PERIODONTAL DIAGNOSIS IN ORTHODONTICS
Introduction
The prerequisite for any orthodontic treatment is the absence of infection and the presence of a periodontium capable of resisting dental movements. These two elements are essential to carry out the treatment with complete peace of mind, because the consequences of orthodontic treatment, on a diseased or weakened periodontium, are irreversible for the long-term prognosis of the teeth. The periodontium must therefore be the subject of a rigorous, simple and systematic clinical examination (inspection, palpation, probing) and a radiological examination (panoramic, localized retro-alveolar).
2. Diagnosis of an infected periodontium
An infectious periodontium is a periodontium with subgingival reservoirs of bacterial biofilm. Before any orthodontic treatment, the following question must be answered: does this periodontium have infectious reservoirs compromising bone stability?
The answer is not always obvious, because periodontal disease presents very different clinical pictures.
2.1. The screening survey
The pathognomonic sign of periodontal infection is the periodontal pocket. A periodontal pocket is a deepening of the gingivodental sulcus. The gingivodental sulcus is the space between the marginal margin of the gingiva and the coronal part of the epithelial attachment.
This deepening of the gingival-dental groove is measured by the periodontal probe.
It is necessary to dissociate the screening survey from the periodontal charting that periodontologists are particularly fond of.
The screening survey is carried out at the first consultation. It consists of measuring the gingivodental sulcus of each tooth at six sites. It is carried out over the entire mouth if the patient does not have a pocket larger than 3 mm. It ends as soon as several pockets larger than 3 mm are found. Its objective is to answer a fundamental question: does this patient have a periodontal infection?
Any measurements greater than 3 mm, or equal to 3 mm with associated bleeding, reveal pathological bacterial proliferation. This situation requires more or less complex periodontal treatment depending on the pocket depths noted.
The survey values give the level of severity of the periodontal infection and therefore the course of action to take.
Pockets of 3–4 mm with bleeding resolve spontaneously with appropriate dental and interdental hygiene and rigorous scaling
When the pockets exceed 4 mm with or without bleeding, specialized treatment is recommended.
The probing after periodontal sanitation treatment validates the healing. The orthodontist will have to wait for the infection to be eliminated (one month) and then for the healing (two months) before intervening. Depending on the severity of the disease, the period can extend from three to six–eight months.
2.2. Inflammatory signs: inspection
Inflammatory signals are valuable indicators of periodontal infection. Unfortunately, they are inconsistent even in cases of severe infection. Their absence does not indicate a healthy periodontium. Periodontal disease is not always
visible on inspection. This characteristic leads to many diagnostic errors if the survey is not systematic.
2.3. Signs of infection: palpation
Palpation of the periodontium, from the bottom of the vestibule towards the sulcular area, sometimes reveals suppuration. This is a quick test that can diagnose active periodontitis. However, the absence of suppuration on palpation does not indicate a healthy periodontium.
2.4. Radiological signs
Radiological signs, objectifying the level of the alveolar bone, do not reflect periodontal infection but the consequences of periodontal infection, which is the loss of attachment. Radiological bone lysis without periodontal pocket establishes the diagnosis of stabilized periodontitis and does not contraindicate orthodontic activation in any case.
The radiological image is not reliable because it has limitations mainly due to the superposition and deformation of the structures. Periodontal probing allows these limitations to be overcome; it allows the radiograph to be read in three dimensions.
2.5. Special case of orthodontic gingivitis
Orthodontic gingivitis is a purely inflammatory reaction triggered by the presence of orthodontic material and aggravated by bacterial plaque. It is characterized by gingival hyperplasia without migration of the periodontal attachment.
The periodontal probe is 4–5 mm and is associated with floating gingiva whose marginal edge is positioned very coronally (well beyond the enamel-cementum junction). It does not contraindicate the continuation of treatment but requires rigorous hygiene and periodontal maintenance sessions to avoid an infectious complication leading to bone loss. If the diagnosis is correctly made, this gingivitis resolves spontaneously one to two months after the removal of the material. Radiographic examination allows the differential diagnosis to be made.
2.6. Bacterial tests
Their use in screening does not provide any determining element compared to probing. The cost/benefit ratio contraindicates its use in orthodontics.
Probing is an essential part of periodontal diagnosis.
– No pocket larger than 3 mm, no bleeding: orthodontic activation.
