Holding dental film (now primarily replaced by digital sensors, but the principle remains) with a finger during intraoral radiography is strongly discouraged due to the risk of unnecessary radiation exposure to the patient’s finger. While it might seem convenient, safer alternatives like film holders and bite blocks significantly minimize radiation to the patient and the dental professional. This article, informed by best practices in dental radiography, explores the risks associated with this practice, outlines safer alternatives, and addresses common questions surrounding radiographic techniques.
Understanding the Risks of Finger Holding
The Dose-Response Relationship in Radiation Exposure
The fundamental principle in radiography is ALARA – As Low As Reasonably Achievable. This means minimizing radiation exposure to both the patient and the operator. Holding the film or sensor with a finger directly violates this principle. The finger is exposed to the primary radiation beam, even if collimation is employed, resulting in a localized dose. While a single exposure might not cause immediate harm, cumulative exposures over time increase the risk of radiation-induced damage, including an elevated risk of skin cancer on the fingers.
Alternative Methods Prioritizing Safety
Modern dental radiography emphasizes the use of film holders or bite blocks. These devices allow the patient to hold the film or sensor in place without the need for a finger, minimizing the radiation dose to the hands. Different types of holders are available for various intraoral radiographs, including periapical, bitewing, and occlusal views. These holders also aid in proper alignment, reducing the need for retakes and further radiation exposure.
Safe Alternatives to Finger Holding
Film Holders and Bite Blocks
These devices come in various designs but share the common goal of keeping fingers away from the primary beam. Some popular examples include:
- XCP (Extension Cone Paralleling) holders: These holders ensure parallel alignment between the film/sensor and the long axis of the tooth, promoting accurate image geometry. They also feature an external aiming device that helps align the X-ray beam.
- Rinn Snap-A-Ray: This is a simple and reusable device suitable for bitewing and periapical radiographs.
- Bite tabs or adhesive tabs: These are typically used for bitewings and are attached directly to the film or sensor.
Using a Beam Aiming Device
Regardless of the type of holder used, a beam aiming device is crucial. This device attaches to the X-ray tube head and aligns it with the holder, ensuring the beam is directed at the film/sensor accurately. This minimizes the chance of cone cutting (where part of the image is missing) and reduces unnecessary radiation to the patient.
Best Practices for Radiographic Technique
Proper Collimation and Filtration
Collimation restricts the size of the X-ray beam to the area of interest, reducing scatter radiation and minimizing exposure to surrounding tissues. Rectangular collimation is preferable to round collimation as it further reduces the beam size. Filtration removes low-energy X-rays that are absorbed by the patient but do not contribute to image formation. These low-energy photons increase the radiation dose without providing any diagnostic benefit.
Using the Fastest Film Speed or Digital Sensor Sensitivity
Faster film speeds (e.g., F-speed) or more sensitive digital sensors require less radiation to produce a diagnostic image. Upgrading to these technologies can significantly reduce patient exposure. Digital radiography also offers the advantage of instant image display, which allows for immediate assessment and reduces the need for retakes.
Protective Barriers and Personal Protective Equipment
Dental professionals should always stand behind a protective barrier during X-ray exposure. If a barrier is not available, they should stand at least six feet away from the patient and the X-ray tube head, at an angle of 90 to 135 degrees to the primary beam. Personal protective equipment (PPE), such as lead aprons and thyroid collars, should be provided to all patients.
Frequently Asked Questions (FAQs)
FAQ 1: Why is finger holding specifically discouraged?
Finger holding places the finger directly in the path of the primary X-ray beam. Skin cells are relatively radiosensitive, making the finger susceptible to radiation damage and increasing the risk of skin cancer with repeated exposure. The goal is to minimize ANY unnecessary radiation.
FAQ 2: Are there any situations where finger holding might be considered?
No. There are no justifiable situations where finger holding is considered acceptable in modern dentistry. Safe and effective alternatives are readily available. The benefits never outweigh the risks.
FAQ 3: What are the legal and ethical implications of finger holding?
Dentists have a legal and ethical responsibility to protect their patients from unnecessary harm. Finger holding could be considered negligence and could lead to legal repercussions. The ethical obligation to follow ALARA principles further reinforces the prohibition of this practice.
FAQ 4: How do film holders improve image quality?
Film holders promote consistent film or sensor placement and alignment, leading to more accurate and diagnostic images. They reduce distortion and elongation, which can occur if the film or sensor is not parallel to the tooth.
FAQ 5: What if a patient refuses to use a film holder?
Explain the importance of using a holder to minimize radiation exposure. Offer alternative types of holders and take the time to demonstrate how they work. Document the patient’s refusal in their record and consider the diagnostic necessity of the radiograph before proceeding. Weigh the benefits of the X-ray against the potential (however unlikely) harm. If it can be avoided, it should be.
FAQ 6: How should I clean and sterilize film holders?
Film holders should be cleaned and sterilized according to the manufacturer’s instructions. Typically, this involves disinfection with an intermediate-level disinfectant or sterilization in an autoclave. Proper infection control protocols are essential to prevent cross-contamination.
FAQ 7: Can I use digital sensors with the same film holders?
Yes, many film holders are designed to accommodate both traditional film and digital sensors. However, you may need to use specific holders or adapters that are designed for your particular sensor type.
FAQ 8: What is the best way to position a film holder for a bitewing radiograph?
Ensure the patient bites down firmly on the bite block or tab. The film/sensor should be positioned to capture the distal of the canine and all premolars and molars on both the maxilla and mandible. The central ray should be directed through the contact points of the teeth.
FAQ 9: How do I position a film holder for a periapical radiograph?
The film/sensor should be positioned to capture the entire tooth and at least 2-3 mm of periapical bone. The long axis of the tooth should be parallel to the film/sensor (using a paralleling technique when possible), and the central ray should be directed perpendicular to the film/sensor.
FAQ 10: What is the “cone cutting” and how can I avoid it?
Cone cutting occurs when the X-ray beam is not properly aligned with the film/sensor, resulting in a portion of the image being missing. Using a beam aiming device and ensuring proper alignment of the X-ray tube head with the film holder can prevent cone cutting.
FAQ 11: How often should dental X-ray equipment be inspected and calibrated?
Dental X-ray equipment should be inspected and calibrated annually to ensure proper functioning and radiation safety. This includes checking the output of the X-ray tube, the collimation, filtration, and the timer accuracy.
FAQ 12: Are there any resources available for further education on dental radiography safety?
Yes, numerous resources are available, including professional organizations like the American Dental Association (ADA), the American Academy of Oral and Maxillofacial Radiology (AAOMR), and state dental boards. These organizations offer continuing education courses, guidelines, and recommendations on best practices in dental radiography. Also, reputable dental supply companies often provide training and support on their radiographic products.