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The Journal and the metric system
EDITORIAL
The Journal and the metric system
I
n an accompanying editorial, California’s J. Rodney Mathews emphasizes the importance of early orthodontic adoption of the metric system of weights and measures. It is not likely that many orthodontists realize how rapidly it is being accomplished in the scientific world. Not long ago, the President signed the Metric Conversion Act, which will make the International Metric System the predominant, though possibly not the exclusive, system of measurement throughout the country. Bringing it to pass will require cooperation in many areas of the scientific community. A smooth transition to the metric system in orthodontics will depend on its adoption by teachers, manufacturers, and publishers. The JOURNAL'S contribution will be a gradual insertion in all articles of thc$ proper metric values along with those customarily expressed in inches. The following self-explanatory conversion table will be used for the measurements most commonly used in orthodontics :
Thousandths 0.005 0.008 0.009 0.010 0.011 0.012 0.014 0.016 0.018 0.020 0.021 0.022 0.024 0.025 0.026 0.028 0.030 0.040 0.045 0.050
of
an inch
Uillimeters
inch inch inch inch inch
0.1270 0.2032 0.2286 0.2540 0.2794
inch inch inch inch inch inch inch inch inch inch inch inch inch inch inch
0.3048 0.3556 0.4064 0.4572 0.5080 0.5334 0.5588 0.6096 0.6350 0.6604 0.7112 0.7620 1.0160 1.1430 1.2700
Eozlnded rake
millimeter millimeter millimeter millimeter
0.127 0.203 0.229 0.254
millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter
0.279 0.305 0.356 0.406 0.457 0.508 0.533 0.559 0.610
millimeter millimeter millimeter millimeter millimeters millimeters millimeters
0.635 0.660 0.711 0.762 1 .016 1.143 1.270
in millimeters millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeters millimeters millimeters 455
456
Editorial
Am. J. Orthod. October1976
In calculating the table, 39.37 inches was considered to be the equivalent of 1 meter. The rough equivalent of 1 inch, therefore, is 25.4 millimeters. The rounded values can be considered sufficiently close approximations for our purposes in orthodontics. If another size in millimeters is wanted, it can be determined by multiplying the value expressed in thousandths of an inch by 25.4. Dr. Mathews also suggests that the time has come for graduate orthodontic departments to start teaching and using the metric system. It can be used together with the English inch system for as long as seems necessary. It won’t take long, for most of the states already require that the metric system be taught in the public schools. Tomorrow’s graduate students will soon find the old English system of measurements even more confusing to them than the metric system is to today’s orthodontists. Orthodontics successfully surmounted a previous experience in a change-over in determining the size of wires. At one time, the diameter of a wire was listed by gauge number. If we remember correctly, gauge 19 later became 0.036 inch, and gauge 17 was 0.045 inch in diameter. How quickly we forget ; they may have been reversed. The day will come when inch values will also become a part of the dim past. Orthodontic manufacturers’ contribution during today’s transitional period should be a conversion policy in which the metric as well as the English values are printed on all of their products. Firms with foreign branches in Europe-and this includes most of the larger orthodontic companies-will have to go metric by 1979 or they will be excluded from the European Common Market. Just what is the metric system! It can be, defined as a decimal system of weights and measurements. The fundamental unit of length is the meter (39.37 inches), the unit of weight is the kilogram (22.046 pounds), and the unit of capacity is the liter (0.9081 dry quart or 1.0567 liquid quarts). Other units are formed by the addition of prefixes. Examples are the millimeter (one thousandth of a meter) and the centimeter (one hundredth of a meter), the kilometer (1,000 meters), the megameter (one million meters), and the micron (one millionth of a meter, or one thousandth of a millimeter). Strangely, the United States was the first English-speaking country to make the metric system legal (in 1867)) but we have since been lagging behind England in shifting to metric. So far, metrication has been voluntary but not universal. The new United States Metric Conversion Act established a federal Metric Board to coordinate conversion to the metric system within the next 10 years. Among its duties will be to provide a program of public information and education for all elements of society, for England’s experience has been one of confusion and suspicion about metrication and metric calculations by the public at large. It is being accepted more readily by scientific societies, but progress has been so slow that they also have been producing metric education material for their members. The change-over in the JOURNAL will also be slow, since the monthly issues are in preparation far in advance of the month of issue. It will be experimental and irregular at first but, in all likelihood, permanent in the long run.
