Dental Laboratory

Basic equipment and office zoning

The dentist's medical space is strictly regulated and divided into several functional zones, each of which requires specific equipment.

Primary and auxiliary equipment The core of the office is the dental unit, supplemented by the patient chair, work stools for the specialist and their assistant, and an instrument table. Auxiliary equipment is used for complex diagnostic and therapeutic procedures: microscopes, apex locators, negatoscope viewers, curing lights, amalgam mixers, and electronic data processing systems.

Infection control system Safety of the appointment is ensured by strict compliance with sanitary standards. The office is equipped with separate sinks for handwashing and instrument cleaning, and containers with disinfectant solutions. The sterilization unit includes:

• Autoclaves and dry-heat sterilizers.
• Ultrasonic baths and glass bead sterilizers.
• Devices for automatic cleaning and lubrication of handpieces (e.g., Assistina, Terminator).
• Ultraviolet shelves, germicidal quartz lamps, and fume hoods.

To maintain pharmaceutical order in the office, specialized medical furniture is installed: cabinets for filling materials, a separate class "A" safe for toxic substances and a class "B" cabinet for storing potent drugs, as well as an emergency first-aid kit.

Historical path of dental machines

Before the advent of mechanized devices, carious cavities were treated with primitive manual instruments—files, scrapers, and bow drills.

Evolution of rotary instruments:

1. Manual era (1684). Surgeon C. Solingen developed a long shaft with a faceted handle and a working part shaped like a cone or a sphere. The instrument was rotated by fingers and was actively used until the mid-19th century. In 1820, M. Delabar introduced an improved hand drill.
2. Mechanical drive (1864). J. Harrington created a device with a mainspring. A single winding lasted for 2 minutes of deafeningly noisy work, yet the preparation speed increased colossally: 10 minutes of work with the spring mechanism replaced an hour of manual labor.
3. Foot pedal (1871). American J. Morrison patented a revolutionary tripod with a pedal, flywheel, and flexible sleeve. The dentist pressed the pedal, the flywheel spun up and transmitted rotation to the bur via a belt drive.
4. Electrification and turbines. The appearance of electric motors became a new milestone. Later, turbine dental drills were introduced, where the rotor is rotated not by current, but by a directed flow of compressed air supplied by a compressor.

In historical retrospective, rotation was transmitted via rigid sleeves (as in the Chiradent-512 unit), consisting of metal rods and cords. Due to their rigidity, they severely restricted the dentist's movements. In modern combined systems (e.g., US-30) and new units, exclusively flexible sleeves are used, where all moving elements are hidden in an ergonomic protective hose.

Architecture of the modern dental unit

The modern workplace implies "four-handed" treatment (dentist and assistant). The unit is functionally divided into three main modules:

1. Dentist's block It is an instrument panel with a touch control panel for managing the chair and water unit. The basic configuration includes:

• Three-way syringe (water and air spray handpiece).
• Ultrasonic scaler for endodontics and calculus removal.
• Curing light for light-cured materials.
• Micromotor handpiece (for polishing and low-speed work).
• High-speed turbine handpiece.

Instrument delivery types:

• Over-the-patient delivery: hoses come down from above. This prevents the handpiece from dropping to the floor and reduces the weight load on the dentist's hand.
• Traditional (hanging hose) delivery: hoses hang downward. Features a longer reach (convenient for working at the head of the chair), no pull-back tension, and a freer control panel.

2. Assistant's unit Ensures cleanliness and visibility of the surgical field. It houses the saliva ejector (for removing saliva and water), high-volume evacuator (for removing water aerosol from handpieces), auxiliary syringe, curing light, and a duplicate control panel.

3. Hydro-unit and lighting Includes the cuspidor bowl and an automatic cup-filler system (controlled from any panel). The operational field is illuminated by a shadowless lamp, which can be mounted on the unit itself, the ceiling, or a separate stand.

Workplace Ergonomics

The physician's health and patient comfort directly depend on the proper selection of furniture.

• Patient chair. Equipped with an electromechanical or hydraulic drive. Allows treatment in supine or semi-supine positions. Capable of rising to a height of up to 480 mm and supporting a load of at least 150 kg. Settings are adjusted via control panels, buttons on the backrest, or a foot pedal.
• Dentist's stool. Can be traditional or saddle-style. The latter is recognized as the most anatomical: it automatically supports an upright posture, prevents dorsalgia (back pain), and serves as prevention against professional joint pathologies.
• Assistant's stool. Structurally characterized by a special footrest ring. A strict ergonomic rule: the assistant sits 15–20 cm higher than the doctor to maintain visibility of the operating field without blocking the view.
• Dentist's cart. Most commonly implemented as a mobile cart with drawers for storing small instruments; less frequently, it is mounted directly onto the dental unit.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Classification and design of dental handpieces
• Operating principles of vacuum systems: saliva ejectors and high-volume evacuators
• Protocols for pre-sterilization cleaning and automated instrument lubrication
• Properties and operational modes of curing lights
• Functionality of apex locators in endodontic treatment

Other topics in "Chapter 2. Organization of Dental Practice"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.