– No pocket greater than 4 mm, bleeding: motivation to control dental and interdental plaque, scaling then orthodontic activation at one month
– Pocket greater than 4 mm with or without bleeding: refer to a specialist.
The absence of inflammatory signs is not an indicator of a healthy periodontium.
The presence of inflammatory signs is a valuable warning sign.
The radiological image allows the loss of attachment to be assessed, but does not allow a conclusion to be drawn on the presence or absence of periodontal infection.
3. Diagnosis of a weakened periodontium
A weakened periodontium is a healthy periodontium but presenting bone loss linked to a history of infection, or to an anatomical cause (emergence in the alveolar process) more or less aggravated by a traumatic cause (traction of the frenulum, brushing technique).
Before orthodontic treatment, answer the following question: will this periodontium resist the planned dental movement?
The presence or absence of marginal tissue recession has little influence on the course of action to be taken.
The assessment of the keratinized gingiva is not sufficient. The analysis of the attached gingiva predominates over the previous elements.
Many classifications exist, but are not very applicable clinically and ultimately make diagnosis and management complicated.
The practitioner must know how to detect three risk situations :
(1) Attached gingiva present but too thin.
(2) Absence of attached gingiva.
(3) Bone level below the coronal half.
3.1. Attached gingiva present but too thin
3.1.1. Diagnostic signs
The periodontal probe placed horizontally on the mucosa determines a mucogingival line located less than 3–4 mm from the gingival margin. The periodontal probe determines a sulcular gingival height of 2 to 3 mm.
– Attached gingiva is present for at least 2 mm. The metallic color of the periodontal probe is visible by transparency.
– The attached gum is too thin. This situation is not common.
3.1.2. Conduct to be adopted
If the dental movements are directed vestibularly, it is necessary to reinforce in order to prevent marginal tissue recession. The treatment will aim to thicken the existing gum, to give it back a positive and stable volume over time. The recommended technique will be a buried connective tissue graft technique.
3.2. Absence of attached gingiva
3.2.1. Diagnostic signs
The periodontal probe placed horizontally on the mucosa determines a mucogingival line located less than 2–3 mm from the gingival margin. The periodontal probe determines a sulcular gingival height of 2 to 3 mm.
– The attached gingiva is absent. This situation is common.
3.2.2. Action to be taken
Regardless of the tooth movements, it is necessary to recreate an attached gingival environment. The objective of root coverage remains secondary to the notion of gingival thickening.
The recommended technique will be a buried connective tissue graft technique or, at the level of the mandibular incisors, an epithelioconnective tissue graft.
3.3. Bone level below the coronal half
3.3.1. Diagnostic signs
Loss of attachment is assessed by the radiological image of the bone level. This radiological image is correlated with mobility and the presence or absence of attached gingiva.
3.3.2. Mulheman Mobility Index
- 0: Ankylosis.
- I: Physiological mobility of firm tooth.
- II: Increased mobility, but the displacement is less than 1 mm in the vestibulo-lingual direction.
- III: The tooth can be moved +1 mm in the horizontal direction, but not in the apical direction. The function is not impaired.
- IV: Tooth displacement in the vertical direction. Disturbed function.
The differential diagnosis between mobility II and III is based on the gingival reaction to coronal displacement.
If the gum whitens during the mobility test, it will be classified as mobility III.
3.3.3. Conduct to be adopted
If attached gingiva is present and the mobility index is less than II, orthodontic movement is not contraindicated.
If the attached gingiva is absent and the mobility index is less than II, an attached gingival environment must be recreated by connective or epithelial-connective graft beforehand. This intervention also most often reduces mobility.
If the attached gingiva is absent and the mobility index is III or IV, orthodontic intervention is contraindicated and the conservation of the tooth is questioned.
The assessment of the attached gingiva is essential before any vestibulo-version movements. If it is present and of sufficient thickness, the orthodontist can work serenely regardless of the bone level, and the presence or absence of marginal tissue recession.
4. Conclusion
Diagnosis of a healthy and reliable periodontium is a prerequisite for orthodontic treatment. Traditional diagnostic tools remain relevant. They are simple and must be systematic. Inspection, palpation and radiographs guide the diagnosis. Periodontal probing specifies it and avoids any source of error. This examination is an essential act for the detection of an infectious periodontium.
When the periodontium is healthy, the orthodontist must ensure the quality and quantity of attached gingiva surrounding the teeth involved in the expansion movements.