Equipment Purpose & Maintenance
Quality Assurance and Infection Control Protocols
🎯 Learning Objectives
- Identify the components of the X-ray machine (Tubehead, Arm, Control Panel).
- Understand Infection Control protocols for digital sensors.
- Master Quality Control tests (Coin Test, Stepwedge).
- Define the purpose of Collimators and Filtration.
1. The X-Ray Machine Components
The dental X-ray machine consists of three primary sections. For the exam, you must know the function of each:
- The Tubehead: Contains the X-ray tube that produces dental X-rays. It is filled with oil to absorb heat.
- The Extension Arm: Suspends the tubehead and allows for movement/positioning. It houses the electrical wires.
- The Control Panel: Allows the operator to regulate the X-ray beam (kVp, mA, and time).
2. Digital Sensor Maintenance & Infection Control
Digital sensors are the most expensive pieces of equipment in the office. They cannot be heat-sterilized (autoclaved). Therefore, we follow strict “Barriers and Disinfection” protocols:
Protocol: Sensors must be covered with an FDA-cleared plastic barrier. After use, the barrier is removed, and the sensor is wiped with an intermediate-level disinfectant (EPA-registered) while taking care not to let liquid seep into the wire connection.
3. Quality Control (QC) Tests
How do we ensure the equipment is safe? We perform tests to check for consistency and light leaks:
| Test Name | What it Checks |
|---|---|
| Stepwedge | Checks for film contrast and machine output consistency. |
| Coin Test | Checks for safelight leaks in the darkroom. |
| Fresh Film Test | Checks for “fogged” or expired film. |
🚨 DANB EXAM ALERT: The Collimator
A Collimator is a lead plate with a hole in the center. Its job is to restrict the size and shape of the X-ray beam.
The Rule: The beam must be restricted to 2.75 inches at the patient’s skin. A rectangular collimator is safer than a round one because it reduces patient exposure by 60-70%.