Where is the periodontium located and what is its structure?
The periodontium is located in the space between the tooth root cementum and the alveolar bone tissue. Histologically, it is a dense fibrous connective tissue rich in cells (fibroblasts, cementoclasts), as well as collagen and elastic fibers.
The structural basis consists of thick bundles of collagen fibers, the orientation of which varies depending on the area. The key fixation elements are «transitional» (principal) fibers: they emerge from the cementum, cross the periodontal space, and embed into the alveolar bone. Around the neck of the tooth, the circular dental ligament is located, which features a particularly high concentration of such transitional fibers.
What runs through the periodontium and what are its functions?
The periodontal tissue is richly vascularized and innervated. It contains:
- Blood vessels;
- Lymphatic vessels;
- Nerve fibers — forming various sensory endings.
Due to this structure, the periodontium performs the following functions:
- Mechanical — attachment of the tooth to the jaw;
- Shock-absorbing ( cushioning) — dampening the pressure on the jawbone during masticatory loading;
- Sensory — provided by nerve fibers and sensory endings.
How does the periodontium appear on an X-ray?
Normally, on an X-ray image, the periodontium is visualized as a uniform dark strip 0.2–0.25 mm wide. This shadow follows the contours of the root cementum and the dental alveolus.
When pathological processes develop, the picture changes. For example, in chronic granulating periodontitis, widening of the periodontal ligament space or the appearance of round or flame-shaped areas of bone resorption at the root apex may be observed.
Clinical significance: periodontitis
Inflammation of the periodontium is called periodontitis. Apical periodontitis occurs when the periodontium becomes infected due to untreated or inadequately treated pulpitis; pulp decay products, microorganisms, and their toxins penetrate the apical periodontium and cause inflammation.
- Acute apical periodontitis is characterized by constant pain that worsens when touching or biting down on the causative tooth. The "elongated tooth" symptom is typical.
- Chronic granulating periodontitis may present with minor discomfort, periodic aching pain, and the formation of a fistula on the gingiva or face.
- Marginal periodontitis is accompanied by pain localized in the gingival margin area.
The key causative agent of the infection is Aggregatibacter actinomycetemcomitans (detected in 25–30% of cases), along with other periodontopathogenic bacteria (Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia).
Principles of treatment for periodontal inflammation
Treatment objectives include targeting the microflora of macro- and microcanals, eliminating the inflammatory process in the periodontium, and stimulating reparative processes in the periodontium and adjacent bone tissue. Endodontic treatment involves instrumentation and medicinal treatment of the root canal followed by its filling.
For precise treatment, the working length of the tooth must be determined. The true length of the canal is calculated from the radiograph with an instrument inserted using the formula: K = (i × K₁)/i₁ (where i is the actual length of the instrument, K₁ is the radiographically determined length of the canal, and i₁ is the radiographically determined length of the instrument).
In acute periodontitis proceeding with a normergic type of reaction, antibiotics are generally not prescribed. Their use is justified only in debilitated patients with a sluggish inflammatory response or in complicated cases accompanied by intoxication.
Class and exam questions
What is the «elongated tooth» symptom and when does it occur?
In the materials, it is referred to as the sensation of an «elongated tooth». This symptom is characteristic of acute apical periodontitis and may also occur in acute purulent osteomyelitis.
How to distinguish the pain of acute pulpitis from that of periodontitis?
In pulpitis, the pain is sharp, paroxysmal, spontaneous, and intensifies at night and from thermal stimuli. In periodontitis, the pain is constant, aching, intensifies upon touching and biting, and the floor of the carious cavity is painless upon probing.
Are antibiotics prescribed for acute periodontitis?
According to standard tactics, antibiotics and sulfonamides are not prescribed, as the inflammation usually proceeds as a normergic reaction. They are indicated only for debilitated patients or in complicated courses with intoxication to prevent the spread of inflammation to surrounding tissues.
What else to study on this topic
- Cementum of the tooth root (Cementum)
- Dental pulp and pulpitis
- Bone tissue of the alveolar process
- Endodontic root canal treatment
Study the complete topic in the Anatomy course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on «Periodontium» and 1,363 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 295 video lessons by subject
Other topics in the "Anatomical Structures" section
Entire "Anatomical Structures" sectionFree video lessons: AnatomyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.