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Alterations produced in dental enamel by orthodontic appliances
Am. J. Orthod. Omhr 1983
tivity. A total of 100 taps in each direction resulted in 88 SPs and 53 jaw jerks downward, and 61 SPs and 34 jaw jerks backward. The upward taps elicited ‘75 SPs and 38 jaw jerks. Not only the duration of the silent period but all reflex responses were remarkably inconsistent , despite standardized and controlled conditions. It is concluded that the duration of the SP is not a feasible diagnostic criterion for temporomandibular joint dysfunction. T. M. Graber
Alterations Orthodontic
produced in Dental Enamel by Appliances
C. Klein de Tolcachir C. J. Dent.
Res.
93:5/4,
1983
The objectives of this study were to assessthe relative effect of different orthodontic appliances on the enamel surface of teeth involved in orthodontic therapy. Conclusions are based on a previous report given in Lyon, France, covering a 20-year period, plus the author’s own 12-year didactic and clinical experience. Patients from the University clinic were divided into three groups according to the type of orthodontic appliances being used. Group A was treated with removable appliances; Group B consisted of patients with conventional orthodontic multibanded appliances cemented to the teeth; Group C was made up of patients with brackets bonded directly to the teeth. Assessments were made before, during, and after orthodontic treatment. Plaque and attacks on the enamel surfaces can be prevented by proper oral hygiene. In Group A, good results were achieved in 90% of the cases, although caries continued to occur. This was attributed to predisposing causes, conditioning illness or poor prophylaxis. Group B had an 80% success rate but required more rigorous prophylaxis measures, actual polishing of appliances by the operator, and removal of bands every 6 months. In Group C, if the adhesives were made with fine particles, they offered less of a plaque trap. The author cautions against etching in patients with a predisposition to dental caries. The use of straight-wire procedures, with less loop formation, has reduced the enamel attacks and made prophylaxis easier. Gingival tissue is healthier. The key to minimal decalcification and caries during orthodontic treatment is rigorous prophylaxis. It cannot be stressed too much to the patient. T. M. Graber
Measurement of the Ability to Control Muscles Forces in Man
Jaw
G. R. Lewis and R. Yemm J. Dent.
Res. 62:82/-824,
1983
With great interest in both functional and parafunctional activity of the jaw muscles, many experiments have been performed on their control mechanisms. Most of this information has been obtained to determine the neural pathway, but not the actual role of these mechanisms. The present experiments were designed to investigate the ability of jaw-closing muscles to exert controlled forces. It was also the objective to develop a testing method that could be used to examine those factors which might have an effect on these control mechanisms. Five adult male subjects. ranging in age from 25 to 41 years, were asked to track a moving waveform on an oscilloscope screen with the output of a stiff-beamed force transducer placed between the upper and lower premolar teeth on the right side of the mouth. The difference between the target signal and the force transducer output was obtained by means of a difference amplifier, so that a negative output was registered if the subject did not clench hard enough and a positive output was obtained if he clenched too hard. This error signal was recorded on a second oscilloscope not being followed by the experimental subjects. It was found that a period of learning was needed. About half of the 30-minute experimental time was needed to learn to attain the required objectives. Once learned, the technique appeared reliable. The responses were similar qualitatively, regardless of the force range demanded. Quantitatively, however, the greater the force demanded, the greater the error. The authors suggest, as a result of their pilot study, that the most useful parameter for comparison of different subjects may be the average error occurring at low force levels, since this minimizes the effect of uncontrollable variables. such as muscle fatigue and bulk. T. M. Graber
The Function of the Inferior Lateral Pterygoid Muscle
Head of the
W. W. Wood, K. Takada, and A. G. Hannamz J. Dent.
Res. 62:691,
1983
There has been a great deal of interest recently in the lateral pterygoid muscle and its possible role in TMJ disturbances. Much of the literature is on the su-
tivity. A total of 100 taps in each direction resulted in 88 SPs and 53 jaw jerks downward, and 61 SPs and 34 jaw jerks backward. The upward taps elicited ‘75 SPs and 38 jaw jerks. Not only the duration of the silent period but all reflex responses were remarkably inconsistent , despite standardized and controlled conditions. It is concluded that the duration of the SP is not a feasible diagnostic criterion for temporomandibular joint dysfunction. T. M. Graber
Alterations Orthodontic
produced in Dental Enamel by Appliances
C. Klein de Tolcachir C. J. Dent.
Res.
93:5/4,
1983
The objectives of this study were to assessthe relative effect of different orthodontic appliances on the enamel surface of teeth involved in orthodontic therapy. Conclusions are based on a previous report given in Lyon, France, covering a 20-year period, plus the author’s own 12-year didactic and clinical experience. Patients from the University clinic were divided into three groups according to the type of orthodontic appliances being used. Group A was treated with removable appliances; Group B consisted of patients with conventional orthodontic multibanded appliances cemented to the teeth; Group C was made up of patients with brackets bonded directly to the teeth. Assessments were made before, during, and after orthodontic treatment. Plaque and attacks on the enamel surfaces can be prevented by proper oral hygiene. In Group A, good results were achieved in 90% of the cases, although caries continued to occur. This was attributed to predisposing causes, conditioning illness or poor prophylaxis. Group B had an 80% success rate but required more rigorous prophylaxis measures, actual polishing of appliances by the operator, and removal of bands every 6 months. In Group C, if the adhesives were made with fine particles, they offered less of a plaque trap. The author cautions against etching in patients with a predisposition to dental caries. The use of straight-wire procedures, with less loop formation, has reduced the enamel attacks and made prophylaxis easier. Gingival tissue is healthier. The key to minimal decalcification and caries during orthodontic treatment is rigorous prophylaxis. It cannot be stressed too much to the patient. T. M. Graber
Measurement of the Ability to Control Muscles Forces in Man
Jaw
G. R. Lewis and R. Yemm J. Dent.
Res. 62:82/-824,
1983
With great interest in both functional and parafunctional activity of the jaw muscles, many experiments have been performed on their control mechanisms. Most of this information has been obtained to determine the neural pathway, but not the actual role of these mechanisms. The present experiments were designed to investigate the ability of jaw-closing muscles to exert controlled forces. It was also the objective to develop a testing method that could be used to examine those factors which might have an effect on these control mechanisms. Five adult male subjects. ranging in age from 25 to 41 years, were asked to track a moving waveform on an oscilloscope screen with the output of a stiff-beamed force transducer placed between the upper and lower premolar teeth on the right side of the mouth. The difference between the target signal and the force transducer output was obtained by means of a difference amplifier, so that a negative output was registered if the subject did not clench hard enough and a positive output was obtained if he clenched too hard. This error signal was recorded on a second oscilloscope not being followed by the experimental subjects. It was found that a period of learning was needed. About half of the 30-minute experimental time was needed to learn to attain the required objectives. Once learned, the technique appeared reliable. The responses were similar qualitatively, regardless of the force range demanded. Quantitatively, however, the greater the force demanded, the greater the error. The authors suggest, as a result of their pilot study, that the most useful parameter for comparison of different subjects may be the average error occurring at low force levels, since this minimizes the effect of uncontrollable variables. such as muscle fatigue and bulk. T. M. Graber
The Function of the Inferior Lateral Pterygoid Muscle
Head of the
W. W. Wood, K. Takada, and A. G. Hannamz J. Dent.
Res. 62:691,
1983
There has been a great deal of interest recently in the lateral pterygoid muscle and its possible role in TMJ disturbances. Much of the literature is on the su-