B. F. D.
The Journal and the metric system
I
n an accompanying editorial, California’s J. Rodney Mathews emphasizes the importance of early orthodontic adoption of the metric system of weights and measures. It is not likely that many orthodontists realize how rapidly it is being accomplished in the scientific world. Not long ago, the President signed the Metric Conversion Act, which will make the International Metric System the predominant, though possibly not the exclusive, system of measurement throughout the country. Bringing it to pass will require cooperation in many areas of the scientific community. A smooth transition to the metric system in orthodontics will depend on its adoption by teachers, manufacturers, and publishers. The JOURNAL'S contribution will be a gradual insertion in all articles of thc$ proper metric values along with those customarily expressed in inches. The following self-explanatory conversion table will be used for the measurements most commonly used in orthodontics :
Thousandths 0.005 0.008 0.009 0.010 0.011 0.012 0.014 0.016 0.018 0.020 0.021 0.022 0.024 0.025 0.026 0.028 0.030 0.040 0.045 0.050
of
an inch
Uillimeters
inch inch inch inch inch
0.1270 0.2032 0.2286 0.2540 0.2794
inch inch inch inch inch inch inch inch inch inch inch inch inch inch inch
0.3048 0.3556 0.4064 0.4572 0.5080 0.5334 0.5588 0.6096 0.6350 0.6604 0.7112 0.7620 1.0160 1.1430 1.2700
Eozlnded rake
millimeter millimeter millimeter millimeter
0.127 0.203 0.229 0.254
millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter
0.279 0.305 0.356 0.406 0.457 0.508 0.533 0.559 0.610
millimeter millimeter millimeter millimeter millimeters millimeters millimeters
0.635 0.660 0.711 0.762 1 .016 1.143 1.270
in millimeters millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeter millimeters millimeters millimeters 455
456
Editorial
Am. J. Orthod. October1976
In calculating the table, 39.37 inches was considered to be the equivalent of 1 meter. The rough equivalent of 1 inch, therefore, is 25.4 millimeters. The rounded values can be considered sufficiently close approximations for our purposes in orthodontics. If another size in millimeters is wanted, it can be determined by multiplying the value expressed in thousandths of an inch by 25.4. Dr. Mathews also suggests that the time has come for graduate orthodontic departments to start teaching and using the metric system. It can be used together with the English inch system for as long as seems necessary. It won’t take long, for most of the states already require that the metric system be taught in the public schools. Tomorrow’s graduate students will soon find the old English system of measurements even more confusing to them than the metric system is to today’s orthodontists. Orthodontics successfully surmounted a previous experience in a change-over in determining the size of wires. At one time, the diameter of a wire was listed by gauge number. If we remember correctly, gauge 19 later became 0.036 inch, and gauge 17 was 0.045 inch in diameter. How quickly we forget ; they may have been reversed. The day will come when inch values will also become a part of the dim past. Orthodontic manufacturers’ contribution during today’s transitional period should be a conversion policy in which the metric as well as the English values are printed on all of their products. Firms with foreign branches in Europe-and this includes most of the larger orthodontic companies-will have to go metric by 1979 or they will be excluded from the European Common Market. Just what is the metric system! It can be, defined as a decimal system of weights and measurements. The fundamental unit of length is the meter (39.37 inches), the unit of weight is the kilogram (22.046 pounds), and the unit of capacity is the liter (0.9081 dry quart or 1.0567 liquid quarts). Other units are formed by the addition of prefixes. Examples are the millimeter (one thousandth of a meter) and the centimeter (one hundredth of a meter), the kilometer (1,000 meters), the megameter (one million meters), and the micron (one millionth of a meter, or one thousandth of a millimeter). Strangely, the United States was the first English-speaking country to make the metric system legal (in 1867)) but we have since been lagging behind England in shifting to metric. So far, metrication has been voluntary but not universal. The new United States Metric Conversion Act established a federal Metric Board to coordinate conversion to the metric system within the next 10 years. Among its duties will be to provide a program of public information and education for all elements of society, for England’s experience has been one of confusion and suspicion about metrication and metric calculations by the public at large. It is being accepted more readily by scientific societies, but progress has been so slow that they also have been producing metric education material for their members. The change-over in the JOURNAL will also be slow, since the monthly issues are in preparation far in advance of the month of issue. It will be experimental and irregular at first but, in all likelihood, permanent in the long run.
B. F. D.