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References
Part 2: Studies

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Study #1: A Comparative Study of Muscle Activity in Instrumentation Techniques

The first of these studies, "A Comparative Study of Muscle Activity in Instrumentation Techniques", was completed in 1993 at the UTHSCSA Dental School in collaboration with Lee Grayson, RDH, and Dr. John Rugh in the Department of Orthodontics. The complete study is published in Chapter Three of Dr. Meador's textbook, Ergonomics in Pain Management for Dental Professionals Including Carpal Tunnel Syndrome, which can be purchased in hard copy from the Office of Continuing Dental Education of the UTHSCSA Dental School in San Antonio, TX. The book is also available on the web at http://smile.uthscsa/edu. The article, "The Impact of the BioCentric Technique on Pain, Productivity, and Attitude of Dental Hygienists," was published in the January/February 1997 issue of Practical Hygiene and contained truncated versions to two papers, i.e. "A Comparative Study of Muscle Activity in Instrumentation Techniques," and "The Impact of the BioCentric Technique on Pain, Productivity, and Attitude of Dental Hygienists."

A VERY BRIEF SUMMARY OF THE STUDY FOLLOWS:

PURPOSE. The possible link between occupational pain in dental hygienists and instrumentation techniques is a subject of considerable interest. The purpose of this study was to evaluate the differences in patterns of muscle activity in instrumentation techniques, to better understand the impact on the practicing hygienist, and how it relates to occupational pain.

METHODS. The hygienist in this case study was skilled in two instrumentation techniques, each based on different ergonomic and orthopaedic principles. Nineteen surface electrodes were placed on the muscle groups of the shoulder, upper arm, forearm, two long fingers and thumb.
Muscle activity in six motions common to the two techniques was recorded on an eight channel J & J model I-330 EMG system.
The results were printed in eight tables. Four tables presented the tracings (of muscle contractions), and four tables presented the means and standard deviations for the tracings.

RESULTS. The intensity (frequency and magnitude) of contractions of the muscle groups was well defined. Each of the four motions (power strokes) common to the BioCentric Technique showed a distinctly different pattern of activity of the arm and shoulder muscles. The two motions common to the Currently Accepted Techniques showed almost identical patterns of activity of the arm and shoulder muscles.

CONCLUSIONS. The results of this case study are consistent with the theory that motions utilizing the same muscles cause unnecessary fatigue.
The similarity in patterns of muscle activity of the two motions in the currently accepted techniques may contribute to fatigue and pain as observed in the clinical hygienist. The consequences are well documented in the literature.
The difference in patterns of muscle activity of the motions used in the BioCentric Technique explains how the operator can shift back and forth between motions and extend the length of a work session indefinitely without undue fatigue. Similar results and conclusions were seen in the thumb and fingers.
Violating neutral and exhausting vital muscle groups are the major causes of occupational pain. Fatigue and pain are not normal in the healthy body. They are the body's way of telling us something is wrong. We should "listen to our body" and respond to any "cry for help." The author likes to say that if there were a dictionary for "Body Language" it would have only two words, fatigue and pain. Our body will tell us, with fatigue and pain, if we are in violation of the Law of Neutrality, which is just as exacting as the Law of Gravity. The only difference is lag time.

KEY WORDS. Carpal tunnel syndrome, occupational pain, ergonomic and orthopaedic principles in periodontal instrumentation, neutrality of joints, muscle dynamics, instrument grasp/grip.

CARDINAL POINTS. The BioCentric Technique is based on two points:
1) Maintaining neutrality of the joints of the upper extremity, and
2) Avoiding exhaustion of vital muscle groups.

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Study #2: The Impact of the BioCentric Technique on Pain, Productivity, and Attitude of Dental Hygienists

The second validating study, The Impact of the BioCentric Technique on Pain, Productivity, and Attitude of Dental Hygienists, was done in 1995 at the UTHSCSA Dental School in collaboration with Dr. Douglas Murphy in the Department of Educational Research and Development, and is found in Chapter Four of Dr. Meador's textbook. The article, "The Impact of the BioCentric Technique on Pain, Productivity, and Attitude of Dental Hygienists" was published in the January/February 1997 issue of Practical Hygiene and contained truncated versions of two papers, i.e. "A Comparative Study of Muscle Activity in Instrumentation Techniques", and "The Impact of the BioCentric Technique on Pain, Productivity, and Attitude of Dental Hygienists."

