immune reaction
- Being osteogenic: (osteconductive and/or osteinductive)
- Osteoconductive: passive property of a material to receive bone regrowth, by vascular and cellular invasion from the recipient bone tissue in contact with this material.
- Osteoinductive: ability to induce cellular differentiation to synthesize a mineralizable bone matrix
- 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
b-1: Indications : regenerative techniques are indicated in the treatment of intraosseous defects and interradicular lesions.
- They are only intended for angular or circumferential intraosseous lesions equal to or greater than 3 mm.
- Intraosseous lesions with one, two or three walls can be treated with these therapies.
- Interradicular lesions are mainly class II.
b-2: bone grafts:
- Autografts: the grafted material is taken from the same individual
- intraoral site: edentulous ridge, tuberosity, mental symphysis, recent extraction site, ramus, exostosis
- extra oral site: iliac crest spinal cord
- allografts: the graft comes from another individual of the same species:
- freeze-dried bone; origin: cortical bone or medullary bone
- demineralized freeze-dried bone; origin: chemically treated cortical bone or medullary bone
- xenografts: the graft is taken from a different species (usually bovine bone)
- alloplastic grafts: the grafted substance is not bone in nature, they are bone substitutes: tricalcium phosphate, bioglass (perioglass)
b-3: Guided tissue regeneration (GTR) : GTR has been described as a regenerative method of periodontal tissues, it is currently the most effective method of regenerating periodontal tissues with the formation of a new attachment.
The principle of RTG is based on the promotion of regeneration of the attachment system and bone by interposing a membrane between the gingiva and the root to exclude epithelial proliferation from healing [Karring et al.,1993].
PERIODONTAL BONE DEFECTS: THERAPEUTIC MODALITIES
- membrane choice
- 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
b-4: growth factors:
Currently, researchers tend to stimulate the osteogenic potential by adding organic or chemical components to the grafted bone material. These are growth factors that are defined as mitogenic cellular mediators (polypeptides) that influence in various ways the growth (multiplication) and functions of different cells. Used with different vehicles (bone fillers or collagen), these factors are increasingly used to accelerate and improve periodontal healing.
A lot of research is currently focusing on growth factors made up of complex proteins; they could act on the regeneration of periodontal tissues. We will mention osteogenin or the association of “platelet driven growth factor” (PDGF) and “insulin like growth factor” (IGF-1); FGF “fibroblast growth factor”; TGF “transforming growth factor”; EGF “epidermal growth factor”.
- The PRF (Platelet Rich Fibrin) membrane concept:
It is used during additive and regenerative surgeries. The sample is directly centrifuged without the addition of anticoagulant factors or bovine thrombin. In the absence of anticoagulants, platelets are rapidly activated, as well as the different stages of coagulation leading to the formation of a fibrin clot.
Platelet activation thus allows a massive release of growth factors (mainly TGF-B, PDGF, IGF, and EGF) which will be trapped in the fibrin network. PRF is in the form of a matrix that progressively releases cytokines promoting, on the one hand, angiogenesis of the scar site, and on the other hand, the capture, survival and migration of surrounding cells necessary for healing of the site.
b-5: EMDOGAIN enamel protein derivatives:
Porcine amelogenins are a protein fraction of the enamel matrix, capable of forming cementum under the right conditions.
EMDOGAIN triggers a process in human root dentin that is analogous to natural tooth development.[Mimikri,Zehsertrom et al.1997]
b-6: guided bone regeneration:
Guided bone regeneration (GBR) refers to the placement of membranes, the role of which is to isolate the bone site to be reconstructed from surrounding tissues that can inhibit healing.
ROG is sometimes opposed to other reconstruction techniques: autogenous bone grafts, allogeneic, xenografts, synthetic materials. In our practice, it appears that ROG is one of the most predictable techniques for reconstructing edentulous ridges before or during the placement of implants.
Principle: its principle is based on the concept of cellular selection allowing the formation of newly formed bone.
Mechanical isolation of the bone defect using a physical barrier allows new bone formation from the stabilization of a blood clot. Differentiation of stem cells from this initial clot to reconstitute bone volume is then possible.
- CONCLUSION :
Surgical techniques that improve bone morphology can be resective or regenerative. Regenerative treatment depends on several factors: related to the patients but also to the anatomy of the lesion and the choice of treatment methods.
Between resection or regeneration, the therapeutic rationale must focus on stabilizing bone destruction and preserving the dental organ as much as possible.
In all cases, maintenance of the treated sites remains essential to validate our surgical treatments in the long term.
Good oral hygiene is essential to prevent cavities and gum disease.
Regular scaling at the dentist helps remove plaque and maintain a healthy mouth.
Dental implant placement is a long-term solution to replace a missing tooth.
Dental X-rays help diagnose problems that are invisible to the naked eye, such as tooth decay.
The dentist uses local anesthesia to minimize pain during dental treatment.