PERIODONTAL BONE DEFECTS Classification, diagnosis
- INTRODUCTION
The form of bone destruction caused by periodontal disease is determined by various factors. The normal physiological structure, called positive, is then replaced by a so-called negative structure, called defect.
The shape, topography and number of remaining bone walls are important elements to analyze because they will determine the therapeutic approach and the prognosis.
- DEFINITION
Intraosseous lesions correspond to a loss of the anchoring system and the alveolar bone in the interdental, vestibular, lingual or palatal areas: the bottom of the pocket is located apically in relation to the marginal edge of the alveolar crest.
An intraosseous lesion is also called: Alveolysis or vertical lesion, as opposed to horizontal bone loss; or angular lesion, due to the angle formed by the residual bone wall and the root surface; or infraosseous lesion.
- Classifications of intraosseous defects
The classifications of intraosseous lesions make it possible to distinguish several types of lesions according to their healing potential.
The classification of intraosseous lesions IOL is based on the number of bone walls preserved by the pathogenic process of periodontal disease. An IOL can thus have one, two or three residual walls. It is accepted that the more the number of residual bone walls decreases, the more the bone defect is circumscribed by avascular connective and root walls, and the more the potential for bone healing is reduced.
- Classification of Goldman and Cohen 1958
A three-walled lesion involves a single tooth and forms when only one bony wall is destroyed. This type of lesion has favorable healing potential since there is only one root wall in situ exposed to the periodontal pocket that is invaded by subgingival biofilms.
A two-walled lesion involves one or two teeth. A single tooth is involved if the two bony walls are contiguous with loss of one of the two cortices; two teeth are affected by bone loss if the IOL forms a crater that forms after destruction of the interdental bone with preservation of both cortices, the buccal cortex and the lingual or palatal cortex. The healing potential differs depending on the arrangement of the walls.
A lesion in a paro i frequently involves a single tooth. In this type of lesion, only an interdental bony wall is preserved; the vestibular and lingual or palatine cortices are destroyed.
A lesion is said to be complex if it has a different number of coronal and apical walls, generally one or two coronal walls and three apical walls.
PERIODONTAL BONE DEFECTS Classification, diagnosis
Intraosseous lesions (horizontal section): A) 3-wall intraosseous lesion, B) 2-wall intraosseous lesion, C) 1-wall intraosseous lesion, D) complex lesion.
- Classification of Papapanou and Tonetti 2000
Within the infraosseous lesion, we distinguish:
- Intraosseous lesion represents a root component and at least one wall
bone.
- Craters describe a very marked depression or concavity within the
interdental ridges. They are bordered by two vestibular and lingual walls.
Intrabony defects are also classified according to depth and width;
- Shallow and wide lesions
- Shallow and narrow lesions
- Deep and wide lesion
- Deep and narrow lesions.
VI. Forms of bone destruction in periodontal disease
4.1. Horizontal lysis
This is the most common form of destruction in periodontal disease. The height of the bone
is reduced, and its edge becomes horizontal or slightly angled. The interdental septa
and the vestibular and lingual tables are affected, but not necessarily to an identical degree around the same tooth.
4.2. Bone defects
4.2.1. Lesions of the interdental bone
- Bone craters
These are concavities located inside the interdental ridge. They are bordered by two
vestibular and lingual walls.
In 1964, Ochsenbein and Bohannan classified bone craters into 4 categories:
Class 1 : concave crater of 2 to 3 mm with thick vestibular and lingual walls.
Class 2 : concave crater of 4 to 5 mm with thinner walls.
Class 3 : concave crater of 6 to 7 mm.
Class 4 : Crater of variable depth with thin bony walls.
- The hemi-septa
It is the portion of the interdental septum that remains after the mesial or distal part has been
destroyed by periodontal disease.
4.2.2. Marginal bone lesions
- The uneven edges
These are angular or U-shaped lesions that are caused by the resorption of the
vestibular or lingual alveolar cortex.
- Exostoses
These are bone growths of varying shape and volume. They most often occur
on both the vestibular and lingual sides.
- The bulbous contours
It is a thickening caused by exostosis or functional adaptation or buttress
bony.
- The projections
These are plateau-like bony ledges caused by the resorption of thickened bony tables.
- The windows
These are isolated areas where the root is exposed and its surface is covered only by the
periosteum and the overlying gingiva. In this case, the bony margin is intact.
- Dehiscences
It differs from fenestrations by the absence of a bony marginal rim. These are areas without
V-shaped bone tissue, more or less wide and irregular, extending up to half or
a third of the root.
PERIODONTAL BONE DEFECTS Classification, diagnosis
PERIODONTAL BONE DEFECTS Classification, diagnosis
V. Diagnosis of bone defects
The diagnosis of bone defects and their morphology is a key step, which is based on an examination
careful clinical examination and additional examinations.
5.1. Clinical diagnosis
The clinical demonstration of a bone defect is based essentially on probing
Periodontal. The vertical insertion of the graduated periodontal probe allows the determination of the
depth of the lesion. The width of the defect is defined by inserting the probe horizontally
in the vestibulo-lingual direction. This allows to determine if the cortices are present or
destroyed. Thus the survey determines the depth and width of the defect, but cannot
no case define the exact limits of the bone lesion. The additional examination is therefore
essential for diagnosis.
5.2. Radiological evaluation
In the case of infra-osseous lesions, radiological examination allows the area to be analyzed
interproximal as well as root morphology. The retro-alveolar image, taken with
an angulator to ensure strict parallelism of the X-ray film in relation to the large
axis of the tooth, is preferable to the orthopantomogram, considered to be significantly less
accurate due to the numerous geometric deformations generated by this type of examination.
Thus, in 1997, Pepelassi et al. already showed that the clinician had four times more chance
to detect IOLs from a reading of retro-alveolar images than from a reading
of an orthopantomogram.
Caution must be exercised when interpreting a photograph because the superposition of dental structures
and bone which results from the transposition of three-dimensional elements on an image
two-dimensional does not allow the lesion to be observed from all angles.
In the context of intraosseous lesions, the indication for a Cone Beam must therefore be reserved
to difficult clinical situations requiring a differential diagnosis.
PERIODONTAL BONE DEFECTS Classification, diagnosis
CONCLUSION
Destructive periodontal disease causes changes in the alveolar bone
which is responsible for tooth loss. The diagnosis of bone defects is based on a
careful clinical evaluation and good radiological interpretation. This allows
clearly identify its defects and thus promote the establishment of a therapeutic approach
correct.
PERIODONTAL BONE DEFECTS Classification, diagnosis
Untreated cavities can damage the pulp.
Orthodontics aligns teeth and jaws.
Implants replace missing teeth permanently.
Dental floss removes debris between teeth.
A visit to the dentist every 6 months is recommended.
Fixed bridges replace one or more missing teeth.