 

THE PURPOSE of the study was to determine the extent participants were helped by the course "Instrumentation for the Hygienist to Manage Ocupational Pain Including Carpal Tunnel Syndrome." Between 1991 and 1995, 180 hygienists had taken the course. Questionnaires were mailed to 149 valid addresses, with a 33% response.

DESCRIPTION OF THE STUDY The study was done with a twenty-one page retrospective questionnaire containing 56 questions and a one-page narrative.

RESPONDENTS 67% were full-time hygienists. The rest were part-time hygienists, and those working in institutional facilities or in dental hygiene education. 51% had worked full-time for a mean of 11.5 years. Most of the respondents were working full weeks (four to six days per week).

BEFORE THE COURSE The level of work pain was reported on a scale ranging from O (no pain) to 5 (severe and constant pain). Pain levels were catagorized into three groups: O - No Pain (12%); 1 and 2 - Low Pain (29%); and 3, 4, and 5 - High Pain (57%).

PAIN AND SYMPTOMS 86% reported work-related pain before they took the course. Eight symptoms were listed, i.e. fatigue, tingling, numbness, loss of strength, night pain, work pain, swelling and carpal tunnel syndrome. Most symptoms were in resondents' hands, fingers, thumb and fewer symptoms were experienced in their neck, shoulder , and back.
On the average, respondents reported that they experienced symptoms three and four days per week. 47% were forced to space difficult cases and many could not work consequetive days. 17% considered ambidextrous gloves as contributing to their problems. Leisure activities were affected for 65%, including all sports, househould duties, personal activities, etc.

AFTER THE COURSE. 67% reported improvement in symptoms within four weeks. Some as soon as one week. 94% were helped. Instrument sharpening helped 82%, which made calculus removal easier for 71% and 61% experienced increased tactile sensations.

34% reported increased production due to having less fatigue and pain. They found they could work heavier schedules for more consecutive days and and longer hours. One hygienist in Long Island, that had been having serious problems, said (paraphrase) "I feel as though I could work six days a week for the rest of my life, and be in hog-heaven."

There were improved attitudes toward work for 74% and and personal life for 63%, because 63% reported they could resume leisure activities that they had been denied by pain. 86% adopted the BioCentric Technique, as either the major or a minor part of their technique. A few adopted it 100%.
Three factors limited the integration of these skills, i.e. 1) an oppressive work load that would not allow the hygienist additional time for difficult cases. (It is necessary to have at least fifteen minutes extra time for difficult cases for a month in order to complete this skill transfer.); 2) a negetive work environment. The patient's chair is the most significant obstacle, while, carpeted floors, rear-delivery instrument systems that block the 12 o'clock chair position, inadequate instruments and sharpening stones, etc. add to but do not complete the list; and 3) old habits. Some individuals experience greater difficulty than others in dealing with this very perplexing problem. However, the author has seen hygienists that could not manage the moves at the hands-on session, but a year later, with no additional instruction, were able to perform remarkable well.

This study confirmed the fact, as observed clinically and confirmed in the literature, that for many hygienists, life is a litany of pain. Pain, in this case, is a symptom of dysfunctional work habits. It is a cumulative condition and compounded by time. Unfortunately, working in pain over time is not without risk, and nurological tissues, when severely damaged, are the least reparable tissues of the body.

However, significant help was reported by the majority of respondents. The benefits of the BioCentric Technique as seen by these hygienists are increased comfort in the workday. This can extend careers, increase production and improve the attitude toward work and enjoyment of leisure time. This is all made possible when the body is kept in neutral and muscle exhaustion is avoided in an ergonomically friendly work place.
This was rewarding to the author, as his interest in this matter has been simply to help the hygienist that is in pain. He likes to think of himself as the "Wounded Healer."

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