Endodontic equipment
In modern practice, two basic devices are used for root canal diagnostics and treatment control:
- X-ray machine. Wall-mounted models are equipped with an articulated arm (pantograph) and a guiding tube (collimator) for targeted intraoral radiographs. They are essential for assessing canal curvature, controlling working length, and obturation quality.
- Apex locator. An electronic device that localizes the apical constriction. It forms an electrical circuit: the passive electrode (lip hook) is fixed to the lip mucosa, and the active one (clip) is attached to the endodontic file. The display shows the instrument's advancement. The APEX indicator lights up when the physiological apex is reached, and the OVER signal warns when the instrument enters the periodontium (overinstrumentation).
Instrument preparation and sterilization
Before sterilization, instruments are cleaned and thoroughly dried. The choice of method depends on the material type:
- Dry-heat sterilization (hot-air oven): instruments are packed in kraft paper bags or placed in trays using the "well" method.
- Steam sterilization (autoclave): optimal for dressing materials (in drums) and surgical handpieces (at 140 °C). The most reliable packaging is multi-layer vegetable parchment.
- Gas sterilization: used for endoscopes and hemisorption units.
- Chemical sterilization: formaldehyde and ethylene oxide gases (exposure 20 min) are used for heat-sensitive items (e.g., dental mirrors).
- Glass-bead sterilizer: used exclusively for small instruments (burs, endodontic files).
Dental handpieces require special care. For their disinfection, cleaning, and pressure lubrication, the Assistina device is used, and for express processing, the Terminator device. An alternative method is boiling in vaseline oil with centrifugation. Sterile instruments are stored on ultraviolet shelves.
Impression disinfection and sterility control
Impressions, mouthguards, and dental splints act as reservoirs for pathogenic microflora. They are rinsed with running water and disinfected (0.5% chlorhexidine, 6% hydrogen peroxide, 2% glutaraldehyde, MD-520 solution, or desoxon). Machine processing in Hygodjet or Nebucid units is possible.
Sterilization quality is checked in three ways:
- Chemical (thermal) control. Ampoules with substances melting at 110–200 °C are placed between instruments. Melting confirms that the required temperature has been reached.
- Bacteriological control. Cultures under aerobic and anaerobic conditions, as well as the use of test drums with spore-forming non-pathogenic flora.
- Biological indicators. Placed in boxes for continuous monitoring.
Important: viruses (including HIV), Mycobacterium tuberculosis, fungi, Vibrio cholerae, and tetanus endospores have high resistance, requiring intermediate- and high-level disinfectants.
Staff infection safety
The basic rule of dental care: any biological fluid is considered potentially infectious. High-risk procedures include manipulations with sharp instruments (needles, burs, scalpels).
Medical personnel are required to:
- Use personal protective equipment (PPE): masks, gloves, safety glasses, or plastic face shields.
- Wash hands thoroughly after examination, each procedure, and contact with infected material.
- Undergo annual medical check-ups (donate blood for HIV and markers of hepatitis A, B, C, D).
- Get vaccinated against hepatitis B and diphtheria twice a year.
When operating on urgent patients amid rising HIV infection rates, measures are intensified: double gloving and strictly disposable instruments are used.
To memorize chemical sterilization control substances, use the phrase: Big Incisor Accurately Amputated Affected Tissues (benzoic acid, resorcinol, antipyrine, ascorbic acid, pilocarpine, thiourea).
Class and exam questions
How does a dental apex locator work?
The device closes the electrical circuit through the patient's tissues. The passive electrode is attached to the lip, and the active one to the endodontic file. The indicator on the base unit lights up when the instrument reaches the physiological apex of the tooth.
How to properly sterilize dental handpieces?
They are cleaned and lubricated in special devices (e.g., Assistina) or boiled in vaseline oil followed by centrifugation. Surgical handpieces are steam autoclaved at a temperature of 140 °C.
Why and how are dental impressions disinfected?
Impressions serve as reservoirs for pathogenic microflora and can become a source of infection. They are rinsed with water and treated with antiseptics (e.g., 2% glutaraldehyde solution) manually or in special devices.
What else to study on this topic
- Structure of the X-ray machine: functions of the pantograph and collimator.
- Specifics of plasma and gas sterilization in dentistry.
- Algorithm for processing suture and dressing materials.
- Machine disinfection: operating principles of Hygodjet and Nebucid devices.
- Features of treating patients with HIV infection and viral hepatitis.
Master the entire topic in the «Propaedeutics of Dentistry» course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Dental equipment" and 868 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 65 video lessons on the subject
Other topics in the "Additional Topics" section
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.