PART I | The Dental Operating Microscope |
The Role of the Microscope in Modern Endodontic Practice
Before considering ergonomics and operatory design, we should clarify our ultimate objective. Briefly, in an ideal ergonomic practice, all procedures are performed under the microscope, even those that do not require a microscope to be performed competently. For example, screening a patient for oral cancer, administering anesthesia, and checking occlusion are procedures that are not typically thought to need magnification. The important question is not whether the microscope is required to perform a task but rather, in performing one set of tasks with the microscope and another set without it, is ergonomic efficiency negatively affected? The answer to that question is almost always “yes.”
Working in an environment where the microscope is constantly being moved into and out of the field is extremely inefficient and tends to be very distracting for the doctor, the assistant, and even the patient. Such a practice model fragments continuity of care, reduces focus on the task at hand, and often requires the use of Classes III, IV, and V motions (described later), thus dramatically decreasing both health and efficiency. For these reasons, we have come to understand that if the clinician can learn to incorporate ergonomic techniques and perform all procedures under the microscope—whether magnification is needed or not—then efficiency, focused concentration, competence, teamwork skills, and job satisfaction are all enhanced.
Understanding Basic Ergonomic Principles
Ergonomics is the science of maximizing human performance and well-being and involves a study of both human excellence and health. Proper ergonomic design is necessary to prevent repetitive strain injuries and other musculoskeletal disorders, which can develop over time and lead to long-term disability. Box 1-1 summarizes the benefits of implementing ergonomic science into operatory design.
Box 1-1 | Benefits of implementing ergonomic science into operatory design |
• Stress reduction
• Reduction in repetitive motion injuries
• Healthy posture
• Elimination of burnout
• Enhancement of clinical excellence
• Maintenance of optimal mental outlook
• Time-motion efficiency
• Healthy practice culture
• Elimination of disability
• Efficient office design
• Safety
• Performance consistency
• Retention of talented staff
• Reduction of fatigue
Ergonomic classes of motion
Ergonomic science classifies the kinds of motions required to perform a specific task. Generally, a task that can be completed using a single class of motion is more efficient than the same task performed with multiple classes of motion. For example, passing a mirror using just a Class I motion is far more efficient than using a combination of Classes I, II, III, IV, and V motions. Table 1-1 summarizes the classifications of motion, and there are several videos available on YouTube demonstrating how they impact efficiency and performance during endodontic procedures.1
Table 1-1 | Classifications of motion |
Class I | Moving only the fingers |
Class II | Movement from the wrist |
Class III | Movement from the elbow |
Class IV | Movement from the shoulder |
Class V | Movement from the waist |
In endodontics, proper ergonomic design criteria are based on the goal of reducing Classes III, IV, and V motions while producing a healthy and injury-free environment where Class I and Class II motions predominate. With proper training, discipline, and teamwork, it is possible to perform nearly all endodontic procedures under a microscope using only Class I and Class II motions, with only an occasional need for Class III motion. Once this skill is mastered, the clinician will reap the benefits of increased productivity, heightened competence, stress reduction, postural balance, and an enhanced practice culture of focused teamwork.
Executing efficient ergonomics is a habit that is mastered through repetitive training. While bad habits are difficult to break once formed, good habits and proper technique can become part of routine practice in a short period of time. A clinician or an assistant can learn the required skills if there is effortful practice and a work environment conducive to learning and mastering a new skill set.
Key design parameters of ergonomic operatory design
Operatory design and ergonomic technique go hand in hand. Even if the clinical team is practiced and wellversed in proper ergonomic skills, it is almost impossible to execute good ergonomic practice if the operatory does not reflect proper ergonomic design.
The circle of influence, a key principle in both operatory and front office design, posits that all instruments (ie, armamentaria, recordkeeping devices, viewing monitors) involved in the delivery of care should require nothing more than a Class III motion for both the doctor and the assistant (Fig 1-1). Employing such a principle places significant constraints on operatory and front office designs. Additionally, the operatory should be designed with sight angles so that there is little need to turn one’s head to view monitors, use keyboards, or procure accessory devices.
Fig 1-1 (a) Aerial view of the circle of influence design principle. View of the doctor’s (yellow circle) and the assistant’s (red circle) respective circles of influence. (b) The circle of influence design principle states that all required instruments and devices are within easy reach.
There are nine key elements that are required to realize good ergonomic operatory design (Table 1-2). The following sections describe each one briefly and discuss its role in ergonomics.
Table 1-2 | Nine elements required for good ergonomic operatory design |
Element | Requirement |
Microscope parameters | Six-step or zoom with lowest magnification down to 2.2× |
Patient chair and headrest | Must be freely movable (rotation) and without a headrest |
Doctor and assistant stools | Dual adjustable (height and angle) armrests, adjustable lumbar support |
Microscope mounting | Wall, ceiling, floor mounts |
Assistant/co-observation scope | Adjustable, dual-axis (not single-axis) co-observat... |